../deps/icu-small/source/common/ucnvmbcs.cpp

Bug Summary

File:	out/../deps/icu-small/source/common/ucnvmbcs.cpp
Warning:	line 1135, column 24 The left operand of '<=' is a garbage value
Annotated Source Code

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1// © 2016 and later: Unicode, Inc. and others.
2// License & terms of use: http://www.unicode.org/copyright.html
3/*
4******************************************************************************
5*
6*   Copyright (C) 2000-2016, International Business Machines
7*   Corporation and others.  All Rights Reserved.
8*
9******************************************************************************
10*   file name:  ucnvmbcs.cpp
11*   encoding:   UTF-8
12*   tab size:   8 (not used)
13*   indentation:4
14*
15*   created on: 2000jul03
16*   created by: Markus W. Scherer
17*
18*   The current code in this file replaces the previous implementation
19*   of conversion code from multi-byte codepages to Unicode and back.
20*   This implementation supports the following:
21*   - legacy variable-length codepages with up to 4 bytes per character
22*   - all Unicode code points (up to 0x10ffff)
23*   - efficient distinction of unassigned vs. illegal byte sequences
24*   - it is possible in fromUnicode() to directly deal with simple
25*     stateful encodings (used for EBCDIC_STATEFUL)
26*   - it is possible to convert Unicode code points
27*     to a single zero byte (but not as a fallback except for SBCS)
28*
29*   Remaining limitations in fromUnicode:
30*   - byte sequences must not have leading zero bytes
31*   - except for SBCS codepages: no fallback mapping from Unicode to a zero byte
32*   - limitation to up to 4 bytes per character
33*
34*   ICU 2.8 (late 2003) adds a secondary data structure which lifts some of these
35*   limitations and adds m:n character mappings and other features.
36*   See ucnv_ext.h for details.
37*
38*   Change history: 
39*
40*    5/6/2001       Ram       Moved  MBCS_SINGLE_RESULT_FROM_U,MBCS_STAGE_2_FROM_U,
41*                             MBCS_VALUE_2_FROM_STAGE_2, MBCS_VALUE_4_FROM_STAGE_2
42*                             macros to ucnvmbcs.h file
43*/

45#include "unicode/utypes.h"

47#if !UCONFIG_NO_CONVERSION0 && !UCONFIG_NO_LEGACY_CONVERSION0

49#include "unicode/ucnv.h"
50#include "unicode/ucnv_cb.h"
51#include "unicode/udata.h"
52#include "unicode/uset.h"
53#include "unicode/utf8.h"
54#include "unicode/utf16.h"
55#include "ucnv_bld.h"
56#include "ucnvmbcs.h"
57#include "ucnv_ext.h"
58#include "ucnv_cnv.h"
59#include "cmemory.h"
60#include "cstring.h"
61#include "umutex.h"
62#include "ustr_imp.h"

64/* control optimizations according to the platform */
65#define MBCS_UNROLL_SINGLE_TO_BMP1 1
66#define MBCS_UNROLL_SINGLE_FROM_BMP0 0

68/*
* _MBCSHeader versions 5.3 & 4.3
* (Note that the _MBCSHeader version is in addition to the converter formatVersion.)
*
* This version is optional. Version 5 is used for incompatible data format changes.
* makeconv will continue to generate version 4 files if possible.
*
* Changes from version 4:
*
* The main difference is an additional _MBCSHeader field with
* - the length (number of uint32_t) of the _MBCSHeader
* - flags for further incompatible data format changes
* - flags for further, backward compatible data format changes
*
* The MBCS_OPT_FROM_U flag indicates that most of the fromUnicode data is omitted from
* the file and needs to be reconstituted at load time.
* This requires a utf8Friendly format with an additional mbcsIndex table for fast
* (and UTF-8-friendly) fromUnicode conversion for Unicode code points up to maxFastUChar.
* (For details about these structures see below, and see ucnvmbcs.h.)
*
*   utf8Friendly also implies that the fromUnicode mappings are stored in ascending order
*   of the Unicode code points. (This requires that the .ucm file has the |0 etc.
*   precision markers for all mappings.)
*
*   All fallbacks have been moved to the extension table, leaving only roundtrips in the
*   omitted data that can be reconstituted from the toUnicode data.
*
*   Of the stage 2 table, the part corresponding to maxFastUChar and below is omitted.
*   With only roundtrip mappings in the base fromUnicode data, this part is fully
*   redundant with the mbcsIndex and will be reconstituted from that (also using the
*   stage 1 table which contains the information about how stage 2 was compacted).
*
*   The rest of the stage 2 table, the part for code points above maxFastUChar,
*   is stored in the file and will be appended to the reconstituted part.
*
*   The entire fromUBytes array is omitted from the file and will be reconstitued.
*   This is done by enumerating all toUnicode roundtrip mappings, performing
*   each mapping (using the stage 1 and reconstituted stage 2 tables) and
*   writing instead of reading the byte values.
*
* _MBCSHeader version 4.3
*
* Change from version 4.2:
* - Optional utf8Friendly data structures, with 64-entry stage 3 block
*   allocation for parts of the BMP, and an additional mbcsIndex in non-SBCS
*   files which can be used instead of stages 1 & 2.
*   Faster lookups for roundtrips from most commonly used characters,
*   and lookups from UTF-8 byte sequences with a natural bit distribution.
*   See ucnvmbcs.h for more details.
*
* Change from version 4.1:
* - Added an optional extension table structure at the end of the .cnv file.
*   It is present if the upper bits of the header flags field contains a non-zero
*   byte offset to it.
*   Files that contain only a conversion table and no base table
*   use the special outputType MBCS_OUTPUT_EXT_ONLY.
*   These contain the base table name between the MBCS header and the extension
*   data.
*
* Change from version 4.0:
* - Replace header.reserved with header.fromUBytesLength so that all
*   fields in the data have length.
*
* Changes from version 3 (for performance improvements):
* - new bit distribution for state table entries
* - reordered action codes
* - new data structure for single-byte fromUnicode
*   + stage 2 only contains indexes
*   + stage 3 stores 16 bits per character with classification bits 15..8
* - no multiplier for stage 1 entries
* - stage 2 for non-single-byte codepages contains the index and the flags in
*   one 32-bit value
* - 2-byte and 4-byte fromUnicode results are stored directly as 16/32-bit integers
*
* For more details about old versions of the MBCS data structure, see
* the corresponding versions of this file.
*
* Converting stateless codepage data ---------------------------------------***
* (or codepage data with simple states) to Unicode.
*
* Data structure and algorithm for converting from complex legacy codepages
* to Unicode. (Designed before 2000-may-22.)
*
* The basic idea is that the structure of legacy codepages can be described
* with state tables.
* When reading a byte stream, each input byte causes a state transition.
* Some transitions result in the output of a code point, some result in
* "unassigned" or "illegal" output.
* This is used here for character conversion.
*
* The data structure begins with a state table consisting of a row
* per state, with 256 entries (columns) per row for each possible input
* byte value.
* Each entry is 32 bits wide, with two formats distinguished by
* the sign bit (bit 31):
*
* One format for transitional entries (bit 31 not set) for non-final bytes, and
* one format for final entries (bit 31 set).
* Both formats contain the number of the next state in the same bit
* positions.
* State 0 is the initial state.
*
* Most of the time, the offset values of subsequent states are added
* up to a scalar value. This value will eventually be the index of
* the Unicode code point in a table that follows the state table.
* The effect is that the code points for final state table rows
* are contiguous. The code points of final state rows follow each other
* in the order of the references to those final states by previous
* states, etc.
*
* For some terminal states, the offset is itself the output Unicode
* code point (16 bits for a BMP code point or 20 bits for a supplementary
* code point (stored as code point minus 0x10000 so that 20 bits are enough).
* For others, the code point in the Unicode table is stored with either
* one or two code units: one for BMP code points, two for a pair of
* surrogates.
* All code points for a final state entry take up the same number of code
* units, regardless of whether they all actually _use_ the same number
* of code units. This is necessary for simple array access.
*
* An additional feature comes in with what in ICU is called "fallback"
* mappings:
*
* In addition to round-trippable, precise, 1:1 mappings, there are often
* mappings defined between similar, though not the same, characters.
* Typically, such mappings occur only in fromUnicode mapping tables because
* Unicode has a superset repertoire of most other codepages. However, it
* is possible to provide such mappings in the toUnicode tables, too.
* In this case, the fallback mappings are partly integrated into the
* general state tables because the structure of the encoding includes their
* byte sequences.
* For final entries in an initial state, fallback mappings are stored in
* the entry itself like with roundtrip mappings.
* For other final entries, they are stored in the code units table if
* the entry is for a pair of code units.
* For single-unit results in the code units table, there is no space to
* alternatively hold a fallback mapping; in this case, the code unit
* is stored as U+fffe (unassigned), and the fallback mapping needs to
* be looked up by the scalar offset value in a separate table.
*
* "Unassigned" state entries really mean "structurally unassigned",
* i.e., such a byte sequence will never have a mapping result.
*
* The interpretation of the bits in each entry is as follows:
*
* Bit 31 not set, not a terminal entry ("transitional"):
* 30..24 next state
* 23..0  offset delta, to be added up
*
* Bit 31 set, terminal ("final") entry:
* 30..24 next state (regardless of action code)
* 23..20 action code:
*        action codes 0 and 1 result in precise-mapping Unicode code points
*        0  valid byte sequence
*           19..16 not used, 0
*           15..0  16-bit Unicode BMP code point
*                  never U+fffe or U+ffff
*        1  valid byte sequence
*           19..0  20-bit Unicode supplementary code point
*                  never U+fffe or U+ffff
*
*        action codes 2 and 3 result in fallback (unidirectional-mapping) Unicode code points
*        2  valid byte sequence (fallback)
*           19..16 not used, 0
*           15..0  16-bit Unicode BMP code point as fallback result
*        3  valid byte sequence (fallback)
*           19..0  20-bit Unicode supplementary code point as fallback result
*
*        action codes 4 and 5 may result in roundtrip/fallback/unassigned/illegal results
*        depending on the code units they result in
*        4  valid byte sequence
*           19..9  not used, 0
*            8..0  final offset delta
*                  pointing to one 16-bit code unit which may be
*                  fffe  unassigned -- look for a fallback for this offset
*                  ffff  illegal
*        5  valid byte sequence
*           19..9  not used, 0
*            8..0  final offset delta
*                  pointing to two 16-bit code units
*                  (typically UTF-16 surrogates)
*                  the result depends on the first code unit as follows:
*                  0000..d7ff  roundtrip BMP code point (1st alone)
*                  d800..dbff  roundtrip surrogate pair (1st, 2nd)
*                  dc00..dfff  fallback surrogate pair (1st-400, 2nd)
*                  e000        roundtrip BMP code point (2nd alone)
*                  e001        fallback BMP code point (2nd alone)
*                  fffe        unassigned
*                  ffff        illegal
*           (the final offset deltas are at most 255 * 2,
*            times 2 because of storing code unit pairs)
*
*        6  unassigned byte sequence
*           19..16 not used, 0
*           15..0  16-bit Unicode BMP code point U+fffe (new with version 2)
*                  this does not contain a final offset delta because the main
*                  purpose of this action code is to save scalar offset values;
*                  therefore, fallback values cannot be assigned to byte
*                  sequences that result in this action code
*        7  illegal byte sequence
*           19..16 not used, 0
*           15..0  16-bit Unicode BMP code point U+ffff (new with version 2)
*        8  state change only
*           19..0  not used, 0
*           useful for state changes in simple stateful encodings,
*           at Shift-In/Shift-Out codes
*
*
*        9..15 reserved for future use
*           current implementations will only perform a state change
*           and ignore bits 19..0
*
* An encoding with contiguous ranges of unassigned byte sequences, like
* Shift-JIS and especially EUC-TW, can be stored efficiently by having
* at least two states for the trail bytes:
* One trail byte state that results in code points, and one that only
* has "unassigned" and "illegal" terminal states.
*
* Note: partly by accident, this data structure supports simple stateful
* encodings without any additional logic.
* Currently, only simple Shift-In/Shift-Out schemes are handled with
* appropriate state tables (especially EBCDIC_STATEFUL!).
*
* MBCS version 2 added:
* unassigned and illegal action codes have U+fffe and U+ffff
* instead of unused bits; this is useful for _MBCS_SINGLE_SIMPLE_GET_NEXT_BMP()
*
* Converting from Unicode to codepage bytes --------------------------------***
*
* The conversion data structure for fromUnicode is designed for the known
* structure of Unicode. It maps from 21-bit code points (0..0x10ffff) to
* a sequence of 1..4 bytes, in addition to a flag that indicates if there is
* a roundtrip mapping.
*
* The lookup is done with a 3-stage trie, using 11/6/4 bits for stage 1/2/3
* like in the character properties table.
* The beginning of the trie is at offsetFromUTable, the beginning of stage 3
* with the resulting bytes is at offsetFromUBytes.
*
* Beginning with version 4, single-byte codepages have a significantly different
* trie compared to other codepages.
* In all cases, the entry in stage 1 is directly the index of the block of
* 64 entries in stage 2.
*
* Single-byte lookup:
*
* Stage 2 only contains 16-bit indexes directly to the 16-blocks in stage 3.
* Stage 3 contains one 16-bit word per result:
* Bits 15..8 indicate the kind of result:
*    f  roundtrip result
*    c  fallback result from private-use code point
*    8  fallback result from other code points
*    0  unassigned
* Bits 7..0 contain the codepage byte. A zero byte is always possible.
*
* In version 4.3, the runtime code can build an sbcsIndex for a utf8Friendly
* file. For 2-byte UTF-8 byte sequences and some 3-byte sequences the lookup
* becomes a 2-stage (single-index) trie lookup with 6 bits for stage 3.
* ASCII code points can be looked up with a linear array access into stage 3.
* See maxFastUChar and other details in ucnvmbcs.h.
*
* Multi-byte lookup:
*
* Stage 2 contains a 32-bit word for each 16-block in stage 3:
* Bits 31..16 contain flags for which stage 3 entries contain roundtrip results
*             test: MBCS_FROM_U_IS_ROUNDTRIP(stage2Entry, c)
*             If this test is false, then a non-zero result will be interpreted as
*             a fallback mapping.
* Bits 15..0  contain the index to stage 3, which must be multiplied by 16*(bytes per char)
*
* Stage 3 contains 2, 3, or 4 bytes per result.
* 2 or 4 bytes are stored as uint16_t/uint32_t in platform endianness,
* while 3 bytes are stored as bytes in big-endian order.
* Leading zero bytes are ignored, and the number of bytes is counted.
* A zero byte mapping result is possible as a roundtrip result.
* For some output types, the actual result is processed from this;
* see ucnv_MBCSFromUnicodeWithOffsets().
*
* Note that stage 1 always contains 0x440=1088 entries (0x440==0x110000>>10),
* or (version 3 and up) for BMP-only codepages, it contains 64 entries.
*
* In version 4.3, a utf8Friendly file contains an mbcsIndex table.
* For 2-byte UTF-8 byte sequences and most 3-byte sequences the lookup
* becomes a 2-stage (single-index) trie lookup with 6 bits for stage 3.
* ASCII code points can be looked up with a linear array access into stage 3.
* See maxFastUChar, mbcsIndex and other details in ucnvmbcs.h.
*
* In version 3, stage 2 blocks may overlap by multiples of the multiplier
* for compaction.
* In version 4, stage 2 blocks (and for single-byte codepages, stage 3 blocks)
* may overlap by any number of entries.
*
* MBCS version 2 added:
* the converter checks for known output types, which allows
* adding new ones without crashing an unaware converter
*/

365/**
* Callback from ucnv_MBCSEnumToUnicode(), takes 32 mappings from
* consecutive sequences of bytes, starting from the one encoded in value,
* to Unicode code points. (Multiple mappings to reduce per-function call overhead.)
* Does not currently support m:n mappings or reverse fallbacks.
* This function will not be called for sequences of bytes with leading zeros.
*
* @param context an opaque pointer, as passed into ucnv_MBCSEnumToUnicode()
* @param value contains 1..4 bytes of the first byte sequence, right-aligned
* @param codePoints resulting Unicode code points, or negative if a byte sequence does
*        not map to anything
* @return TRUE to continue enumeration, FALSE to stop
*/
378typedef UBool U_CALLCONV
379UConverterEnumToUCallback(const void *context, uint32_t value, UChar32 codePoints[32]);

381static void U_CALLCONV
382ucnv_MBCSLoad(UConverterSharedData *sharedData,
        UConverterLoadArgs *pArgs,
        const uint8_t *raw,
        UErrorCode *pErrorCode);

387static void U_CALLCONV
388ucnv_MBCSUnload(UConverterSharedData *sharedData);

390static void U_CALLCONV
391ucnv_MBCSOpen(UConverter *cnv,
            UConverterLoadArgs *pArgs,
            UErrorCode *pErrorCode);

395static UChar32 U_CALLCONV
396ucnv_MBCSGetNextUChar(UConverterToUnicodeArgs *pArgs,
                UErrorCode *pErrorCode);

399static void U_CALLCONV
400ucnv_MBCSGetStarters(const UConverter* cnv,
               UBool starters[256],
               UErrorCode *pErrorCode);

404U_CDECL_BEGINextern "C" {
405static const char* U_CALLCONV
406ucnv_MBCSGetName(const UConverter *cnv);
407U_CDECL_END}

409static void U_CALLCONV
410ucnv_MBCSWriteSub(UConverterFromUnicodeArgs *pArgs,
            int32_t offsetIndex,
            UErrorCode *pErrorCode);

414static UChar32 U_CALLCONV
415ucnv_MBCSGetNextUChar(UConverterToUnicodeArgs *pArgs,
                UErrorCode *pErrorCode);

418static void U_CALLCONV
419ucnv_SBCSFromUTF8(UConverterFromUnicodeArgs *pFromUArgs,
                UConverterToUnicodeArgs *pToUArgs,
                UErrorCode *pErrorCode);

423static void U_CALLCONV
424ucnv_MBCSGetUnicodeSet(const UConverter *cnv,
                 const USetAdder *sa,
                 UConverterUnicodeSet which,
                 UErrorCode *pErrorCode);

429static void U_CALLCONV
430ucnv_DBCSFromUTF8(UConverterFromUnicodeArgs *pFromUArgs,
                UConverterToUnicodeArgs *pToUArgs,
                UErrorCode *pErrorCode);

434static const UConverterImpl _SBCSUTF8Impl={
  UCNV_MBCS,

  ucnv_MBCSLoad,
  ucnv_MBCSUnload,

  ucnv_MBCSOpen,
  NULL__null,
  NULL__null,

  ucnv_MBCSToUnicodeWithOffsetsucnv_MBCSToUnicodeWithOffsets_71,
  ucnv_MBCSToUnicodeWithOffsetsucnv_MBCSToUnicodeWithOffsets_71,
  ucnv_MBCSFromUnicodeWithOffsetsucnv_MBCSFromUnicodeWithOffsets_71,
  ucnv_MBCSFromUnicodeWithOffsetsucnv_MBCSFromUnicodeWithOffsets_71,
  ucnv_MBCSGetNextUChar,

  ucnv_MBCSGetStarters,
  ucnv_MBCSGetName,
  ucnv_MBCSWriteSub,
  NULL__null,
  ucnv_MBCSGetUnicodeSet,

  NULL__null,
  ucnv_SBCSFromUTF8
458};

460static const UConverterImpl _DBCSUTF8Impl={
  UCNV_MBCS,

  ucnv_MBCSLoad,
  ucnv_MBCSUnload,

  ucnv_MBCSOpen,
  NULL__null,
  NULL__null,

  ucnv_MBCSToUnicodeWithOffsetsucnv_MBCSToUnicodeWithOffsets_71,
  ucnv_MBCSToUnicodeWithOffsetsucnv_MBCSToUnicodeWithOffsets_71,
  ucnv_MBCSFromUnicodeWithOffsetsucnv_MBCSFromUnicodeWithOffsets_71,
  ucnv_MBCSFromUnicodeWithOffsetsucnv_MBCSFromUnicodeWithOffsets_71,
  ucnv_MBCSGetNextUChar,

  ucnv_MBCSGetStarters,
  ucnv_MBCSGetName,
  ucnv_MBCSWriteSub,
  NULL__null,
  ucnv_MBCSGetUnicodeSet,

  NULL__null,
  ucnv_DBCSFromUTF8
484};

486static const UConverterImpl _MBCSImpl={
  UCNV_MBCS,

  ucnv_MBCSLoad,
  ucnv_MBCSUnload,

  ucnv_MBCSOpen,
  NULL__null,
  NULL__null,

  ucnv_MBCSToUnicodeWithOffsetsucnv_MBCSToUnicodeWithOffsets_71,
  ucnv_MBCSToUnicodeWithOffsetsucnv_MBCSToUnicodeWithOffsets_71,
  ucnv_MBCSFromUnicodeWithOffsetsucnv_MBCSFromUnicodeWithOffsets_71,
  ucnv_MBCSFromUnicodeWithOffsetsucnv_MBCSFromUnicodeWithOffsets_71,
  ucnv_MBCSGetNextUChar,

  ucnv_MBCSGetStarters,
  ucnv_MBCSGetName,
  ucnv_MBCSWriteSub,
  NULL__null,
  ucnv_MBCSGetUnicodeSet,
  NULL__null,
  NULL__null
509};

511/* Static data is in tools/makeconv/ucnvstat.c for data-based
* converters. Be sure to update it as well.
*/

515const UConverterSharedData _MBCSData_MBCSData_71={
  sizeof(UConverterSharedData), 1,
  NULL__null, NULL__null, FALSE0, TRUE1, &_MBCSImpl,
  0, UCNV_MBCS_TABLE_INITIALIZER{ 0, 0, 0, 0, __null, __null, __null, __null, __null, __null,
 { 0 }, __null, __null, 0, 0, 0, false, 0, 0, __null, __null,
 __null, __null }
519};


522/* GB 18030 data ------------------------------------------------------------ */

524/* helper macros for linear values for GB 18030 four-byte sequences */
525#define LINEAR_18030(a, b, c, d)((((a)*10+(b))*126L+(c))*10L+(d)) ((((a)*10+(b))*126L+(c))*10L+(d))

527#define LINEAR_18030_BASE((((0x81)*10+(0x30))*126L+(0x81))*10L+(0x30)) LINEAR_18030(0x81, 0x30, 0x81, 0x30)((((0x81)*10+(0x30))*126L+(0x81))*10L+(0x30))

529#define LINEAR(x)((((x>>24)*10+((x>>16)&0xff))*126L+((x>>
8)&0xff))*10L+(x&0xff)) LINEAR_18030(x>>24, (x>>16)&0xff, (x>>8)&0xff, x&0xff)((((x>>24)*10+((x>>16)&0xff))*126L+((x>>
8)&0xff))*10L+(x&0xff))

531/*
* Some ranges of GB 18030 where both the Unicode code points and the
* GB four-byte sequences are contiguous and are handled algorithmically by
* the special callback functions below.
* The values are start & end of Unicode & GB codes.
*
* Note that single surrogates are not mapped by GB 18030
* as of the re-released mapping tables from 2000-nov-30.
*/
540static const uint32_t
541gb18030Ranges[14][4]={
  {0x10000, 0x10FFFF, LINEAR(0x90308130)((((0x90308130>>24)*10+((0x90308130>>16)&0xff
))*126L+((0x90308130>>8)&0xff))*10L+(0x90308130&
0xff)), LINEAR(0xE3329A35)((((0xE3329A35>>24)*10+((0xE3329A35>>16)&0xff
))*126L+((0xE3329A35>>8)&0xff))*10L+(0xE3329A35&
0xff))},
  {0x9FA6, 0xD7FF, LINEAR(0x82358F33)((((0x82358F33>>24)*10+((0x82358F33>>16)&0xff
))*126L+((0x82358F33>>8)&0xff))*10L+(0x82358F33&
0xff)), LINEAR(0x8336C738)((((0x8336C738>>24)*10+((0x8336C738>>16)&0xff
))*126L+((0x8336C738>>8)&0xff))*10L+(0x8336C738&
0xff))},
  {0x0452, 0x1E3E, LINEAR(0x8130D330)((((0x8130D330>>24)*10+((0x8130D330>>16)&0xff
))*126L+((0x8130D330>>8)&0xff))*10L+(0x8130D330&
0xff)), LINEAR(0x8135F436)((((0x8135F436>>24)*10+((0x8135F436>>16)&0xff
))*126L+((0x8135F436>>8)&0xff))*10L+(0x8135F436&
0xff))},
  {0x1E40, 0x200F, LINEAR(0x8135F438)((((0x8135F438>>24)*10+((0x8135F438>>16)&0xff
))*126L+((0x8135F438>>8)&0xff))*10L+(0x8135F438&
0xff)), LINEAR(0x8136A531)((((0x8136A531>>24)*10+((0x8136A531>>16)&0xff
))*126L+((0x8136A531>>8)&0xff))*10L+(0x8136A531&
0xff))},
  {0xE865, 0xF92B, LINEAR(0x8336D030)((((0x8336D030>>24)*10+((0x8336D030>>16)&0xff
))*126L+((0x8336D030>>8)&0xff))*10L+(0x8336D030&
0xff)), LINEAR(0x84308534)((((0x84308534>>24)*10+((0x84308534>>16)&0xff
))*126L+((0x84308534>>8)&0xff))*10L+(0x84308534&
0xff))},
  {0x2643, 0x2E80, LINEAR(0x8137A839)((((0x8137A839>>24)*10+((0x8137A839>>16)&0xff
))*126L+((0x8137A839>>8)&0xff))*10L+(0x8137A839&
0xff)), LINEAR(0x8138FD38)((((0x8138FD38>>24)*10+((0x8138FD38>>16)&0xff
))*126L+((0x8138FD38>>8)&0xff))*10L+(0x8138FD38&
0xff))},
  {0xFA2A, 0xFE2F, LINEAR(0x84309C38)((((0x84309C38>>24)*10+((0x84309C38>>16)&0xff
))*126L+((0x84309C38>>8)&0xff))*10L+(0x84309C38&
0xff)), LINEAR(0x84318537)((((0x84318537>>24)*10+((0x84318537>>16)&0xff
))*126L+((0x84318537>>8)&0xff))*10L+(0x84318537&
0xff))},
  {0x3CE1, 0x4055, LINEAR(0x8231D438)((((0x8231D438>>24)*10+((0x8231D438>>16)&0xff
))*126L+((0x8231D438>>8)&0xff))*10L+(0x8231D438&
0xff)), LINEAR(0x8232AF32)((((0x8232AF32>>24)*10+((0x8232AF32>>16)&0xff
))*126L+((0x8232AF32>>8)&0xff))*10L+(0x8232AF32&
0xff))},
  {0x361B, 0x3917, LINEAR(0x8230A633)((((0x8230A633>>24)*10+((0x8230A633>>16)&0xff
))*126L+((0x8230A633>>8)&0xff))*10L+(0x8230A633&
0xff)), LINEAR(0x8230F237)((((0x8230F237>>24)*10+((0x8230F237>>16)&0xff
))*126L+((0x8230F237>>8)&0xff))*10L+(0x8230F237&
0xff))},
  {0x49B8, 0x4C76, LINEAR(0x8234A131)((((0x8234A131>>24)*10+((0x8234A131>>16)&0xff
))*126L+((0x8234A131>>8)&0xff))*10L+(0x8234A131&
0xff)), LINEAR(0x8234E733)((((0x8234E733>>24)*10+((0x8234E733>>16)&0xff
))*126L+((0x8234E733>>8)&0xff))*10L+(0x8234E733&
0xff))},
  {0x4160, 0x4336, LINEAR(0x8232C937)((((0x8232C937>>24)*10+((0x8232C937>>16)&0xff
))*126L+((0x8232C937>>8)&0xff))*10L+(0x8232C937&
0xff)), LINEAR(0x8232F837)((((0x8232F837>>24)*10+((0x8232F837>>16)&0xff
))*126L+((0x8232F837>>8)&0xff))*10L+(0x8232F837&
0xff))},
  {0x478E, 0x4946, LINEAR(0x8233E838)((((0x8233E838>>24)*10+((0x8233E838>>16)&0xff
))*126L+((0x8233E838>>8)&0xff))*10L+(0x8233E838&
0xff)), LINEAR(0x82349638)((((0x82349638>>24)*10+((0x82349638>>16)&0xff
))*126L+((0x82349638>>8)&0xff))*10L+(0x82349638&
0xff))},
  {0x44D7, 0x464B, LINEAR(0x8233A339)((((0x8233A339>>24)*10+((0x8233A339>>16)&0xff
))*126L+((0x8233A339>>8)&0xff))*10L+(0x8233A339&
0xff)), LINEAR(0x8233C931)((((0x8233C931>>24)*10+((0x8233C931>>16)&0xff
))*126L+((0x8233C931>>8)&0xff))*10L+(0x8233C931&
0xff))},
  {0xFFE6, 0xFFFF, LINEAR(0x8431A234)((((0x8431A234>>24)*10+((0x8431A234>>16)&0xff
))*126L+((0x8431A234>>8)&0xff))*10L+(0x8431A234&
0xff)), LINEAR(0x8431A439)((((0x8431A439>>24)*10+((0x8431A439>>16)&0xff
))*126L+((0x8431A439>>8)&0xff))*10L+(0x8431A439&
0xff))}
556};

558/* bit flag for UConverter.options indicating GB 18030 special handling */
559#define _MBCS_OPTION_GB180300x8000 0x8000

561/* bit flag for UConverter.options indicating KEIS,JEF,JIF special handling */
562#define _MBCS_OPTION_KEIS0x01000 0x01000
563#define _MBCS_OPTION_JEF0x02000  0x02000
564#define _MBCS_OPTION_JIPS0x04000 0x04000

566#define KEIS_SO_CHAR_10x0A 0x0A
567#define KEIS_SO_CHAR_20x42 0x42
568#define KEIS_SI_CHAR_10x0A 0x0A
569#define KEIS_SI_CHAR_20x41 0x41

571#define JEF_SO_CHAR0x28 0x28
572#define JEF_SI_CHAR0x29 0x29

574#define JIPS_SO_CHAR_10x1A 0x1A
575#define JIPS_SO_CHAR_20x70 0x70
576#define JIPS_SI_CHAR_10x1A 0x1A
577#define JIPS_SI_CHAR_20x71 0x71

579enum SISO_Option {
  SI,
  SO
582};
583typedef enum SISO_Option SISO_Option;

585static int32_t getSISOBytes(SISO_Option option, uint32_t cnvOption, uint8_t *value) {
  int32_t SISOLength = 0;

  switch (option) {
      case SI:
          if ((cnvOption&_MBCS_OPTION_KEIS0x01000)!=0) {
              value[0] = KEIS_SI_CHAR_10x0A;
              value[1] = KEIS_SI_CHAR_20x41;
              SISOLength = 2;
          } else if ((cnvOption&_MBCS_OPTION_JEF0x02000)!=0) {
              value[0] = JEF_SI_CHAR0x29;
              SISOLength = 1;
          } else if ((cnvOption&_MBCS_OPTION_JIPS0x04000)!=0) {
              value[0] = JIPS_SI_CHAR_10x1A;
              value[1] = JIPS_SI_CHAR_20x71;
              SISOLength = 2;
          } else {
              value[0] = UCNV_SI0x0F;
              SISOLength = 1;
          }
          break;
      case SO:
          if ((cnvOption&_MBCS_OPTION_KEIS0x01000)!=0) {
              value[0] = KEIS_SO_CHAR_10x0A;
              value[1] = KEIS_SO_CHAR_20x42;
              SISOLength = 2;
          } else if ((cnvOption&_MBCS_OPTION_JEF0x02000)!=0) {
              value[0] = JEF_SO_CHAR0x28;
              SISOLength = 1;
          } else if ((cnvOption&_MBCS_OPTION_JIPS0x04000)!=0) {
              value[0] = JIPS_SO_CHAR_10x1A;
              value[1] = JIPS_SO_CHAR_20x70;
              SISOLength = 2;
          } else {
              value[0] = UCNV_SO0x0E;
              SISOLength = 1;
          }
          break;
      default:
          /* Should never happen. */
          break;
  }

  return SISOLength;
629}

631/* Miscellaneous ------------------------------------------------------------ */

633/* similar to ucnv_MBCSGetNextUChar() but recursive */
634static UBool
635enumToU(UConverterMBCSTable *mbcsTable, int8_t stateProps[],
      int32_t state, uint32_t offset,
      uint32_t value,
      UConverterEnumToUCallback *callback, const void *context,
      UErrorCode *pErrorCode) {
  UChar32 codePoints[32];
  const int32_t *row;
  const uint16_t *unicodeCodeUnits;
  UChar32 anyCodePoints;
  int32_t b, limit;

  row=mbcsTable->stateTable[state];
  unicodeCodeUnits=mbcsTable->unicodeCodeUnits;

  value<<=8;
  anyCodePoints=-1;  /* becomes non-negative if there is a mapping */

  b=(stateProps[state]&0x38)<<2;
  if(b==0 && stateProps[state]>=0x40) {
      /* skip byte sequences with leading zeros because they are not stored in the fromUnicode table */
      codePoints[0]=U_SENTINEL(-1);
      b=1;
  }
  limit=((stateProps[state]&7)+1)<<5;
  while(b<limit) {
      int32_t entry=row[b];
      if(MBCS_ENTRY_IS_TRANSITION(entry)((entry)>=0)) {
          int32_t nextState=MBCS_ENTRY_TRANSITION_STATE(entry)(((uint32_t)entry)>>24);
          if(stateProps[nextState]>=0) {
              /* recurse to a state with non-ignorable actions */
              if(!enumToU(
                      mbcsTable, stateProps, nextState,
                      offset+MBCS_ENTRY_TRANSITION_OFFSET(entry)((entry)&0xffffff),
                      value|(uint32_t)b,
                      callback, context,
                      pErrorCode)) {
                  return FALSE0;
              }
          }
          codePoints[b&0x1f]=U_SENTINEL(-1);
      } else {
          UChar32 c;
          int32_t action;

          /*
           * An if-else-if chain provides more reliable performance for
           * the most common cases compared to a switch.
           */
          action=MBCS_ENTRY_FINAL_ACTION(entry)((((uint32_t)entry)>>20)&0xf);
          if(action==MBCS_STATE_VALID_DIRECT_16) {
              /* output BMP code point */
              c=(UChar)MBCS_ENTRY_FINAL_VALUE_16(entry)(uint16_t)(entry);
          } else if(action==MBCS_STATE_VALID_16) {
              int32_t finalOffset=offset+MBCS_ENTRY_FINAL_VALUE_16(entry)(uint16_t)(entry);
              c=unicodeCodeUnits[finalOffset];
              if(c<0xfffe) {
                  /* output BMP code point */
              } else {
                  c=U_SENTINEL(-1);
              }
          } else if(action==MBCS_STATE_VALID_16_PAIR) {
              int32_t finalOffset=offset+MBCS_ENTRY_FINAL_VALUE_16(entry)(uint16_t)(entry);
              c=unicodeCodeUnits[finalOffset++];
              if(c<0xd800) {
                  /* output BMP code point below 0xd800 */
              } else if(c<=0xdbff) {
                  /* output roundtrip or fallback supplementary code point */
                  c=((c&0x3ff)<<10)+unicodeCodeUnits[finalOffset]+(0x10000-0xdc00);
              } else if(c==0xe000) {
                  /* output roundtrip BMP code point above 0xd800 or fallback BMP code point */
                  c=unicodeCodeUnits[finalOffset];
              } else {
                  c=U_SENTINEL(-1);
              }
          } else if(action==MBCS_STATE_VALID_DIRECT_20) {
              /* output supplementary code point */
              c=(UChar32)(MBCS_ENTRY_FINAL_VALUE(entry)((entry)&0xfffff)+0x10000);
          } else {
              c=U_SENTINEL(-1);
          }

          codePoints[b&0x1f]=c;
          anyCodePoints&=c;
      }
      if(((++b)&0x1f)==0) {
          if(anyCodePoints>=0) {
              if(!callback(context, value|(uint32_t)(b-0x20), codePoints)) {
                  return FALSE0;
              }
              anyCodePoints=-1;
          }
      }
  }
  return TRUE1;
729}

731/*
* Only called if stateProps[state]==-1.
* A recursive call may do stateProps[state]|=0x40 if this state is the target of an
* MBCS_STATE_CHANGE_ONLY.
*/
736static int8_t
737getStateProp(const int32_t (*stateTable)[256], int8_t stateProps[], int state) {
  const int32_t *row;
  int32_t min, max, entry, nextState;

  row=stateTable[state];
  stateProps[state]=0;

  /* find first non-ignorable state */
  for(min=0;; ++min) {
      entry=row[min];
      nextState=MBCS_ENTRY_STATE(entry)((((uint32_t)entry)>>24)&0x7f);
      if(stateProps[nextState]==-1) {
          getStateProp(stateTable, stateProps, nextState);
      }
      if(MBCS_ENTRY_IS_TRANSITION(entry)((entry)>=0)) {
          if(stateProps[nextState]>=0) {
              break;
          }
      } else if(MBCS_ENTRY_FINAL_ACTION(entry)((((uint32_t)entry)>>20)&0xf)<MBCS_STATE_UNASSIGNED) {
          break;
      }
      if(min==0xff) {
          stateProps[state]=-0x40;  /* (int8_t)0xc0 */
          return stateProps[state];
      }
  }
  stateProps[state]|=(int8_t)((min>>5)<<3);

  /* find last non-ignorable state */
  for(max=0xff; min<max; --max) {
      entry=row[max];
      nextState=MBCS_ENTRY_STATE(entry)((((uint32_t)entry)>>24)&0x7f);
      if(stateProps[nextState]==-1) {
          getStateProp(stateTable, stateProps, nextState);
      }
      if(MBCS_ENTRY_IS_TRANSITION(entry)((entry)>=0)) {
          if(stateProps[nextState]>=0) {
              break;
          }
      } else if(MBCS_ENTRY_FINAL_ACTION(entry)((((uint32_t)entry)>>20)&0xf)<MBCS_STATE_UNASSIGNED) {
          break;
      }
  }
  stateProps[state]|=(int8_t)(max>>5);

  /* recurse further and collect direct-state information */
  while(min<=max) {
      entry=row[min];
      nextState=MBCS_ENTRY_STATE(entry)((((uint32_t)entry)>>24)&0x7f);
      if(stateProps[nextState]==-1) {
          getStateProp(stateTable, stateProps, nextState);
      }
      if(MBCS_ENTRY_IS_FINAL(entry)((entry)<0)) {
          stateProps[nextState]|=0x40;
          if(MBCS_ENTRY_FINAL_ACTION(entry)((((uint32_t)entry)>>20)&0xf)<=MBCS_STATE_FALLBACK_DIRECT_20) {
              stateProps[state]|=0x40;
          }
      }
      ++min;
  }
  return stateProps[state];
798}

800/*
* Internal function enumerating the toUnicode data of an MBCS converter.
* Currently only used for reconstituting data for a MBCS_OPT_NO_FROM_U
* table, but could also be used for a future ucnv_getUnicodeSet() option
* that includes reverse fallbacks (after updating this function's implementation).
* Currently only handles roundtrip mappings.
* Does not currently handle extensions.
*/
808static void
809ucnv_MBCSEnumToUnicode(UConverterMBCSTable *mbcsTable,
                     UConverterEnumToUCallback *callback, const void *context,
                     UErrorCode *pErrorCode) {
  /*
   * Properties for each state, to speed up the enumeration.
   * Ignorable actions are unassigned/illegal/state-change-only:
   * They do not lead to mappings.
   *
   * Bits 7..6:
   * 1 direct/initial state (stateful converters have multiple)
   * 0 non-initial state with transitions or with non-ignorable result actions
   * -1 final state with only ignorable actions
   *
   * Bits 5..3:
   * The lowest byte value with non-ignorable actions is
   * value<<5 (rounded down).
   *
   * Bits 2..0:
   * The highest byte value with non-ignorable actions is
   * (value<<5)&0x1f (rounded up).
   */
  int8_t stateProps[MBCS_MAX_STATE_COUNT];
  int32_t state;

  uprv_memset(stateProps, -1, sizeof(stateProps)):: memset(stateProps, -1, sizeof(stateProps));

  /* recurse from state 0 and set all stateProps */
  getStateProp(mbcsTable->stateTable, stateProps, 0);

  for(state=0; state<mbcsTable->countStates; ++state) {
      /*if(stateProps[state]==-1) {
          printf("unused/unreachable <icu:state> %d\n", state);
      }*/
      if(stateProps[state]>=0x40) {
          /* start from each direct state */
          enumToU(
              mbcsTable, stateProps, state, 0, 0,
              callback, context,
              pErrorCode);
      }
  }
850}

852U_CFUNCextern "C" void 
853ucnv_MBCSGetFilteredUnicodeSetForUnicodeucnv_MBCSGetFilteredUnicodeSetForUnicode_71(const UConverterSharedData *sharedData,
                                       const USetAdder *sa,
                                       UConverterUnicodeSet which,
                                       UConverterSetFilter filter,
                                       UErrorCode *pErrorCode) {
  const UConverterMBCSTable *mbcsTable;
  const uint16_t *table;

  uint32_t st3;
  uint16_t st1, maxStage1, st2;

  UChar32 c;

  /* enumerate the from-Unicode trie table */
  mbcsTable=&sharedData->mbcs;
  table=mbcsTable->fromUnicodeTable;
  if(mbcsTable->unicodeMask&UCNV_HAS_SUPPLEMENTARY1) {
      maxStage1=0x440;
  } else {
      maxStage1=0x40;
  }

  c=0; /* keep track of the current code point while enumerating */

  if(mbcsTable->outputType==MBCS_OUTPUT_1) {
      const uint16_t *stage2, *stage3, *results;
      uint16_t minValue;

      results=(const uint16_t *)mbcsTable->fromUnicodeBytes;

      /*
       * Set a threshold variable for selecting which mappings to use.
       * See ucnv_MBCSSingleFromBMPWithOffsets() and
       * MBCS_SINGLE_RESULT_FROM_U() for details.
       */
      if(which==UCNV_ROUNDTRIP_SET) {
          /* use only roundtrips */
          minValue=0xf00;
      } else /* UCNV_ROUNDTRIP_AND_FALLBACK_SET */ {
          /* use all roundtrip and fallback results */
          minValue=0x800;
      }

      for(st1=0; st1<maxStage1; ++st1) {
          st2=table[st1];
          if(st2>maxStage1) {
              stage2=table+st2;
              for(st2=0; st2<64; ++st2) {
                  if((st3=stage2[st2])!=0) {
                      /* read the stage 3 block */
                      stage3=results+st3;

                      do {
                          if(*stage3++>=minValue) {
                              sa->add(sa->set, c);
                          }
                      } while((++c&0xf)!=0);
                  } else {
                      c+=16; /* empty stage 3 block */
                  }
              }
          } else {
              c+=1024; /* empty stage 2 block */
          }
      }
  } else {
      const uint32_t *stage2;
      const uint8_t *stage3, *bytes;
      uint32_t st3Multiplier;
      uint32_t value;
      UBool useFallback;

      bytes=mbcsTable->fromUnicodeBytes;

      useFallback=(UBool)(which==UCNV_ROUNDTRIP_AND_FALLBACK_SET);

      switch(mbcsTable->outputType) {
      case MBCS_OUTPUT_3:
      case MBCS_OUTPUT_4_EUC:
          st3Multiplier=3;
          break;
      case MBCS_OUTPUT_4:
          st3Multiplier=4;
          break;
      default:
          st3Multiplier=2;
          break;
      }

      for(st1=0; st1<maxStage1; ++st1) {
          st2=table[st1];
          if(st2>(maxStage1>>1)) {
              stage2=(const uint32_t *)table+st2;
              for(st2=0; st2<64; ++st2) {
                  if((st3=stage2[st2])!=0) {
                      /* read the stage 3 block */
                      stage3=bytes+st3Multiplier*16*(uint32_t)(uint16_t)st3;

                      /* get the roundtrip flags for the stage 3 block */
                      st3>>=16;

                      /*
                       * Add code points for which the roundtrip flag is set,
                       * or which map to non-zero bytes if we use fallbacks.
                       * See ucnv_MBCSFromUnicodeWithOffsets() for details.
                       */
                      switch(filter) {
                      case UCNV_SET_FILTER_NONE:
                          do {
                              if(st3&1) {
                                  sa->add(sa->set, c);
                                  stage3+=st3Multiplier;
                              } else if(useFallback) {
                                  uint8_t b=0;
                                  switch(st3Multiplier) {
                                  case 4:
                                      b|=*stage3++;
                                      U_FALLTHROUGH[[clang::fallthrough]];
                                  case 3:
                                      b|=*stage3++;
                                      U_FALLTHROUGH[[clang::fallthrough]];
                                  case 2:
                                      b|=stage3[0]|stage3[1];
                                      stage3+=2;
                                      U_FALLTHROUGH[[clang::fallthrough]];
                                  default:
                                      break;
                                  }
                                  if(b!=0) {
                                      sa->add(sa->set, c);
                                  }
                              }
                              st3>>=1;
                          } while((++c&0xf)!=0);
                          break;
                      case UCNV_SET_FILTER_DBCS_ONLY:
                           /* Ignore single-byte results (<0x100). */
                          do {
                              if(((st3&1)!=0 || useFallback) && *((const uint16_t *)stage3)>=0x100) {
                                  sa->add(sa->set, c);
                              }
                              st3>>=1;
                              stage3+=2;  /* +=st3Multiplier */
                          } while((++c&0xf)!=0);
                          break;
                      case UCNV_SET_FILTER_2022_CN:
                           /* Only add code points that map to CNS 11643 planes 1 & 2 for non-EXT ISO-2022-CN. */
                          do {
                              if(((st3&1)!=0 || useFallback) && ((value=*stage3)==0x81 || value==0x82)) {
                                  sa->add(sa->set, c);
                              }
                              st3>>=1;
                              stage3+=3;  /* +=st3Multiplier */
                          } while((++c&0xf)!=0);
                          break;
                      case UCNV_SET_FILTER_SJIS:
                           /* Only add code points that map to Shift-JIS codes corresponding to JIS X 0208. */
                          do {
                              if(((st3&1)!=0 || useFallback) && (value=*((const uint16_t *)stage3))>=0x8140 && value<=0xeffc) {
                                  sa->add(sa->set, c);
                              }
                              st3>>=1;
                              stage3+=2;  /* +=st3Multiplier */
                          } while((++c&0xf)!=0);
                          break;
                      case UCNV_SET_FILTER_GR94DBCS:
                          /* Only add code points that map to ISO 2022 GR 94 DBCS codes (each byte A1..FE). */
                          do {
                              if( ((st3&1)!=0 || useFallback) &&
                                  (uint16_t)((value=*((const uint16_t *)stage3)) - 0xa1a1)<=(0xfefe - 0xa1a1) &&
                                  (uint8_t)(value-0xa1)<=(0xfe - 0xa1)
                              ) {
                                  sa->add(sa->set, c);
                              }
                              st3>>=1;
                              stage3+=2;  /* +=st3Multiplier */
                          } while((++c&0xf)!=0);
                          break;
                      case UCNV_SET_FILTER_HZ:
                          /* Only add code points that are suitable for HZ DBCS (lead byte A1..FD). */
                          do {
                              if( ((st3&1)!=0 || useFallback) &&
                                  (uint16_t)((value=*((const uint16_t *)stage3))-0xa1a1)<=(0xfdfe - 0xa1a1) &&
                                  (uint8_t)(value-0xa1)<=(0xfe - 0xa1)
                              ) {
                                  sa->add(sa->set, c);
                              }
                              st3>>=1;
                              stage3+=2;  /* +=st3Multiplier */
                          } while((++c&0xf)!=0);
                          break;
                      default:
                          *pErrorCode=U_INTERNAL_PROGRAM_ERROR;
                          return;
                      }
                  } else {
                      c+=16; /* empty stage 3 block */
                  }
              }
          } else {
              c+=1024; /* empty stage 2 block */
          }
      }
  }

  ucnv_extGetUnicodeSetucnv_extGetUnicodeSet_71(sharedData, sa, which, filter, pErrorCode);
1059}

1061U_CFUNCextern "C" void
1062ucnv_MBCSGetUnicodeSetForUnicodeucnv_MBCSGetUnicodeSetForUnicode_71(const UConverterSharedData *sharedData,
                               const USetAdder *sa,
                               UConverterUnicodeSet which,
                               UErrorCode *pErrorCode) {
  ucnv_MBCSGetFilteredUnicodeSetForUnicodeucnv_MBCSGetFilteredUnicodeSetForUnicode_71(
      sharedData, sa, which,
      sharedData->mbcs.outputType==MBCS_OUTPUT_DBCS_ONLY ?
          UCNV_SET_FILTER_DBCS_ONLY :
          UCNV_SET_FILTER_NONE,
      pErrorCode);
1072}

1074static void U_CALLCONV
1075ucnv_MBCSGetUnicodeSet(const UConverter *cnv,
                 const USetAdder *sa,
                 UConverterUnicodeSet which,
                 UErrorCode *pErrorCode) {
  if(cnv->options&_MBCS_OPTION_GB180300x8000) {
      sa->addRange(sa->set, 0, 0xd7ff);
      sa->addRange(sa->set, 0xe000, 0x10ffff);
  } else {
      ucnv_MBCSGetUnicodeSetForUnicodeucnv_MBCSGetUnicodeSetForUnicode_71(cnv->sharedData, sa, which, pErrorCode);
  }
1085}

1087/* conversion extensions for input not in the main table -------------------- */

1089/*
* Hardcoded extension handling for GB 18030.
* Definition of LINEAR macros and gb18030Ranges see near the beginning of the file.
*
* In the future, conversion extensions may handle m:n mappings and delta tables,
* see https://htmlpreview.github.io/?https://github.com/unicode-org/icu-docs/blob/main/design/conversion/conversion_extensions.html
*
* If an input character cannot be mapped, then these functions set an error
* code. The framework will then call the callback function.
*/

1100/*
* @return if(U_FAILURE) return the code point for cnv->fromUChar32
*         else return 0 after output has been written to the target
*/
1104static UChar32
1105_extFromU(UConverter *cnv, const UConverterSharedData *sharedData,
        UChar32 cp,
        const UChar **source, const UChar *sourceLimit,
        uint8_t **target, const uint8_t *targetLimit,
        int32_t **offsets, int32_t sourceIndex,
        UBool flush,
        UErrorCode *pErrorCode) {
  const int32_t *cx;

  cnv->useSubChar1=FALSE0;

  if( (cx=sharedData->mbcs.extIndexes)!=NULL__null &&
19
←
Assuming the condition is false→
      ucnv_extInitialMatchFromUucnv_extInitialMatchFromU_71(
          cnv, cx,
          cp, source, sourceLimit,
          (char **)target, (char *)targetLimit,
          offsets, sourceIndex,
          flush,
          pErrorCode)
  ) {
      return 0; /* an extension mapping handled the input */
  }

  /* GB 18030 */
  if((cnv->options&_MBCS_OPTION_GB180300x8000)!=0) {
20
←
Assuming the condition is true→
21
←
Taking true branch→
      const uint32_t *range;
      int32_t i;

      range=gb18030Ranges[0];
      for(i=0; i<UPRV_LENGTHOF(gb18030Ranges)(int32_t)(sizeof(gb18030Ranges)/sizeof((gb18030Ranges)[0])); range+=4, ++i) {
          if(range[0]<=(uint32_t)cp && (uint32_t)cp<=range[1]) {
22
←
Assuming the condition is false→
23
←
The left operand of '<=' is a garbage value
              /* found the Unicode code point, output the four-byte sequence for it */
              uint32_t linear;
              char bytes[4];

              /* get the linear value of the first GB 18030 code in this range */
              linear=range[2]-LINEAR_18030_BASE((((0x81)*10+(0x30))*126L+(0x81))*10L+(0x30));

              /* add the offset from the beginning of the range */
              linear+=((uint32_t)cp-range[0]);

              /* turn this into a four-byte sequence */
              bytes[3]=(char)(0x30+linear%10); linear/=10;
              bytes[2]=(char)(0x81+linear%126); linear/=126;
              bytes[1]=(char)(0x30+linear%10); linear/=10;
              bytes[0]=(char)(0x81+linear);

              /* output this sequence */
              ucnv_fromUWriteBytesucnv_fromUWriteBytes_71(cnv,
                                   bytes, 4, (char **)target, (char *)targetLimit,
                                   offsets, sourceIndex, pErrorCode);
              return 0;
          }
      }
  }

  /* no mapping */
  *pErrorCode=U_INVALID_CHAR_FOUND;
  return cp;
1164}

1166/*
* Input sequence: cnv->toUBytes[0..length[
* @return if(U_FAILURE) return the length (toULength, byteIndex) for the input
*         else return 0 after output has been written to the target
*/
1171static int8_t
1172_extToU(UConverter *cnv, const UConverterSharedData *sharedData,
      int8_t length,
      const uint8_t **source, const uint8_t *sourceLimit,
      UChar **target, const UChar *targetLimit,
      int32_t **offsets, int32_t sourceIndex,
      UBool flush,
      UErrorCode *pErrorCode) {
  const int32_t *cx;

  if( (cx=sharedData->mbcs.extIndexes)!=NULL__null &&
      ucnv_extInitialMatchToUucnv_extInitialMatchToU_71(
          cnv, cx,
          length, (const char **)source, (const char *)sourceLimit,
          target, targetLimit,
          offsets, sourceIndex,
          flush,
          pErrorCode)
  ) {
      return 0; /* an extension mapping handled the input */
  }

  /* GB 18030 */
  if(length==4 && (cnv->options&_MBCS_OPTION_GB180300x8000)!=0) {
      const uint32_t *range;
      uint32_t linear;
      int32_t i;

      linear=LINEAR_18030(cnv->toUBytes[0], cnv->toUBytes[1], cnv->toUBytes[2], cnv->toUBytes[3])((((cnv->toUBytes[0])*10+(cnv->toUBytes[1]))*126L+(cnv->
toUBytes[2]))*10L+(cnv->toUBytes[3]));
      range=gb18030Ranges[0];
      for(i=0; i<UPRV_LENGTHOF(gb18030Ranges)(int32_t)(sizeof(gb18030Ranges)/sizeof((gb18030Ranges)[0])); range+=4, ++i) {
          if(range[2]<=linear && linear<=range[3]) {
              /* found the sequence, output the Unicode code point for it */
              *pErrorCode=U_ZERO_ERROR;

              /* add the linear difference between the input and start sequences to the start code point */
              linear=range[0]+(linear-range[2]);

              /* output this code point */
              ucnv_toUWriteCodePointucnv_toUWriteCodePoint_71(cnv, linear, target, targetLimit, offsets, sourceIndex, pErrorCode);

              return 0;
          }
      }
  }

  /* no mapping */
  *pErrorCode=U_INVALID_CHAR_FOUND;
  return length;
1220}

1222/* EBCDIC swap LF<->NL ------------------------------------------------------ */

1224/*
* This code modifies a standard EBCDIC<->Unicode mapping table for
* OS/390 (z/OS) Unix System Services (Open Edition).
* The difference is in the mapping of Line Feed and New Line control codes:
* Standard EBCDIC maps
*
*   <U000A> \x25 |0
*   <U0085> \x15 |0
*
* but OS/390 USS EBCDIC swaps the control codes for LF and NL,
* mapping
*
*   <U000A> \x15 |0
*   <U0085> \x25 |0
*
* This code modifies a loaded standard EBCDIC<->Unicode mapping table
* by copying it into allocated memory and swapping the LF and NL values.
* It allows to support the same EBCDIC charset in both versions without
* duplicating the entire installed table.
*/

1245/* standard EBCDIC codes */
1246#define EBCDIC_LF0x25 0x25
1247#define EBCDIC_NL0x15 0x15

1249/* standard EBCDIC codes with roundtrip flag as stored in Unicode-to-single-byte tables */
1250#define EBCDIC_RT_LF0xf25 0xf25
1251#define EBCDIC_RT_NL0xf15 0xf15

1253/* Unicode code points */
1254#define U_LF0x0a 0x0a
1255#define U_NL0x85 0x85

1257static UBool
1258_EBCDICSwapLFNL(UConverterSharedData *sharedData, UErrorCode *pErrorCode) {
  UConverterMBCSTable *mbcsTable;

  const uint16_t *table, *results;
  const uint8_t *bytes;

  int32_t (*newStateTable)[256];
  uint16_t *newResults;
  uint8_t *p;
  char *name;

  uint32_t stage2Entry;
  uint32_t size, sizeofFromUBytes;

  mbcsTable=&sharedData->mbcs;

  table=mbcsTable->fromUnicodeTable;
  bytes=mbcsTable->fromUnicodeBytes;
  results=(const uint16_t *)bytes;

  /*
   * Check that this is an EBCDIC table with SBCS portion -
   * SBCS or EBCDIC_STATEFUL with standard EBCDIC LF and NL mappings.
   *
   * If not, ignore the option. Options are always ignored if they do not apply.
   */
  if(!(
       (mbcsTable->outputType==MBCS_OUTPUT_1 || mbcsTable->outputType==MBCS_OUTPUT_2_SISO) &&
       mbcsTable->stateTable[0][EBCDIC_LF0x25]==MBCS_ENTRY_FINAL(0, MBCS_STATE_VALID_DIRECT_16, U_LF)(int32_t)(0x80000000|((int32_t)(0)<<24L)|((MBCS_STATE_VALID_DIRECT_16
)<<20L)|(0x0a)) &&
       mbcsTable->stateTable[0][EBCDIC_NL0x15]==MBCS_ENTRY_FINAL(0, MBCS_STATE_VALID_DIRECT_16, U_NL)(int32_t)(0x80000000|((int32_t)(0)<<24L)|((MBCS_STATE_VALID_DIRECT_16
)<<20L)|(0x85))
  )) {
      return FALSE0;
  }

  if(mbcsTable->outputType==MBCS_OUTPUT_1) {
      if(!(
           EBCDIC_RT_LF0xf25==MBCS_SINGLE_RESULT_FROM_U(table, results, U_LF)(results)[ (table)[ (table)[(0x0a)>>10] +(((0x0a)>>
4)&0x3f) ] +((0x0a)&0xf) ] &&
           EBCDIC_RT_NL0xf15==MBCS_SINGLE_RESULT_FROM_U(table, results, U_NL)(results)[ (table)[ (table)[(0x85)>>10] +(((0x85)>>
4)&0x3f) ] +((0x85)&0xf) ]
      )) {
          return FALSE0;
      }
  } else /* MBCS_OUTPUT_2_SISO */ {
      stage2Entry=MBCS_STAGE_2_FROM_U(table, U_LF)((const uint32_t *)(table))[ (table)[(0x0a)>>10] +(((0x0a
)>>4)&0x3f) ];
      if(!(
           MBCS_FROM_U_IS_ROUNDTRIP(stage2Entry, U_LF)( ((stage2Entry) & ((uint32_t)1<< (16+((0x0a)&0xf
)) )) !=0)!=0 &&
           EBCDIC_LF0x25==MBCS_VALUE_2_FROM_STAGE_2(bytes, stage2Entry, U_LF)((uint16_t *)(bytes))[16*(uint32_t)(uint16_t)(stage2Entry)+((
0x0a)&0xf)]
      )) {
          return FALSE0;
      }

      stage2Entry=MBCS_STAGE_2_FROM_U(table, U_NL)((const uint32_t *)(table))[ (table)[(0x85)>>10] +(((0x85
)>>4)&0x3f) ];
      if(!(
           MBCS_FROM_U_IS_ROUNDTRIP(stage2Entry, U_NL)( ((stage2Entry) & ((uint32_t)1<< (16+((0x85)&0xf
)) )) !=0)!=0 &&
           EBCDIC_NL0x15==MBCS_VALUE_2_FROM_STAGE_2(bytes, stage2Entry, U_NL)((uint16_t *)(bytes))[16*(uint32_t)(uint16_t)(stage2Entry)+((
0x85)&0xf)]
      )) {
          return FALSE0;
      }
  }

  if(mbcsTable->fromUBytesLength>0) {
      /*
       * We _know_ the number of bytes in the fromUnicodeBytes array
       * starting with header.version 4.1.
       */
      sizeofFromUBytes=mbcsTable->fromUBytesLength;
  } else {
      /*
       * Otherwise:
       * There used to be code to enumerate the fromUnicode
       * trie and find the highest entry, but it was removed in ICU 3.2
       * because it was not tested and caused a low code coverage number.
       * See Jitterbug 3674.
       * This affects only some .cnv file formats with a header.version
       * below 4.1, and only when swaplfnl is requested.
       *
       * ucnvmbcs.c revision 1.99 is the last one with the
       * ucnv_MBCSSizeofFromUBytes() function.
       */
      *pErrorCode=U_INVALID_FORMAT_ERROR;
      return FALSE0;
  }

  /*
   * The table has an appropriate format.
   * Allocate and build
   * - a modified to-Unicode state table
   * - a modified from-Unicode output array
   * - a converter name string with the swap option appended
   */
  size=
      mbcsTable->countStates*1024+
      sizeofFromUBytes+
      UCNV_MAX_CONVERTER_NAME_LENGTH60+20;
  p=(uint8_t *)uprv_mallocuprv_malloc_71(size);
  if(p==NULL__null) {
      *pErrorCode=U_MEMORY_ALLOCATION_ERROR;
      return FALSE0;
  }

  /* copy and modify the to-Unicode state table */
  newStateTable=(int32_t (*)[256])p;
  uprv_memcpy(newStateTable, mbcsTable->stateTable, mbcsTable->countStates*1024)do { clang diagnostic push
 clang diagnostic ignored "-Waddress"

 (void)0; (void)0; clang diagnostic pop
 :: memcpy(newStateTable
, mbcsTable->stateTable, mbcsTable->countStates*1024); }
 while (false);

  newStateTable[0][EBCDIC_LF0x25]=MBCS_ENTRY_FINAL(0, MBCS_STATE_VALID_DIRECT_16, U_NL)(int32_t)(0x80000000|((int32_t)(0)<<24L)|((MBCS_STATE_VALID_DIRECT_16
)<<20L)|(0x85));
  newStateTable[0][EBCDIC_NL0x15]=MBCS_ENTRY_FINAL(0, MBCS_STATE_VALID_DIRECT_16, U_LF)(int32_t)(0x80000000|((int32_t)(0)<<24L)|((MBCS_STATE_VALID_DIRECT_16
)<<20L)|(0x0a));

  /* copy and modify the from-Unicode result table */
  newResults=(uint16_t *)newStateTable[mbcsTable->countStates];
  uprv_memcpy(newResults, bytes, sizeofFromUBytes)do { clang diagnostic push
 clang diagnostic ignored "-Waddress"

 (void)0; (void)0; clang diagnostic pop
 :: memcpy(newResults
, bytes, sizeofFromUBytes); } while (false);

  /* conveniently, the table access macros work on the left side of expressions */
  if(mbcsTable->outputType==MBCS_OUTPUT_1) {
      MBCS_SINGLE_RESULT_FROM_U(table, newResults, U_LF)(newResults)[ (table)[ (table)[(0x0a)>>10] +(((0x0a)>>
4)&0x3f) ] +((0x0a)&0xf) ]=EBCDIC_RT_NL0xf15;
      MBCS_SINGLE_RESULT_FROM_U(table, newResults, U_NL)(newResults)[ (table)[ (table)[(0x85)>>10] +(((0x85)>>
4)&0x3f) ] +((0x85)&0xf) ]=EBCDIC_RT_LF0xf25;
  } else /* MBCS_OUTPUT_2_SISO */ {
      stage2Entry=MBCS_STAGE_2_FROM_U(table, U_LF)((const uint32_t *)(table))[ (table)[(0x0a)>>10] +(((0x0a
)>>4)&0x3f) ];
      MBCS_VALUE_2_FROM_STAGE_2(newResults, stage2Entry, U_LF)((uint16_t *)(newResults))[16*(uint32_t)(uint16_t)(stage2Entry
)+((0x0a)&0xf)]=EBCDIC_NL0x15;

      stage2Entry=MBCS_STAGE_2_FROM_U(table, U_NL)((const uint32_t *)(table))[ (table)[(0x85)>>10] +(((0x85
)>>4)&0x3f) ];
      MBCS_VALUE_2_FROM_STAGE_2(newResults, stage2Entry, U_NL)((uint16_t *)(newResults))[16*(uint32_t)(uint16_t)(stage2Entry
)+((0x85)&0xf)]=EBCDIC_LF0x25;
  }

  /* set the canonical converter name */
  name=(char *)newResults+sizeofFromUBytes;
  uprv_strcpy(name, sharedData->staticData->name):: strcpy(name, sharedData->staticData->name);
  uprv_strcat(name, UCNV_SWAP_LFNL_OPTION_STRING):: strcat(name, ",swaplfnl");

  /* set the pointers */
  icu::umtx_lockumtx_lock_71(NULL__null);
  if(mbcsTable->swapLFNLStateTable==NULL__null) {
      mbcsTable->swapLFNLStateTable=newStateTable;
      mbcsTable->swapLFNLFromUnicodeBytes=(uint8_t *)newResults;
      mbcsTable->swapLFNLName=name;

      newStateTable=NULL__null;
  }
  icu::umtx_unlockumtx_unlock_71(NULL__null);

  /* release the allocated memory if another thread beat us to it */
  if(newStateTable!=NULL__null) {
      uprv_freeuprv_free_71(newStateTable);
  }
  return TRUE1;
1401}

1403/* reconstitute omitted fromUnicode data ------------------------------------ */

1405/* for details, compare with genmbcs.c MBCSAddFromUnicode() and transformEUC() */
1406static UBool U_CALLCONV
1407writeStage3Roundtrip(const void *context, uint32_t value, UChar32 codePoints[32]) {
  UConverterMBCSTable *mbcsTable=(UConverterMBCSTable *)context;
  const uint16_t *table;
  uint32_t *stage2;
  uint8_t *bytes, *p;
  UChar32 c;
  int32_t i, st3;

  table=mbcsTable->fromUnicodeTable;
  bytes=(uint8_t *)mbcsTable->fromUnicodeBytes;

  /* for EUC outputTypes, modify the value like genmbcs.c's transformEUC() */
  switch(mbcsTable->outputType) {
  case MBCS_OUTPUT_3_EUC:
      if(value<=0xffff) {
          /* short sequences are stored directly */
          /* code set 0 or 1 */
      } else if(value<=0x8effff) {
          /* code set 2 */
          value&=0x7fff;
      } else /* first byte is 0x8f */ {
          /* code set 3 */
          value&=0xff7f;
      }
      break;
  case MBCS_OUTPUT_4_EUC:
      if(value<=0xffffff) {
          /* short sequences are stored directly */
          /* code set 0 or 1 */
      } else if(value<=0x8effffff) {
          /* code set 2 */
          value&=0x7fffff;
      } else /* first byte is 0x8f */ {
          /* code set 3 */
          value&=0xff7fff;
      }
      break;
  default:
      break;
  }

  for(i=0; i<=0x1f; ++value, ++i) {
      c=codePoints[i];
      if(c<0) {
          continue;
      }

      /* locate the stage 2 & 3 data */
      stage2=((uint32_t *)table)+table[c>>10]+((c>>4)&0x3f);
      p=bytes;
      st3=(int32_t)(uint16_t)*stage2*16+(c&0xf);

      /* write the codepage bytes into stage 3 */
      switch(mbcsTable->outputType) {
      case MBCS_OUTPUT_3:
      case MBCS_OUTPUT_4_EUC:
          p+=st3*3;
          p[0]=(uint8_t)(value>>16);
          p[1]=(uint8_t)(value>>8);
          p[2]=(uint8_t)value;
          break;
      case MBCS_OUTPUT_4:
          ((uint32_t *)p)[st3]=value;
          break;
      default:
          /* 2 bytes per character */
          ((uint16_t *)p)[st3]=(uint16_t)value;
          break;
      }

      /* set the roundtrip flag */
      *stage2|=(1UL<<(16+(c&0xf)));
  }
  return TRUE1;
}

1483static void
1484reconstituteData(UConverterMBCSTable *mbcsTable,
               uint32_t stage1Length, uint32_t stage2Length,
               uint32_t fullStage2Length,  /* lengths are numbers of units, not bytes */
               UErrorCode *pErrorCode) {
  uint16_t *stage1;
  uint32_t *stage2;
  uint32_t dataLength=stage1Length*2+fullStage2Length*4+mbcsTable->fromUBytesLength;
  mbcsTable->reconstitutedData=(uint8_t *)uprv_mallocuprv_malloc_71(dataLength);
  if(mbcsTable->reconstitutedData==NULL__null) {
      *pErrorCode=U_MEMORY_ALLOCATION_ERROR;
      return;
  }
  uprv_memset(mbcsTable->reconstitutedData, 0, dataLength):: memset(mbcsTable->reconstitutedData, 0, dataLength);

  /* copy existing data and reroute the pointers */
  stage1=(uint16_t *)mbcsTable->reconstitutedData;
  uprv_memcpy(stage1, mbcsTable->fromUnicodeTable, stage1Length*2)do { clang diagnostic push
 clang diagnostic ignored "-Waddress"

 (void)0; (void)0; clang diagnostic pop
 :: memcpy(stage1, mbcsTable
->fromUnicodeTable, stage1Length*2); } while (false);

  stage2=(uint32_t *)(stage1+stage1Length);
  uprv_memcpy(stage2+(fullStage2Length-stage2Length),do { clang diagnostic push
 clang diagnostic ignored "-Waddress"

 (void)0; (void)0; clang diagnostic pop
 :: memcpy(stage2+(fullStage2Length
-stage2Length), mbcsTable->fromUnicodeTable+stage1Length, stage2Length
*4); } while (false)
              mbcsTable->fromUnicodeTable+stage1Length,do { clang diagnostic push
 clang diagnostic ignored "-Waddress"

 (void)0; (void)0; clang diagnostic pop
 :: memcpy(stage2+(fullStage2Length
-stage2Length), mbcsTable->fromUnicodeTable+stage1Length, stage2Length
*4); } while (false)
              stage2Length*4)do { clang diagnostic push
 clang diagnostic ignored "-Waddress"

 (void)0; (void)0; clang diagnostic pop
 :: memcpy(stage2+(fullStage2Length
-stage2Length), mbcsTable->fromUnicodeTable+stage1Length, stage2Length
*4); } while (false);

  mbcsTable->fromUnicodeTable=stage1;
  mbcsTable->fromUnicodeBytes=(uint8_t *)(stage2+fullStage2Length);

  /* indexes into stage 2 count from the bottom of the fromUnicodeTable */
  stage2=(uint32_t *)stage1;

  /* reconstitute the initial part of stage 2 from the mbcsIndex */
  {
      int32_t stageUTF8Length=((int32_t)mbcsTable->maxFastUChar+1)>>6;
      int32_t stageUTF8Index=0;
      int32_t st1, st2, st3, i;

      for(st1=0; stageUTF8Index<stageUTF8Length; ++st1) {
          st2=stage1[st1];
          if(st2!=(int32_t)stage1Length/2) {
              /* each stage 2 block has 64 entries corresponding to 16 entries in the mbcsIndex */
              for(i=0; i<16; ++i) {
                  st3=mbcsTable->mbcsIndex[stageUTF8Index++];
                  if(st3!=0) {
                      /* an stage 2 entry's index is per stage 3 16-block, not per stage 3 entry */
                      st3>>=4;
                      /*
                       * 4 stage 2 entries point to 4 consecutive stage 3 16-blocks which are
                       * allocated together as a single 64-block for access from the mbcsIndex
                       */
                      stage2[st2++]=st3++;
                      stage2[st2++]=st3++;
                      stage2[st2++]=st3++;
                      stage2[st2++]=st3;
                  } else {
                      /* no stage 3 block, skip */
                      st2+=4;
                  }
              }
          } else {
              /* no stage 2 block, skip */
              stageUTF8Index+=16;
          }
      }
  }

  /* reconstitute fromUnicodeBytes with roundtrips from toUnicode data */
  ucnv_MBCSEnumToUnicode(mbcsTable, writeStage3Roundtrip, mbcsTable, pErrorCode);
1550}

1552/* MBCS setup functions ----------------------------------------------------- */

1554static void U_CALLCONV
1555ucnv_MBCSLoad(UConverterSharedData *sharedData,
        UConverterLoadArgs *pArgs,
        const uint8_t *raw,
        UErrorCode *pErrorCode) {
  UDataInfo info;
  UConverterMBCSTable *mbcsTable=&sharedData->mbcs;
  _MBCSHeader *header=(_MBCSHeader *)raw;
  uint32_t offset;
  uint32_t headerLength;
  UBool noFromU=FALSE0;

  if(header->version[0]==4) {
      headerLength=MBCS_HEADER_V4_LENGTH;
  } else if(header->version[0]==5 && header->version[1]>=3 &&
            (header->options&MBCS_OPT_UNKNOWN_INCOMPATIBLE_MASK)==0) {
      headerLength=header->options&MBCS_OPT_LENGTH_MASK;
      noFromU=(UBool)((header->options&MBCS_OPT_NO_FROM_U)!=0);
  } else {
      *pErrorCode=U_INVALID_TABLE_FORMAT;
      return;
  }

  mbcsTable->outputType=(uint8_t)header->flags;
  if(noFromU && mbcsTable->outputType==MBCS_OUTPUT_1) {
      *pErrorCode=U_INVALID_TABLE_FORMAT;
      return;
  }

  /* extension data, header version 4.2 and higher */
  offset=header->flags>>8;
  if(offset!=0) {
      mbcsTable->extIndexes=(const int32_t *)(raw+offset);
  }

  if(mbcsTable->outputType==MBCS_OUTPUT_EXT_ONLY) {
      UConverterLoadArgs args=UCNV_LOAD_ARGS_INITIALIZER{ (int32_t)sizeof(UConverterLoadArgs), 0, false, false, 0, 0,
 __null, __null, __null };
      UConverterSharedData *baseSharedData;
      const int32_t *extIndexes;
      const char *baseName;

      /* extension-only file, load the base table and set values appropriately */
      if((extIndexes=mbcsTable->extIndexes)==NULL__null) {
          /* extension-only file without extension */
          *pErrorCode=U_INVALID_TABLE_FORMAT;
          return;
      }

      if(pArgs->nestedLoads!=1) {
          /* an extension table must not be loaded as a base table */
          *pErrorCode=U_INVALID_TABLE_FILE;
          return;
      }

      /* load the base table */
      baseName=(const char *)header+headerLength*4;
      if(0==uprv_strcmp(baseName, sharedData->staticData->name):: strcmp(baseName, sharedData->staticData->name)) {
          /* forbid loading this same extension-only file */
          *pErrorCode=U_INVALID_TABLE_FORMAT;
          return;
      }

      /* TODO parse package name out of the prefix of the base name in the extension .cnv file? */
      args.size=sizeof(UConverterLoadArgs);
      args.nestedLoads=2;
      args.onlyTestIsLoadable=pArgs->onlyTestIsLoadable;
      args.reserved=pArgs->reserved;
      args.options=pArgs->options;
      args.pkg=pArgs->pkg;
      args.name=baseName;
      baseSharedData=ucnv_loaducnv_load_71(&args, pErrorCode);
      if(U_FAILURE(*pErrorCode)) {
          return;
      }
      if( baseSharedData->staticData->conversionType!=UCNV_MBCS ||
          baseSharedData->mbcs.baseSharedData!=NULL__null
      ) {
          ucnv_unloaducnv_unload_71(baseSharedData);
          *pErrorCode=U_INVALID_TABLE_FORMAT;
          return;
      }
      if(pArgs->onlyTestIsLoadable) {
          /*
           * Exit as soon as we know that we can load the converter
           * and the format is valid and supported.
           * The worst that can happen in the following code is a memory
           * allocation error.
           */
          ucnv_unloaducnv_unload_71(baseSharedData);
          return;
      }

      /* copy the base table data */
      uprv_memcpy(mbcsTable, &baseSharedData->mbcs, sizeof(UConverterMBCSTable))do { clang diagnostic push
 clang diagnostic ignored "-Waddress"

 (void)0; (void)0; clang diagnostic pop
 :: memcpy(mbcsTable
, &baseSharedData->mbcs, sizeof(UConverterMBCSTable));
 } while (false);

      /* overwrite values with relevant ones for the extension converter */
      mbcsTable->baseSharedData=baseSharedData;
      mbcsTable->extIndexes=extIndexes;

      /*
       * It would be possible to share the swapLFNL data with a base converter,
       * but the generated name would have to be different, and the memory
       * would have to be free'd only once.
       * It is easier to just create the data for the extension converter
       * separately when it is requested.
       */
      mbcsTable->swapLFNLStateTable=NULL__null;
      mbcsTable->swapLFNLFromUnicodeBytes=NULL__null;
      mbcsTable->swapLFNLName=NULL__null;

      /*
       * The reconstitutedData must be deleted only when the base converter
       * is unloaded.
       */
      mbcsTable->reconstitutedData=NULL__null;

      /*
       * Set a special, runtime-only outputType if the extension converter
       * is a DBCS version of a base converter that also maps single bytes.
       */
      if( sharedData->staticData->conversionType==UCNV_DBCS ||
              (sharedData->staticData->conversionType==UCNV_MBCS &&
               sharedData->staticData->minBytesPerChar>=2)
      ) {
          if(baseSharedData->mbcs.outputType==MBCS_OUTPUT_2_SISO) {
              /* the base converter is SI/SO-stateful */
              int32_t entry;

              /* get the dbcs state from the state table entry for SO=0x0e */
              entry=mbcsTable->stateTable[0][0xe];
              if( MBCS_ENTRY_IS_FINAL(entry)((entry)<0) &&
                  MBCS_ENTRY_FINAL_ACTION(entry)((((uint32_t)entry)>>20)&0xf)==MBCS_STATE_CHANGE_ONLY &&
                  MBCS_ENTRY_FINAL_STATE(entry)((((uint32_t)entry)>>24)&0x7f)!=0
              ) {
                  mbcsTable->dbcsOnlyState=(uint8_t)MBCS_ENTRY_FINAL_STATE(entry)((((uint32_t)entry)>>24)&0x7f);

                  mbcsTable->outputType=MBCS_OUTPUT_DBCS_ONLY;
              }
          } else if(
              baseSharedData->staticData->conversionType==UCNV_MBCS &&
              baseSharedData->staticData->minBytesPerChar==1 &&
              baseSharedData->staticData->maxBytesPerChar==2 &&
              mbcsTable->countStates<=127
          ) {
              /* non-stateful base converter, need to modify the state table */
              int32_t (*newStateTable)[256];
              int32_t *state;
              int32_t i, count;

              /* allocate a new state table and copy the base state table contents */
              count=mbcsTable->countStates;
              newStateTable=(int32_t (*)[256])uprv_mallocuprv_malloc_71((count+1)*1024);
              if(newStateTable==NULL__null) {
                  ucnv_unloaducnv_unload_71(baseSharedData);
                  *pErrorCode=U_MEMORY_ALLOCATION_ERROR;
                  return;
              }

              uprv_memcpy(newStateTable, mbcsTable->stateTable, count*1024)do { clang diagnostic push
 clang diagnostic ignored "-Waddress"

 (void)0; (void)0; clang diagnostic pop
 :: memcpy(newStateTable
, mbcsTable->stateTable, count*1024); } while (false);

              /* change all final single-byte entries to go to a new all-illegal state */
              state=newStateTable[0];
              for(i=0; i<256; ++i) {
                  if(MBCS_ENTRY_IS_FINAL(state[i])((state[i])<0)) {
                      state[i]=MBCS_ENTRY_TRANSITION(count, 0)(int32_t)(((int32_t)(count)<<24L)|(0));
                  }
              }

              /* build the new all-illegal state */
              state=newStateTable[count];
              for(i=0; i<256; ++i) {
                  state[i]=MBCS_ENTRY_FINAL(0, MBCS_STATE_ILLEGAL, 0)(int32_t)(0x80000000|((int32_t)(0)<<24L)|((MBCS_STATE_ILLEGAL
)<<20L)|(0));
              }
              mbcsTable->stateTable=(const int32_t (*)[256])newStateTable;
              mbcsTable->countStates=(uint8_t)(count+1);
              mbcsTable->stateTableOwned=TRUE1;

              mbcsTable->outputType=MBCS_OUTPUT_DBCS_ONLY;
          }
      }

      /*
       * unlike below for files with base tables, do not get the unicodeMask
       * from the sharedData; instead, use the base table's unicodeMask,
       * which we copied in the memcpy above;
       * this is necessary because the static data unicodeMask, especially
       * the UCNV_HAS_SUPPLEMENTARY flag, is part of the base table data
       */
  } else {
      /* conversion file with a base table; an additional extension table is optional */
      /* make sure that the output type is known */
      switch(mbcsTable->outputType) {
      case MBCS_OUTPUT_1:
      case MBCS_OUTPUT_2:
      case MBCS_OUTPUT_3:
      case MBCS_OUTPUT_4:
      case MBCS_OUTPUT_3_EUC:
      case MBCS_OUTPUT_4_EUC:
      case MBCS_OUTPUT_2_SISO:
          /* OK */
          break;
      default:
          *pErrorCode=U_INVALID_TABLE_FORMAT;
          return;
      }
      if(pArgs->onlyTestIsLoadable) {
          /*
           * Exit as soon as we know that we can load the converter
           * and the format is valid and supported.
           * The worst that can happen in the following code is a memory
           * allocation error.
           */
          return;
      }

      mbcsTable->countStates=(uint8_t)header->countStates;
      mbcsTable->countToUFallbacks=header->countToUFallbacks;
      mbcsTable->stateTable=(const int32_t (*)[256])(raw+headerLength*4);
      mbcsTable->toUFallbacks=(const _MBCSToUFallback *)(mbcsTable->stateTable+header->countStates);
      mbcsTable->unicodeCodeUnits=(const uint16_t *)(raw+header->offsetToUCodeUnits);

      mbcsTable->fromUnicodeTable=(const uint16_t *)(raw+header->offsetFromUTable);
      mbcsTable->fromUnicodeBytes=(const uint8_t *)(raw+header->offsetFromUBytes);
      mbcsTable->fromUBytesLength=header->fromUBytesLength;

      /*
       * converter versions 6.1 and up contain a unicodeMask that is
       * used here to select the most efficient function implementations
       */
      info.size=sizeof(UDataInfo);
      udata_getInfoudata_getInfo_71((UDataMemory *)sharedData->dataMemory, &info);
      if(info.formatVersion[0]>6 || (info.formatVersion[0]==6 && info.formatVersion[1]>=1)) {
          /* mask off possible future extensions to be safe */
          mbcsTable->unicodeMask=(uint8_t)(sharedData->staticData->unicodeMask&3);
      } else {
          /* for older versions, assume worst case: contains anything possible (prevent over-optimizations) */
          mbcsTable->unicodeMask=UCNV_HAS_SUPPLEMENTARY1|UCNV_HAS_SURROGATES2;
      }

      /*
       * _MBCSHeader.version 4.3 adds utf8Friendly data structures.
       * Check for the header version, SBCS vs. MBCS, and for whether the
       * data structures are optimized for code points as high as what the
       * runtime code is designed for.
       * The implementation does not handle mapping tables with entries for
       * unpaired surrogates.
       */
      if( header->version[1]>=3 &&
          (mbcsTable->unicodeMask&UCNV_HAS_SURROGATES2)==0 &&
          (mbcsTable->countStates==1 ?
              (header->version[2]>=(SBCS_FAST_MAX>>8)) :
              (header->version[2]>=(MBCS_FAST_MAX>>8))
          )
      ) {
          mbcsTable->utf8Friendly=TRUE1;

          if(mbcsTable->countStates==1) {
              /*
               * SBCS: Stage 3 is allocated in 64-entry blocks for U+0000..SBCS_FAST_MAX or higher.
               * Build a table with indexes to each block, to be used instead of
               * the regular stage 1/2 table.
               */
              int32_t i;
              for(i=0; i<(SBCS_FAST_LIMIT>>6); ++i) {
                  mbcsTable->sbcsIndex[i]=mbcsTable->fromUnicodeTable[mbcsTable->fromUnicodeTable[i>>4]+((i<<2)&0x3c)];
              }
              /* set SBCS_FAST_MAX to reflect the reach of sbcsIndex[] even if header->version[2]>(SBCS_FAST_MAX>>8) */
              mbcsTable->maxFastUChar=SBCS_FAST_MAX;
          } else {
              /*
               * MBCS: Stage 3 is allocated in 64-entry blocks for U+0000..MBCS_FAST_MAX or higher.
               * The .cnv file is prebuilt with an additional stage table with indexes
               * to each block.
               */
              mbcsTable->mbcsIndex=(const uint16_t *)
                  (mbcsTable->fromUnicodeBytes+
                   (noFromU ? 0 : mbcsTable->fromUBytesLength));
              mbcsTable->maxFastUChar=(((UChar)header->version[2])<<8)|0xff;
          }
      }

      /* calculate a bit set of 4 ASCII characters per bit that round-trip to ASCII bytes */
      {
          uint32_t asciiRoundtrips=0xffffffff;
          int32_t i;

          for(i=0; i<0x80; ++i) {
              if(mbcsTable->stateTable[0][i]!=MBCS_ENTRY_FINAL(0, MBCS_STATE_VALID_DIRECT_16, i)(int32_t)(0x80000000|((int32_t)(0)<<24L)|((MBCS_STATE_VALID_DIRECT_16
)<<20L)|(i))) {
                  asciiRoundtrips&=~((uint32_t)1<<(i>>2));
              }
          }
          mbcsTable->asciiRoundtrips=asciiRoundtrips;
      }

      if(noFromU) {
          uint32_t stage1Length=
              mbcsTable->unicodeMask&UCNV_HAS_SUPPLEMENTARY1 ?
                  0x440 : 0x40;
          uint32_t stage2Length=
              (header->offsetFromUBytes-header->offsetFromUTable)/4-
              stage1Length/2;
          reconstituteData(mbcsTable, stage1Length, stage2Length, header->fullStage2Length, pErrorCode);
      }
  }

  /* Set the impl pointer here so that it is set for both extension-only and base tables. */
  if(mbcsTable->utf8Friendly) {
      if(mbcsTable->countStates==1) {
          sharedData->impl=&_SBCSUTF8Impl;
      } else {
          if(mbcsTable->outputType==MBCS_OUTPUT_2) {
              sharedData->impl=&_DBCSUTF8Impl;
          }
      }
  }

  if(mbcsTable->outputType==MBCS_OUTPUT_DBCS_ONLY || mbcsTable->outputType==MBCS_OUTPUT_2_SISO) {
      /*
       * MBCS_OUTPUT_DBCS_ONLY: No SBCS mappings, therefore ASCII does not roundtrip.
       * MBCS_OUTPUT_2_SISO: Bypass the ASCII fastpath to handle prevLength correctly.
       */
      mbcsTable->asciiRoundtrips=0;
  }
1877}

1879static void U_CALLCONV
1880ucnv_MBCSUnload(UConverterSharedData *sharedData) {
  UConverterMBCSTable *mbcsTable=&sharedData->mbcs;

  if(mbcsTable->swapLFNLStateTable!=NULL__null) {
      uprv_freeuprv_free_71(mbcsTable->swapLFNLStateTable);
  }
  if(mbcsTable->stateTableOwned) {
      uprv_freeuprv_free_71((void *)mbcsTable->stateTable);
  }
  if(mbcsTable->baseSharedData!=NULL__null) {
      ucnv_unloaducnv_unload_71(mbcsTable->baseSharedData);
  }
  if(mbcsTable->reconstitutedData!=NULL__null) {
      uprv_freeuprv_free_71(mbcsTable->reconstitutedData);
  }
1895}

1897static void U_CALLCONV
1898ucnv_MBCSOpen(UConverter *cnv,
            UConverterLoadArgs *pArgs,
            UErrorCode *pErrorCode) {
  UConverterMBCSTable *mbcsTable;
  const int32_t *extIndexes;
  uint8_t outputType;
  int8_t maxBytesPerUChar;

  if(pArgs->onlyTestIsLoadable) {
      return;
  }

  mbcsTable=&cnv->sharedData->mbcs;
  outputType=mbcsTable->outputType;

  if(outputType==MBCS_OUTPUT_DBCS_ONLY) {
      /* the swaplfnl option does not apply, remove it */
      cnv->options=pArgs->options&=~UCNV_OPTION_SWAP_LFNL0x10;
  }

  if((pArgs->options&UCNV_OPTION_SWAP_LFNL0x10)!=0) {
      /* do this because double-checked locking is broken */
      UBool isCached;

      icu::umtx_lockumtx_lock_71(NULL__null);
      isCached=mbcsTable->swapLFNLStateTable!=NULL__null;
      icu::umtx_unlockumtx_unlock_71(NULL__null);

      if(!isCached) {
          if(!_EBCDICSwapLFNL(cnv->sharedData, pErrorCode)) {
              if(U_FAILURE(*pErrorCode)) {
                  return; /* something went wrong */
              }

              /* the option does not apply, remove it */
              cnv->options=pArgs->options&=~UCNV_OPTION_SWAP_LFNL0x10;
          }
      }
  }

  if(uprv_strstr(pArgs->name, "18030"):: strstr(pArgs->name, "18030")!=NULL__null) {
      if(uprv_strstr(pArgs->name, "gb18030"):: strstr(pArgs->name, "gb18030")!=NULL__null || uprv_strstr(pArgs->name, "GB18030"):: strstr(pArgs->name, "GB18030")!=NULL__null) {
          /* set a flag for GB 18030 mode, which changes the callback behavior */
          cnv->options|=_MBCS_OPTION_GB180300x8000;
      }
  } else if((uprv_strstr(pArgs->name, "KEIS"):: strstr(pArgs->name, "KEIS")!=NULL__null) || (uprv_strstr(pArgs->name, "keis"):: strstr(pArgs->name, "keis")!=NULL__null)) {
      /* set a flag for KEIS converter, which changes the SI/SO character sequence */
      cnv->options|=_MBCS_OPTION_KEIS0x01000;
  } else if((uprv_strstr(pArgs->name, "JEF"):: strstr(pArgs->name, "JEF")!=NULL__null) || (uprv_strstr(pArgs->name, "jef"):: strstr(pArgs->name, "jef")!=NULL__null)) {
      /* set a flag for JEF converter, which changes the SI/SO character sequence */
      cnv->options|=_MBCS_OPTION_JEF0x02000;
  } else if((uprv_strstr(pArgs->name, "JIPS"):: strstr(pArgs->name, "JIPS")!=NULL__null) || (uprv_strstr(pArgs->name, "jips"):: strstr(pArgs->name, "jips")!=NULL__null)) {
      /* set a flag for JIPS converter, which changes the SI/SO character sequence */
      cnv->options|=_MBCS_OPTION_JIPS0x04000;
  }

  /* fix maxBytesPerUChar depending on outputType and options etc. */
  if(outputType==MBCS_OUTPUT_2_SISO) {
      cnv->maxBytesPerUChar=3; /* SO+DBCS */
  }

  extIndexes=mbcsTable->extIndexes;
  if(extIndexes!=NULL__null) {
      maxBytesPerUChar=(int8_t)UCNV_GET_MAX_BYTES_PER_UCHAR(extIndexes)((extIndexes)[UCNV_EXT_COUNT_BYTES]&0xff);
      if(outputType==MBCS_OUTPUT_2_SISO) {
          ++maxBytesPerUChar; /* SO + multiple DBCS */
      }

      if(maxBytesPerUChar>cnv->maxBytesPerUChar) {
          cnv->maxBytesPerUChar=maxBytesPerUChar;
      }
  }

1971#if 0
  /*
   * documentation of UConverter fields used for status
   * all of these fields are (re)set to 0 by ucnv_bld.c and ucnv_reset()
   */

  /* toUnicode */
  cnv->toUnicodeStatus=0;     /* offset */
  cnv->mode=0;                /* state */
  cnv->toULength=0;           /* byteIndex */

  /* fromUnicode */
  cnv->fromUChar32=0;
  cnv->fromUnicodeStatus=1;   /* prevLength */
1985#endif
1986}

1988U_CDECL_BEGINextern "C" {

1990static const char* U_CALLCONV
1991ucnv_MBCSGetName(const UConverter *cnv) {
  if((cnv->options&UCNV_OPTION_SWAP_LFNL0x10)!=0 && cnv->sharedData->mbcs.swapLFNLName!=NULL__null) {
      return cnv->sharedData->mbcs.swapLFNLName;
  } else {
      return cnv->sharedData->staticData->name;
  }
1997}
1998U_CDECL_END}


2001/* MBCS-to-Unicode conversion functions ------------------------------------- */

2003static UChar32 U_CALLCONV
2004ucnv_MBCSGetFallback(UConverterMBCSTable *mbcsTable, uint32_t offset) {
  const _MBCSToUFallback *toUFallbacks;
  uint32_t i, start, limit;

  limit=mbcsTable->countToUFallbacks;
  if(limit>0) {
      /* do a binary search for the fallback mapping */
      toUFallbacks=mbcsTable->toUFallbacks;
      start=0;
      while(start<limit-1) {
          i=(start+limit)/2;
          if(offset<toUFallbacks[i].offset) {
              limit=i;
          } else {
              start=i;
          }
      }

      /* did we really find it? */
      if(offset==toUFallbacks[start].offset) {
          return toUFallbacks[start].codePoint;
      }
  }

  return 0xfffe;
2029}

2031/* This version of ucnv_MBCSToUnicodeWithOffsets() is optimized for single-byte, single-state codepages. */
2032static void
2033ucnv_MBCSSingleToUnicodeWithOffsets(UConverterToUnicodeArgs *pArgs,
                              UErrorCode *pErrorCode) {
  UConverter *cnv;
  const uint8_t *source, *sourceLimit;
  UChar *target;
  const UChar *targetLimit;
  int32_t *offsets;

  const int32_t (*stateTable)[256];

  int32_t sourceIndex;

  int32_t entry;
  UChar c;
  uint8_t action;

  /* set up the local pointers */
  cnv=pArgs->converter;
  source=(const uint8_t *)pArgs->source;
  sourceLimit=(const uint8_t *)pArgs->sourceLimit;
  target=pArgs->target;
  targetLimit=pArgs->targetLimit;
  offsets=pArgs->offsets;

  if((cnv->options&UCNV_OPTION_SWAP_LFNL0x10)!=0) {
      stateTable=(const int32_t (*)[256])cnv->sharedData->mbcs.swapLFNLStateTable;
  } else {
      stateTable=cnv->sharedData->mbcs.stateTable;
  }

  /* sourceIndex=-1 if the current character began in the previous buffer */
  sourceIndex=0;

  /* conversion loop */
  while(source<sourceLimit) {
      /*
       * This following test is to see if available input would overflow the output.
       * It does not catch output of more than one code unit that
       * overflows as a result of a surrogate pair or callback output
       * from the last source byte.
       * Therefore, those situations also test for overflows and will
       * then break the loop, too.
       */
      if(target>=targetLimit) {
          /* target is full */
          *pErrorCode=U_BUFFER_OVERFLOW_ERROR;
          break;
      }

      entry=stateTable[0][*source++];
      /* MBCS_ENTRY_IS_FINAL(entry) */

      /* test the most common case first */
      if(MBCS_ENTRY_FINAL_IS_VALID_DIRECT_16(entry)((entry)<(int32_t)0x80100000)) {
          /* output BMP code point */
          *target++=(UChar)MBCS_ENTRY_FINAL_VALUE_16(entry)(uint16_t)(entry);
          if(offsets!=NULL__null) {
              *offsets++=sourceIndex;
          }

          /* normal end of action codes: prepare for a new character */
          ++sourceIndex;
          continue;
      }

      /*
       * An if-else-if chain provides more reliable performance for
       * the most common cases compared to a switch.
       */
      action=(uint8_t)(MBCS_ENTRY_FINAL_ACTION(entry)((((uint32_t)entry)>>20)&0xf));
      if(action==MBCS_STATE_VALID_DIRECT_20 ||
         (action==MBCS_STATE_FALLBACK_DIRECT_20 && UCNV_TO_U_USE_FALLBACK(cnv)true)
      ) {
          entry=MBCS_ENTRY_FINAL_VALUE(entry)((entry)&0xfffff);
          /* output surrogate pair */
          *target++=(UChar)(0xd800|(UChar)(entry>>10));
          if(offsets!=NULL__null) {
              *offsets++=sourceIndex;
          }
          c=(UChar)(0xdc00|(UChar)(entry&0x3ff));
          if(target<targetLimit) {
              *target++=c;
              if(offsets!=NULL__null) {
                  *offsets++=sourceIndex;
              }
          } else {
              /* target overflow */
              cnv->UCharErrorBuffer[0]=c;
              cnv->UCharErrorBufferLength=1;
              *pErrorCode=U_BUFFER_OVERFLOW_ERROR;
              break;
          }

          ++sourceIndex;
          continue;
      } else if(action==MBCS_STATE_FALLBACK_DIRECT_16) {
          if(UCNV_TO_U_USE_FALLBACK(cnv)true) {
              /* output BMP code point */
              *target++=(UChar)MBCS_ENTRY_FINAL_VALUE_16(entry)(uint16_t)(entry);
              if(offsets!=NULL__null) {
                  *offsets++=sourceIndex;
              }

              ++sourceIndex;
              continue;
          }
      } else if(action==MBCS_STATE_UNASSIGNED) {
          /* just fall through */
      } else if(action==MBCS_STATE_ILLEGAL) {
          /* callback(illegal) */
          *pErrorCode=U_ILLEGAL_CHAR_FOUND;
      } else {
          /* reserved, must never occur */
          ++sourceIndex;
          continue;
      }

      if(U_FAILURE(*pErrorCode)) {
          /* callback(illegal) */
          break;
      } else /* unassigned sequences indicated with byteIndex>0 */ {
          /* try an extension mapping */
          pArgs->source=(const char *)source;
          cnv->toUBytes[0]=*(source-1);
          cnv->toULength=_extToU(cnv, cnv->sharedData,
                                  1, &source, sourceLimit,
                                  &target, targetLimit,
                                  &offsets, sourceIndex,
                                  pArgs->flush,
                                  pErrorCode);
          sourceIndex+=1+(int32_t)(source-(const uint8_t *)pArgs->source);

          if(U_FAILURE(*pErrorCode)) {
              /* not mappable or buffer overflow */
              break;
          }
      }
  }

  /* write back the updated pointers */
  pArgs->source=(const char *)source;
  pArgs->target=target;
  pArgs->offsets=offsets;
2176}

2178/*
* This version of ucnv_MBCSSingleToUnicodeWithOffsets() is optimized for single-byte, single-state codepages
* that only map to and from the BMP.
* In addition to single-byte optimizations, the offset calculations
* become much easier.
*/
2184static void
2185ucnv_MBCSSingleToBMPWithOffsets(UConverterToUnicodeArgs *pArgs,
                          UErrorCode *pErrorCode) {
  UConverter *cnv;
  const uint8_t *source, *sourceLimit, *lastSource;
  UChar *target;
  int32_t targetCapacity, length;
  int32_t *offsets;

  const int32_t (*stateTable)[256];

  int32_t sourceIndex;

  int32_t entry;
  uint8_t action;

  /* set up the local pointers */
  cnv=pArgs->converter;
  source=(const uint8_t *)pArgs->source;
  sourceLimit=(const uint8_t *)pArgs->sourceLimit;
  target=pArgs->target;
  targetCapacity=(int32_t)(pArgs->targetLimit-pArgs->target);
  offsets=pArgs->offsets;

  if((cnv->options&UCNV_OPTION_SWAP_LFNL0x10)!=0) {
      stateTable=(const int32_t (*)[256])cnv->sharedData->mbcs.swapLFNLStateTable;
  } else {
      stateTable=cnv->sharedData->mbcs.stateTable;
  }

  /* sourceIndex=-1 if the current character began in the previous buffer */
  sourceIndex=0;
  lastSource=source;

  /*
   * since the conversion here is 1:1 UChar:uint8_t, we need only one counter
   * for the minimum of the sourceLength and targetCapacity
   */
  length=(int32_t)(sourceLimit-source);
  if(length<targetCapacity) {
      targetCapacity=length;
  }

2227#if MBCS_UNROLL_SINGLE_TO_BMP1
  /* unrolling makes it faster on Pentium III/Windows 2000 */
  /* unroll the loop with the most common case */
2230unrolled:
  if(targetCapacity>=16) {
      int32_t count, loops, oredEntries;

      loops=count=targetCapacity>>4;
      do {
          oredEntries=entry=stateTable[0][*source++];
          *target++=(UChar)MBCS_ENTRY_FINAL_VALUE_16(entry)(uint16_t)(entry);
          oredEntries|=entry=stateTable[0][*source++];
          *target++=(UChar)MBCS_ENTRY_FINAL_VALUE_16(entry)(uint16_t)(entry);
          oredEntries|=entry=stateTable[0][*source++];
          *target++=(UChar)MBCS_ENTRY_FINAL_VALUE_16(entry)(uint16_t)(entry);
          oredEntries|=entry=stateTable[0][*source++];
          *target++=(UChar)MBCS_ENTRY_FINAL_VALUE_16(entry)(uint16_t)(entry);
          oredEntries|=entry=stateTable[0][*source++];
          *target++=(UChar)MBCS_ENTRY_FINAL_VALUE_16(entry)(uint16_t)(entry);
          oredEntries|=entry=stateTable[0][*source++];
          *target++=(UChar)MBCS_ENTRY_FINAL_VALUE_16(entry)(uint16_t)(entry);
          oredEntries|=entry=stateTable[0][*source++];
          *target++=(UChar)MBCS_ENTRY_FINAL_VALUE_16(entry)(uint16_t)(entry);
          oredEntries|=entry=stateTable[0][*source++];
          *target++=(UChar)MBCS_ENTRY_FINAL_VALUE_16(entry)(uint16_t)(entry);
          oredEntries|=entry=stateTable[0][*source++];
          *target++=(UChar)MBCS_ENTRY_FINAL_VALUE_16(entry)(uint16_t)(entry);
          oredEntries|=entry=stateTable[0][*source++];
          *target++=(UChar)MBCS_ENTRY_FINAL_VALUE_16(entry)(uint16_t)(entry);
          oredEntries|=entry=stateTable[0][*source++];
          *target++=(UChar)MBCS_ENTRY_FINAL_VALUE_16(entry)(uint16_t)(entry);
          oredEntries|=entry=stateTable[0][*source++];
          *target++=(UChar)MBCS_ENTRY_FINAL_VALUE_16(entry)(uint16_t)(entry);
          oredEntries|=entry=stateTable[0][*source++];
          *target++=(UChar)MBCS_ENTRY_FINAL_VALUE_16(entry)(uint16_t)(entry);
          oredEntries|=entry=stateTable[0][*source++];
          *target++=(UChar)MBCS_ENTRY_FINAL_VALUE_16(entry)(uint16_t)(entry);
          oredEntries|=entry=stateTable[0][*source++];
          *target++=(UChar)MBCS_ENTRY_FINAL_VALUE_16(entry)(uint16_t)(entry);
          oredEntries|=entry=stateTable[0][*source++];
          *target++=(UChar)MBCS_ENTRY_FINAL_VALUE_16(entry)(uint16_t)(entry);

          /* were all 16 entries really valid? */
          if(!MBCS_ENTRY_FINAL_IS_VALID_DIRECT_16(oredEntries)((oredEntries)<(int32_t)0x80100000)) {
              /* no, return to the first of these 16 */
              source-=16;
              target-=16;
              break;
          }
      } while(--count>0);
      count=loops-count;
      targetCapacity-=16*count;

      if(offsets!=NULL__null) {
          lastSource+=16*count;
          while(count>0) {
              *offsets++=sourceIndex++;
              *offsets++=sourceIndex++;
              *offsets++=sourceIndex++;
              *offsets++=sourceIndex++;
              *offsets++=sourceIndex++;
              *offsets++=sourceIndex++;
              *offsets++=sourceIndex++;
              *offsets++=sourceIndex++;
              *offsets++=sourceIndex++;
              *offsets++=sourceIndex++;
              *offsets++=sourceIndex++;
              *offsets++=sourceIndex++;
              *offsets++=sourceIndex++;
              *offsets++=sourceIndex++;
              *offsets++=sourceIndex++;
              *offsets++=sourceIndex++;
              --count;
          }
      }
  }
2303#endif

  /* conversion loop */
  while(targetCapacity > 0 && source < sourceLimit) {
      entry=stateTable[0][*source++];
      /* MBCS_ENTRY_IS_FINAL(entry) */

      /* test the most common case first */
      if(MBCS_ENTRY_FINAL_IS_VALID_DIRECT_16(entry)((entry)<(int32_t)0x80100000)) {
          /* output BMP code point */
          *target++=(UChar)MBCS_ENTRY_FINAL_VALUE_16(entry)(uint16_t)(entry);
          --targetCapacity;
          continue;
      }

      /*
       * An if-else-if chain provides more reliable performance for
       * the most common cases compared to a switch.
       */
      action=(uint8_t)(MBCS_ENTRY_FINAL_ACTION(entry)((((uint32_t)entry)>>20)&0xf));
      if(action==MBCS_STATE_FALLBACK_DIRECT_16) {
          if(UCNV_TO_U_USE_FALLBACK(cnv)true) {
              /* output BMP code point */
              *target++=(UChar)MBCS_ENTRY_FINAL_VALUE_16(entry)(uint16_t)(entry);
              --targetCapacity;
              continue;
          }
      } else if(action==MBCS_STATE_UNASSIGNED) {
          /* just fall through */
      } else if(action==MBCS_STATE_ILLEGAL) {
          /* callback(illegal) */
          *pErrorCode=U_ILLEGAL_CHAR_FOUND;
      } else {
          /* reserved, must never occur */
          continue;
      }

      /* set offsets since the start or the last extension */
      if(offsets!=NULL__null) {
          int32_t count=(int32_t)(source-lastSource);

          /* predecrement: do not set the offset for the callback-causing character */
          while(--count>0) {
              *offsets++=sourceIndex++;
          }
          /* offset and sourceIndex are now set for the current character */
      }

      if(U_FAILURE(*pErrorCode)) {
          /* callback(illegal) */
          break;
      } else /* unassigned sequences indicated with byteIndex>0 */ {
          /* try an extension mapping */
          lastSource=source;
          cnv->toUBytes[0]=*(source-1);
          cnv->toULength=_extToU(cnv, cnv->sharedData,
                                  1, &source, sourceLimit,
                                  &target, pArgs->targetLimit,
                                  &offsets, sourceIndex,
                                  pArgs->flush,
                                  pErrorCode);
          sourceIndex+=1+(int32_t)(source-lastSource);

          if(U_FAILURE(*pErrorCode)) {
              /* not mappable or buffer overflow */
              break;
          }

          /* recalculate the targetCapacity after an extension mapping */
          targetCapacity=(int32_t)(pArgs->targetLimit-target);
          length=(int32_t)(sourceLimit-source);
          if(length<targetCapacity) {
              targetCapacity=length;
          }
      }

2379#if MBCS_UNROLL_SINGLE_TO_BMP1
      /* unrolling makes it faster on Pentium III/Windows 2000 */
      goto unrolled;
2382#endif
  }

  if(U_SUCCESS(*pErrorCode) && source<sourceLimit && target>=pArgs->targetLimit) {
      /* target is full */
      *pErrorCode=U_BUFFER_OVERFLOW_ERROR;
  }

  /* set offsets since the start or the last callback */
  if(offsets!=NULL__null) {
      size_t count=source-lastSource;
      while(count>0) {
          *offsets++=sourceIndex++;
          --count;
      }
  }

  /* write back the updated pointers */
  pArgs->source=(const char *)source;
  pArgs->target=target;
  pArgs->offsets=offsets;
2403}

2405static UBool
2406hasValidTrailBytes(const int32_t (*stateTable)[256], uint8_t state) {
  const int32_t *row=stateTable[state];
  int32_t b, entry;
  /* First test for final entries in this state for some commonly valid byte values. */
  entry=row[0xa1];
  if( !MBCS_ENTRY_IS_TRANSITION(entry)((entry)>=0) &&
      MBCS_ENTRY_FINAL_ACTION(entry)((((uint32_t)entry)>>20)&0xf)!=MBCS_STATE_ILLEGAL
  ) {
      return TRUE1;
  }
  entry=row[0x41];
  if( !MBCS_ENTRY_IS_TRANSITION(entry)((entry)>=0) &&
      MBCS_ENTRY_FINAL_ACTION(entry)((((uint32_t)entry)>>20)&0xf)!=MBCS_STATE_ILLEGAL
  ) {
      return TRUE1;
  }
  /* Then test for final entries in this state. */
  for(b=0; b<=0xff; ++b) {
      entry=row[b];
      if( !MBCS_ENTRY_IS_TRANSITION(entry)((entry)>=0) &&
          MBCS_ENTRY_FINAL_ACTION(entry)((((uint32_t)entry)>>20)&0xf)!=MBCS_STATE_ILLEGAL
      ) {
          return TRUE1;
      }
  }
  /* Then recurse for transition entries. */
  for(b=0; b<=0xff; ++b) {
      entry=row[b];
      if( MBCS_ENTRY_IS_TRANSITION(entry)((entry)>=0) &&
          hasValidTrailBytes(stateTable, (uint8_t)MBCS_ENTRY_TRANSITION_STATE(entry)(((uint32_t)entry)>>24))
      ) {
          return TRUE1;
      }
  }
  return FALSE0;
2441}

2443/*
* Is byte b a single/lead byte in this state?
* Recurse for transition states, because here we don't want to say that
* b is a lead byte if all byte sequences that start with b are illegal.
*/
2448static UBool
2449isSingleOrLead(const int32_t (*stateTable)[256], uint8_t state, UBool isDBCSOnly, uint8_t b) {
  const int32_t *row=stateTable[state];
  int32_t entry=row[b];
  if(MBCS_ENTRY_IS_TRANSITION(entry)((entry)>=0)) {   /* lead byte */
      return hasValidTrailBytes(stateTable, (uint8_t)MBCS_ENTRY_TRANSITION_STATE(entry)(((uint32_t)entry)>>24));
  } else {
      uint8_t action=(uint8_t)(MBCS_ENTRY_FINAL_ACTION(entry)((((uint32_t)entry)>>20)&0xf));
      if(action==MBCS_STATE_CHANGE_ONLY && isDBCSOnly) {
          return FALSE0;   /* SI/SO are illegal for DBCS-only conversion */
      } else {
          return action!=MBCS_STATE_ILLEGAL;
      }
  }
2462}

2464U_CFUNCextern "C" void
2465ucnv_MBCSToUnicodeWithOffsetsucnv_MBCSToUnicodeWithOffsets_71(UConverterToUnicodeArgs *pArgs,
                        UErrorCode *pErrorCode) {
  UConverter *cnv;
  const uint8_t *source, *sourceLimit;
  UChar *target;
  const UChar *targetLimit;
  int32_t *offsets;

  const int32_t (*stateTable)[256];
  const uint16_t *unicodeCodeUnits;

  uint32_t offset;
  uint8_t state;
  int8_t byteIndex;
  uint8_t *bytes;

  int32_t sourceIndex, nextSourceIndex;

  int32_t entry;
  UChar c;
  uint8_t action;

  /* use optimized function if possible */
  cnv=pArgs->converter;

  if(cnv->preToULength>0) {
      /*
       * pass sourceIndex=-1 because we continue from an earlier buffer
       * in the future, this may change with continuous offsets
       */
      ucnv_extContinueMatchToUucnv_extContinueMatchToU_71(cnv, pArgs, -1, pErrorCode);

      if(U_FAILURE(*pErrorCode) || cnv->preToULength<0) {
          return;
      }
  }

  if(cnv->sharedData->mbcs.countStates==1) {
      if(!(cnv->sharedData->mbcs.unicodeMask&UCNV_HAS_SUPPLEMENTARY1)) {
          ucnv_MBCSSingleToBMPWithOffsets(pArgs, pErrorCode);
      } else {
          ucnv_MBCSSingleToUnicodeWithOffsets(pArgs, pErrorCode);
      }
      return;
  }

  /* set up the local pointers */
  source=(const uint8_t *)pArgs->source;
  sourceLimit=(const uint8_t *)pArgs->sourceLimit;
  target=pArgs->target;
  targetLimit=pArgs->targetLimit;
  offsets=pArgs->offsets;

  if((cnv->options&UCNV_OPTION_SWAP_LFNL0x10)!=0) {
      stateTable=(const int32_t (*)[256])cnv->sharedData->mbcs.swapLFNLStateTable;
  } else {
      stateTable=cnv->sharedData->mbcs.stateTable;
  }
  unicodeCodeUnits=cnv->sharedData->mbcs.unicodeCodeUnits;

  /* get the converter state from UConverter */
  offset=cnv->toUnicodeStatus;
  byteIndex=cnv->toULength;
  bytes=cnv->toUBytes;

  /*
   * if we are in the SBCS state for a DBCS-only converter,
   * then load the DBCS state from the MBCS data
   * (dbcsOnlyState==0 if it is not a DBCS-only converter)
   */
  if((state=(uint8_t)(cnv->mode))==0) {
      state=cnv->sharedData->mbcs.dbcsOnlyState;
  }

  /* sourceIndex=-1 if the current character began in the previous buffer */
  sourceIndex=byteIndex==0 ? 0 : -1;
  nextSourceIndex=0;

  /* conversion loop */
  while(source<sourceLimit) {
      /*
       * This following test is to see if available input would overflow the output.
       * It does not catch output of more than one code unit that
       * overflows as a result of a surrogate pair or callback output
       * from the last source byte.
       * Therefore, those situations also test for overflows and will
       * then break the loop, too.
       */
      if(target>=targetLimit) {
          /* target is full */
          *pErrorCode=U_BUFFER_OVERFLOW_ERROR;
          break;
      }

      if(byteIndex==0) {
          /* optimized loop for 1/2-byte input and BMP output */
          if(offsets==NULL__null) {
              do {
                  entry=stateTable[state][*source];
                  if(MBCS_ENTRY_IS_TRANSITION(entry)((entry)>=0)) {
                      state=(uint8_t)MBCS_ENTRY_TRANSITION_STATE(entry)(((uint32_t)entry)>>24);
                      offset=MBCS_ENTRY_TRANSITION_OFFSET(entry)((entry)&0xffffff);

                      ++source;
                      if( source<sourceLimit &&
                          MBCS_ENTRY_IS_FINAL(entry=stateTable[state][*source])((entry=stateTable[state][*source])<0) &&
                          MBCS_ENTRY_FINAL_ACTION(entry)((((uint32_t)entry)>>20)&0xf)==MBCS_STATE_VALID_16 &&
                          (c=unicodeCodeUnits[offset+MBCS_ENTRY_FINAL_VALUE_16(entry)(uint16_t)(entry)])<0xfffe
                      ) {
                          ++source;
                          *target++=c;
                          state=(uint8_t)MBCS_ENTRY_FINAL_STATE(entry)((((uint32_t)entry)>>24)&0x7f); /* typically 0 */
                          offset=0;
                      } else {
                          /* set the state and leave the optimized loop */
                          bytes[0]=*(source-1);
                          byteIndex=1;
                          break;
                      }
                  } else {
                      if(MBCS_ENTRY_FINAL_IS_VALID_DIRECT_16(entry)((entry)<(int32_t)0x80100000)) {
                          /* output BMP code point */
                          ++source;
                          *target++=(UChar)MBCS_ENTRY_FINAL_VALUE_16(entry)(uint16_t)(entry);
                          state=(uint8_t)MBCS_ENTRY_FINAL_STATE(entry)((((uint32_t)entry)>>24)&0x7f); /* typically 0 */
                      } else {
                          /* leave the optimized loop */
                          break;
                      }
                  }
              } while(source<sourceLimit && target<targetLimit);
          } else /* offsets!=NULL */ {
              do {
                  entry=stateTable[state][*source];
                  if(MBCS_ENTRY_IS_TRANSITION(entry)((entry)>=0)) {
                      state=(uint8_t)MBCS_ENTRY_TRANSITION_STATE(entry)(((uint32_t)entry)>>24);
                      offset=MBCS_ENTRY_TRANSITION_OFFSET(entry)((entry)&0xffffff);

                      ++source;
                      if( source<sourceLimit &&
                          MBCS_ENTRY_IS_FINAL(entry=stateTable[state][*source])((entry=stateTable[state][*source])<0) &&
                          MBCS_ENTRY_FINAL_ACTION(entry)((((uint32_t)entry)>>20)&0xf)==MBCS_STATE_VALID_16 &&
                          (c=unicodeCodeUnits[offset+MBCS_ENTRY_FINAL_VALUE_16(entry)(uint16_t)(entry)])<0xfffe
                      ) {
                          ++source;
                          *target++=c;
                          if(offsets!=NULL__null) {
                              *offsets++=sourceIndex;
                              sourceIndex=(nextSourceIndex+=2);
                          }
                          state=(uint8_t)MBCS_ENTRY_FINAL_STATE(entry)((((uint32_t)entry)>>24)&0x7f); /* typically 0 */
                          offset=0;
                      } else {
                          /* set the state and leave the optimized loop */
                          ++nextSourceIndex;
                          bytes[0]=*(source-1);
                          byteIndex=1;
                          break;
                      }
                  } else {
                      if(MBCS_ENTRY_FINAL_IS_VALID_DIRECT_16(entry)((entry)<(int32_t)0x80100000)) {
                          /* output BMP code point */
                          ++source;
                          *target++=(UChar)MBCS_ENTRY_FINAL_VALUE_16(entry)(uint16_t)(entry);
                          if(offsets!=NULL__null) {
                              *offsets++=sourceIndex;
                              sourceIndex=++nextSourceIndex;
                          }
                          state=(uint8_t)MBCS_ENTRY_FINAL_STATE(entry)((((uint32_t)entry)>>24)&0x7f); /* typically 0 */
                      } else {
                          /* leave the optimized loop */
                          break;
                      }
                  }
              } while(source<sourceLimit && target<targetLimit);
          }

          /*
           * these tests and break statements could be put inside the loop
           * if C had "break outerLoop" like Java
           */
          if(source>=sourceLimit) {
              break;
          }
          if(target>=targetLimit) {
              /* target is full */
              *pErrorCode=U_BUFFER_OVERFLOW_ERROR;
              break;
          }

          ++nextSourceIndex;
          bytes[byteIndex++]=*source++;
      } else /* byteIndex>0 */ {
          ++nextSourceIndex;
          entry=stateTable[state][bytes[byteIndex++]=*source++];
      }

      if(MBCS_ENTRY_IS_TRANSITION(entry)((entry)>=0)) {
          state=(uint8_t)MBCS_ENTRY_TRANSITION_STATE(entry)(((uint32_t)entry)>>24);
          offset+=MBCS_ENTRY_TRANSITION_OFFSET(entry)((entry)&0xffffff);
          continue;
      }

      /* save the previous state for proper extension mapping with SI/SO-stateful converters */
      cnv->mode=state;

      /* set the next state early so that we can reuse the entry variable */
      state=(uint8_t)MBCS_ENTRY_FINAL_STATE(entry)((((uint32_t)entry)>>24)&0x7f); /* typically 0 */

      /*
       * An if-else-if chain provides more reliable performance for
       * the most common cases compared to a switch.
       */
      action=(uint8_t)(MBCS_ENTRY_FINAL_ACTION(entry)((((uint32_t)entry)>>20)&0xf));
      if(action==MBCS_STATE_VALID_16) {
          offset+=MBCS_ENTRY_FINAL_VALUE_16(entry)(uint16_t)(entry);
          c=unicodeCodeUnits[offset];
          if(c<0xfffe) {
              /* output BMP code point */
              *target++=c;
              if(offsets!=NULL__null) {
                  *offsets++=sourceIndex;
              }
              byteIndex=0;
          } else if(c==0xfffe) {
              if(UCNV_TO_U_USE_FALLBACK(cnv)true && (entry=(int32_t)ucnv_MBCSGetFallback(&cnv->sharedData->mbcs, offset))!=0xfffe) {
                  /* output fallback BMP code point */
                  *target++=(UChar)entry;
                  if(offsets!=NULL__null) {
                      *offsets++=sourceIndex;
                  }
                  byteIndex=0;
              }
          } else {
              /* callback(illegal) */
              *pErrorCode=U_ILLEGAL_CHAR_FOUND;
          }
      } else if(action==MBCS_STATE_VALID_DIRECT_16) {
          /* output BMP code point */
          *target++=(UChar)MBCS_ENTRY_FINAL_VALUE_16(entry)(uint16_t)(entry);
          if(offsets!=NULL__null) {
              *offsets++=sourceIndex;
          }
          byteIndex=0;
      } else if(action==MBCS_STATE_VALID_16_PAIR) {
          offset+=MBCS_ENTRY_FINAL_VALUE_16(entry)(uint16_t)(entry);
          c=unicodeCodeUnits[offset++];
          if(c<0xd800) {
              /* output BMP code point below 0xd800 */
              *target++=c;
              if(offsets!=NULL__null) {
                  *offsets++=sourceIndex;
              }
              byteIndex=0;
          } else if(UCNV_TO_U_USE_FALLBACK(cnv)true ? c<=0xdfff : c<=0xdbff) {
              /* output roundtrip or fallback surrogate pair */
              *target++=(UChar)(c&0xdbff);
              if(offsets!=NULL__null) {
                  *offsets++=sourceIndex;
              }
              byteIndex=0;
              if(target<targetLimit) {
                  *target++=unicodeCodeUnits[offset];
                  if(offsets!=NULL__null) {
                      *offsets++=sourceIndex;
                  }
              } else {
                  /* target overflow */
                  cnv->UCharErrorBuffer[0]=unicodeCodeUnits[offset];
                  cnv->UCharErrorBufferLength=1;
                  *pErrorCode=U_BUFFER_OVERFLOW_ERROR;

                  offset=0;
                  break;
              }
          } else if(UCNV_TO_U_USE_FALLBACK(cnv)true ? (c&0xfffe)==0xe000 : c==0xe000) {
              /* output roundtrip BMP code point above 0xd800 or fallback BMP code point */
              *target++=unicodeCodeUnits[offset];
              if(offsets!=NULL__null) {
                  *offsets++=sourceIndex;
              }
              byteIndex=0;
          } else if(c==0xffff) {
              /* callback(illegal) */
              *pErrorCode=U_ILLEGAL_CHAR_FOUND;
          }
      } else if(action==MBCS_STATE_VALID_DIRECT_20 ||
                (action==MBCS_STATE_FALLBACK_DIRECT_20 && UCNV_TO_U_USE_FALLBACK(cnv)true)
      ) {
          entry=MBCS_ENTRY_FINAL_VALUE(entry)((entry)&0xfffff);
          /* output surrogate pair */
          *target++=(UChar)(0xd800|(UChar)(entry>>10));
          if(offsets!=NULL__null) {
              *offsets++=sourceIndex;
          }
          byteIndex=0;
          c=(UChar)(0xdc00|(UChar)(entry&0x3ff));
          if(target<targetLimit) {
              *target++=c;
              if(offsets!=NULL__null) {
                  *offsets++=sourceIndex;
              }
          } else {
              /* target overflow */
              cnv->UCharErrorBuffer[0]=c;
              cnv->UCharErrorBufferLength=1;
              *pErrorCode=U_BUFFER_OVERFLOW_ERROR;

              offset=0;
              break;
          }
      } else if(action==MBCS_STATE_CHANGE_ONLY) {
          /*
           * This serves as a state change without any output.
           * It is useful for reading simple stateful encodings,
           * for example using just Shift-In/Shift-Out codes.
           * The 21 unused bits may later be used for more sophisticated
           * state transitions.
           */
          if(cnv->sharedData->mbcs.dbcsOnlyState==0) {
              byteIndex=0;
          } else {
              /* SI/SO are illegal for DBCS-only conversion */
              state=(uint8_t)(cnv->mode); /* restore the previous state */

              /* callback(illegal) */
              *pErrorCode=U_ILLEGAL_CHAR_FOUND;
          }
      } else if(action==MBCS_STATE_FALLBACK_DIRECT_16) {
          if(UCNV_TO_U_USE_FALLBACK(cnv)true) {
              /* output BMP code point */
              *target++=(UChar)MBCS_ENTRY_FINAL_VALUE_16(entry)(uint16_t)(entry);
              if(offsets!=NULL__null) {
                  *offsets++=sourceIndex;
              }
              byteIndex=0;
          }
      } else if(action==MBCS_STATE_UNASSIGNED) {
          /* just fall through */
      } else if(action==MBCS_STATE_ILLEGAL) {
          /* callback(illegal) */
          *pErrorCode=U_ILLEGAL_CHAR_FOUND;
      } else {
          /* reserved, must never occur */
          byteIndex=0;
      }

      /* end of action codes: prepare for a new character */
      offset=0;

      if(byteIndex==0) {
          sourceIndex=nextSourceIndex;
      } else if(U_FAILURE(*pErrorCode)) {
          /* callback(illegal) */
          if(byteIndex>1) {
              /*
               * Ticket 5691: consistent illegal sequences:
               * - We include at least the first byte in the illegal sequence.
               * - If any of the non-initial bytes could be the start of a character,
               *   we stop the illegal sequence before the first one of those.
               */
              UBool isDBCSOnly=(UBool)(cnv->sharedData->mbcs.dbcsOnlyState!=0);
              int8_t i;
              for(i=1;
                  i<byteIndex && !isSingleOrLead(stateTable, state, isDBCSOnly, bytes[i]);
                  ++i) {}
              if(i<byteIndex) {
                  /* Back out some bytes. */
                  int8_t backOutDistance=byteIndex-i;
                  int32_t bytesFromThisBuffer=(int32_t)(source-(const uint8_t *)pArgs->source);
                  byteIndex=i;  /* length of reported illegal byte sequence */
                  if(backOutDistance<=bytesFromThisBuffer) {
                      source-=backOutDistance;
                  } else {
                      /* Back out bytes from the previous buffer: Need to replay them. */
                      cnv->preToULength=(int8_t)(bytesFromThisBuffer-backOutDistance);
                      /* preToULength is negative! */
                      uprv_memcpy(cnv->preToU, bytes+i, -cnv->preToULength)do { clang diagnostic push
 clang diagnostic ignored "-Waddress"

 (void)0; (void)0; clang diagnostic pop
 :: memcpy(cnv->preToU
, bytes+i, -cnv->preToULength); } while (false);
                      source=(const uint8_t *)pArgs->source;
                  }
              }
          }
          break;
      } else /* unassigned sequences indicated with byteIndex>0 */ {
          /* try an extension mapping */
          pArgs->source=(const char *)source;
          byteIndex=_extToU(cnv, cnv->sharedData,
                            byteIndex, &source, sourceLimit,
                            &target, targetLimit,
                            &offsets, sourceIndex,
                            pArgs->flush,
                            pErrorCode);
          sourceIndex=nextSourceIndex+=(int32_t)(source-(const uint8_t *)pArgs->source);

          if(U_FAILURE(*pErrorCode)) {
              /* not mappable or buffer overflow */
              break;
          }
      }
  }

  /* set the converter state back into UConverter */
  cnv->toUnicodeStatus=offset;
  cnv->mode=state;
  cnv->toULength=byteIndex;

  /* write back the updated pointers */
  pArgs->source=(const char *)source;
  pArgs->target=target;
  pArgs->offsets=offsets;
2875}

2877/*
* This version of ucnv_MBCSGetNextUChar() is optimized for single-byte, single-state codepages.
* We still need a conversion loop in case we find reserved action codes, which are to be ignored.
*/
2881static UChar32
2882ucnv_MBCSSingleGetNextUChar(UConverterToUnicodeArgs *pArgs,
                      UErrorCode *pErrorCode) {
  UConverter *cnv;
  const int32_t (*stateTable)[256];
  const uint8_t *source, *sourceLimit;

  int32_t entry;
  uint8_t action;

  /* set up the local pointers */
  cnv=pArgs->converter;
  source=(const uint8_t *)pArgs->source;
  sourceLimit=(const uint8_t *)pArgs->sourceLimit;
  if((cnv->options&UCNV_OPTION_SWAP_LFNL0x10)!=0) {
      stateTable=(const int32_t (*)[256])cnv->sharedData->mbcs.swapLFNLStateTable;
  } else {
      stateTable=cnv->sharedData->mbcs.stateTable;
  }

  /* conversion loop */
  while(source<sourceLimit) {
      entry=stateTable[0][*source++];
      /* MBCS_ENTRY_IS_FINAL(entry) */

      /* write back the updated pointer early so that we can return directly */
      pArgs->source=(const char *)source;

      if(MBCS_ENTRY_FINAL_IS_VALID_DIRECT_16(entry)((entry)<(int32_t)0x80100000)) {
          /* output BMP code point */
          return (UChar)MBCS_ENTRY_FINAL_VALUE_16(entry)(uint16_t)(entry);
      }

      /*
       * An if-else-if chain provides more reliable performance for
       * the most common cases compared to a switch.
       */
      action=(uint8_t)(MBCS_ENTRY_FINAL_ACTION(entry)((((uint32_t)entry)>>20)&0xf));
      if( action==MBCS_STATE_VALID_DIRECT_20 ||
          (action==MBCS_STATE_FALLBACK_DIRECT_20 && UCNV_TO_U_USE_FALLBACK(cnv)true)
      ) {
          /* output supplementary code point */
          return (UChar32)(MBCS_ENTRY_FINAL_VALUE(entry)((entry)&0xfffff)+0x10000);
      } else if(action==MBCS_STATE_FALLBACK_DIRECT_16) {
          if(UCNV_TO_U_USE_FALLBACK(cnv)true) {
              /* output BMP code point */
              return (UChar)MBCS_ENTRY_FINAL_VALUE_16(entry)(uint16_t)(entry);
          }
      } else if(action==MBCS_STATE_UNASSIGNED) {
          /* just fall through */
      } else if(action==MBCS_STATE_ILLEGAL) {
          /* callback(illegal) */
          *pErrorCode=U_ILLEGAL_CHAR_FOUND;
      } else {
          /* reserved, must never occur */
          continue;
      }

      if(U_FAILURE(*pErrorCode)) {
          /* callback(illegal) */
          break;
      } else /* unassigned sequence */ {
          /* defer to the generic implementation */
          pArgs->source=(const char *)source-1;
          return UCNV_GET_NEXT_UCHAR_USE_TO_U-9;
      }
  }

  /* no output because of empty input or only state changes */
  *pErrorCode=U_INDEX_OUTOFBOUNDS_ERROR;
  return 0xffff;
2952}

2954/*
* Version of _MBCSToUnicodeWithOffsets() optimized for single-character
* conversion without offset handling.
*
* When a character does not have a mapping to Unicode, then we return to the
* generic ucnv_getNextUChar() code for extension/GB 18030 and error/callback
* handling.
* We also defer to the generic code in other complicated cases and have them
* ultimately handled by _MBCSToUnicodeWithOffsets() itself.
*
* All normal mappings and errors are handled here.
*/
2966static UChar32 U_CALLCONV
2967ucnv_MBCSGetNextUChar(UConverterToUnicodeArgs *pArgs,
                UErrorCode *pErrorCode) {
  UConverter *cnv;
  const uint8_t *source, *sourceLimit, *lastSource;

  const int32_t (*stateTable)[256];
  const uint16_t *unicodeCodeUnits;

  uint32_t offset;
  uint8_t state;

  int32_t entry;
  UChar32 c;
  uint8_t action;

  /* use optimized function if possible */
  cnv=pArgs->converter;

  if(cnv->preToULength>0) {
      /* use the generic code in ucnv_getNextUChar() to continue with a partial match */
      return UCNV_GET_NEXT_UCHAR_USE_TO_U-9;
  }

  if(cnv->sharedData->mbcs.unicodeMask&UCNV_HAS_SURROGATES2) {
      /*
       * Using the generic ucnv_getNextUChar() code lets us deal correctly
       * with the rare case of a codepage that maps single surrogates
       * without adding the complexity to this already complicated function here.
       */
      return UCNV_GET_NEXT_UCHAR_USE_TO_U-9;
  } else if(cnv->sharedData->mbcs.countStates==1) {
      return ucnv_MBCSSingleGetNextUChar(pArgs, pErrorCode);
  }

  /* set up the local pointers */
  source=lastSource=(const uint8_t *)pArgs->source;
  sourceLimit=(const uint8_t *)pArgs->sourceLimit;

  if((cnv->options&UCNV_OPTION_SWAP_LFNL0x10)!=0) {
      stateTable=(const int32_t (*)[256])cnv->sharedData->mbcs.swapLFNLStateTable;
  } else {
      stateTable=cnv->sharedData->mbcs.stateTable;
  }
  unicodeCodeUnits=cnv->sharedData->mbcs.unicodeCodeUnits;

  /* get the converter state from UConverter */
  offset=cnv->toUnicodeStatus;

  /*
   * if we are in the SBCS state for a DBCS-only converter,
   * then load the DBCS state from the MBCS data
   * (dbcsOnlyState==0 if it is not a DBCS-only converter)
   */
  if((state=(uint8_t)(cnv->mode))==0) {
      state=cnv->sharedData->mbcs.dbcsOnlyState;
  }

  /* conversion loop */
  c=U_SENTINEL(-1);
  while(source<sourceLimit) {
      entry=stateTable[state][*source++];
      if(MBCS_ENTRY_IS_TRANSITION(entry)((entry)>=0)) {
          state=(uint8_t)MBCS_ENTRY_TRANSITION_STATE(entry)(((uint32_t)entry)>>24);
          offset+=MBCS_ENTRY_TRANSITION_OFFSET(entry)((entry)&0xffffff);

          /* optimization for 1/2-byte input and BMP output */
          if( source<sourceLimit &&
              MBCS_ENTRY_IS_FINAL(entry=stateTable[state][*source])((entry=stateTable[state][*source])<0) &&
              MBCS_ENTRY_FINAL_ACTION(entry)((((uint32_t)entry)>>20)&0xf)==MBCS_STATE_VALID_16 &&
              (c=unicodeCodeUnits[offset+MBCS_ENTRY_FINAL_VALUE_16(entry)(uint16_t)(entry)])<0xfffe
          ) {
              ++source;
              state=(uint8_t)MBCS_ENTRY_FINAL_STATE(entry)((((uint32_t)entry)>>24)&0x7f); /* typically 0 */
              /* output BMP code point */
              break;
          }
      } else {
          /* save the previous state for proper extension mapping with SI/SO-stateful converters */
          cnv->mode=state;

          /* set the next state early so that we can reuse the entry variable */
          state=(uint8_t)MBCS_ENTRY_FINAL_STATE(entry)((((uint32_t)entry)>>24)&0x7f); /* typically 0 */

          /*
           * An if-else-if chain provides more reliable performance for
           * the most common cases compared to a switch.
           */
          action=(uint8_t)(MBCS_ENTRY_FINAL_ACTION(entry)((((uint32_t)entry)>>20)&0xf));
          if(action==MBCS_STATE_VALID_DIRECT_16) {
              /* output BMP code point */
              c=(UChar)MBCS_ENTRY_FINAL_VALUE_16(entry)(uint16_t)(entry);
              break;
          } else if(action==MBCS_STATE_VALID_16) {
              offset+=MBCS_ENTRY_FINAL_VALUE_16(entry)(uint16_t)(entry);
              c=unicodeCodeUnits[offset];
              if(c<0xfffe) {
                  /* output BMP code point */
                  break;
              } else if(c==0xfffe) {
                  if(UCNV_TO_U_USE_FALLBACK(cnv)true && (c=ucnv_MBCSGetFallback(&cnv->sharedData->mbcs, offset))!=0xfffe) {
                      break;
                  }
              } else {
                  /* callback(illegal) */
                  *pErrorCode=U_ILLEGAL_CHAR_FOUND;
              }
          } else if(action==MBCS_STATE_VALID_16_PAIR) {
              offset+=MBCS_ENTRY_FINAL_VALUE_16(entry)(uint16_t)(entry);
              c=unicodeCodeUnits[offset++];
              if(c<0xd800) {
                  /* output BMP code point below 0xd800 */
                  break;
              } else if(UCNV_TO_U_USE_FALLBACK(cnv)true ? c<=0xdfff : c<=0xdbff) {
                  /* output roundtrip or fallback supplementary code point */
                  c=((c&0x3ff)<<10)+unicodeCodeUnits[offset]+(0x10000-0xdc00);
                  break;
              } else if(UCNV_TO_U_USE_FALLBACK(cnv)true ? (c&0xfffe)==0xe000 : c==0xe000) {
                  /* output roundtrip BMP code point above 0xd800 or fallback BMP code point */
                  c=unicodeCodeUnits[offset];
                  break;
              } else if(c==0xffff) {
                  /* callback(illegal) */
                  *pErrorCode=U_ILLEGAL_CHAR_FOUND;
              }
          } else if(action==MBCS_STATE_VALID_DIRECT_20 ||
                    (action==MBCS_STATE_FALLBACK_DIRECT_20 && UCNV_TO_U_USE_FALLBACK(cnv)true)
          ) {
              /* output supplementary code point */
              c=(UChar32)(MBCS_ENTRY_FINAL_VALUE(entry)((entry)&0xfffff)+0x10000);
              break;
          } else if(action==MBCS_STATE_CHANGE_ONLY) {
              /*
               * This serves as a state change without any output.
               * It is useful for reading simple stateful encodings,
               * for example using just Shift-In/Shift-Out codes.
               * The 21 unused bits may later be used for more sophisticated
               * state transitions.
               */
              if(cnv->sharedData->mbcs.dbcsOnlyState!=0) {
                  /* SI/SO are illegal for DBCS-only conversion */
                  state=(uint8_t)(cnv->mode); /* restore the previous state */

                  /* callback(illegal) */
                  *pErrorCode=U_ILLEGAL_CHAR_FOUND;
              }
          } else if(action==MBCS_STATE_FALLBACK_DIRECT_16) {
              if(UCNV_TO_U_USE_FALLBACK(cnv)true) {
                  /* output BMP code point */
                  c=(UChar)MBCS_ENTRY_FINAL_VALUE_16(entry)(uint16_t)(entry);
                  break;
              }
          } else if(action==MBCS_STATE_UNASSIGNED) {
              /* just fall through */
          } else if(action==MBCS_STATE_ILLEGAL) {
              /* callback(illegal) */
              *pErrorCode=U_ILLEGAL_CHAR_FOUND;
          } else {
              /* reserved (must never occur), or only state change */
              offset=0;
              lastSource=source;
              continue;
          }

          /* end of action codes: prepare for a new character */
          offset=0;

          if(U_FAILURE(*pErrorCode)) {
              /* callback(illegal) */
              break;
          } else /* unassigned sequence */ {
              /* defer to the generic implementation */
              cnv->toUnicodeStatus=0;
              cnv->mode=state;
              pArgs->source=(const char *)lastSource;
              return UCNV_GET_NEXT_UCHAR_USE_TO_U-9;
          }
      }
  }

  if(c<0) {
      if(U_SUCCESS(*pErrorCode) && source==sourceLimit && lastSource<source) {
          /* incomplete character byte sequence */
          uint8_t *bytes=cnv->toUBytes;
          cnv->toULength=(int8_t)(source-lastSource);
          do {
              *bytes++=*lastSource++;
          } while(lastSource<source);
          *pErrorCode=U_TRUNCATED_CHAR_FOUND;
      } else if(U_FAILURE(*pErrorCode)) {
          /* callback(illegal) */
          /*
           * Ticket 5691: consistent illegal sequences:
           * - We include at least the first byte in the illegal sequence.
           * - If any of the non-initial bytes could be the start of a character,
           *   we stop the illegal sequence before the first one of those.
           */
          UBool isDBCSOnly=(UBool)(cnv->sharedData->mbcs.dbcsOnlyState!=0);
          uint8_t *bytes=cnv->toUBytes;
          *bytes++=*lastSource++;     /* first byte */
          if(lastSource==source) {
              cnv->toULength=1;
          } else /* lastSource<source: multi-byte character */ {
              int8_t i;
              for(i=1;
                  lastSource<source && !isSingleOrLead(stateTable, state, isDBCSOnly, *lastSource);
                  ++i
              ) {
                  *bytes++=*lastSource++;
              }
              cnv->toULength=i;
              source=lastSource;
          }
      } else {
          /* no output because of empty input or only state changes */
          *pErrorCode=U_INDEX_OUTOFBOUNDS_ERROR;
      }
      c=0xffff;
  }

  /* set the converter state back into UConverter, ready for a new character */
  cnv->toUnicodeStatus=0;
  cnv->mode=state;

  /* write back the updated pointer */
  pArgs->source=(const char *)source;
  return c;
3193}

3195#if 0
3196/*
* Code disabled 2002dec09 (ICU 2.4) because it is not currently used in ICU. markus
* Removal improves code coverage.
*/
3200/**
* This version of ucnv_MBCSSimpleGetNextUChar() is optimized for single-byte, single-state codepages.
* It does not handle the EBCDIC swaplfnl option (set in UConverter).
* It does not handle conversion extensions (_extToU()).
*/
3205U_CFUNCextern "C" UChar32
3206ucnv_MBCSSingleSimpleGetNextUChar(UConverterSharedData *sharedData,
                            uint8_t b, UBool useFallback) {
  int32_t entry;
  uint8_t action;

  entry=sharedData->mbcs.stateTable[0][b];
  /* MBCS_ENTRY_IS_FINAL(entry) */

  if(MBCS_ENTRY_FINAL_IS_VALID_DIRECT_16(entry)((entry)<(int32_t)0x80100000)) {
      /* output BMP code point */
      return (UChar)MBCS_ENTRY_FINAL_VALUE_16(entry)(uint16_t)(entry);
  }

  /*
   * An if-else-if chain provides more reliable performance for
   * the most common cases compared to a switch.
   */
  action=(uint8_t)(MBCS_ENTRY_FINAL_ACTION(entry)((((uint32_t)entry)>>20)&0xf));
  if(action==MBCS_STATE_VALID_DIRECT_20) {
      /* output supplementary code point */
      return 0x10000+MBCS_ENTRY_FINAL_VALUE(entry)((entry)&0xfffff);
  } else if(action==MBCS_STATE_FALLBACK_DIRECT_16) {
      if(!TO_U_USE_FALLBACK(useFallback)true) {
          return 0xfffe;
      }
      /* output BMP code point */
      return (UChar)MBCS_ENTRY_FINAL_VALUE_16(entry)(uint16_t)(entry);
  } else if(action==MBCS_STATE_FALLBACK_DIRECT_20) {
      if(!TO_U_USE_FALLBACK(useFallback)true) {
          return 0xfffe;
      }
      /* output supplementary code point */
      return 0x10000+MBCS_ENTRY_FINAL_VALUE(entry)((entry)&0xfffff);
  } else if(action==MBCS_STATE_UNASSIGNED) {
      return 0xfffe;
  } else if(action==MBCS_STATE_ILLEGAL) {
      return 0xffff;
  } else {
      /* reserved, must never occur */
      return 0xffff;
  }
3247}
3248#endif

3250/*
* This is a simple version of _MBCSGetNextUChar() that is used
* by other converter implementations.
* It only returns an "assigned" result if it consumes the entire input.
* It does not use state from the converter, nor error codes.
* It does not handle the EBCDIC swaplfnl option (set in UConverter).
* It handles conversion extensions but not GB 18030.
*
* Return value:
* U+fffe   unassigned
* U+ffff   illegal
* otherwise the Unicode code point
*/
3263U_CFUNCextern "C" UChar32
3264ucnv_MBCSSimpleGetNextUCharucnv_MBCSSimpleGetNextUChar_71(UConverterSharedData *sharedData,
                      const char *source, int32_t length,
                      UBool useFallback) {
  const int32_t (*stateTable)[256];
  const uint16_t *unicodeCodeUnits;

  uint32_t offset;
  uint8_t state, action;

  UChar32 c;
  int32_t i, entry;

  if(length<=0) {
      /* no input at all: "illegal" */
      return 0xffff;
  }

3281#if 0
3282/*
* Code disabled 2002dec09 (ICU 2.4) because it is not currently used in ICU. markus
* TODO In future releases, verify that this function is never called for SBCS
* conversions, i.e., that sharedData->mbcs.countStates==1 is still true.
* Removal improves code coverage.
*/
  /* use optimized function if possible */
  if(sharedData->mbcs.countStates==1) {
      if(length==1) {
          return ucnv_MBCSSingleSimpleGetNextUChar(sharedData, (uint8_t)*source, useFallback);
      } else {
          return 0xffff; /* illegal: more than a single byte for an SBCS converter */
      }
  }
3296#endif

  /* set up the local pointers */
  stateTable=sharedData->mbcs.stateTable;
  unicodeCodeUnits=sharedData->mbcs.unicodeCodeUnits;

  /* converter state */
  offset=0;
  state=sharedData->mbcs.dbcsOnlyState;

  /* conversion loop */
  for(i=0;;) {
      entry=stateTable[state][(uint8_t)source[i++]];
      if(MBCS_ENTRY_IS_TRANSITION(entry)((entry)>=0)) {
          state=(uint8_t)MBCS_ENTRY_TRANSITION_STATE(entry)(((uint32_t)entry)>>24);
          offset+=MBCS_ENTRY_TRANSITION_OFFSET(entry)((entry)&0xffffff);

          if(i==length) {
              return 0xffff; /* truncated character */
          }
      } else {
          /*
           * An if-else-if chain provides more reliable performance for
           * the most common cases compared to a switch.
           */
          action=(uint8_t)(MBCS_ENTRY_FINAL_ACTION(entry)((((uint32_t)entry)>>20)&0xf));
          if(action==MBCS_STATE_VALID_16) {
              offset+=MBCS_ENTRY_FINAL_VALUE_16(entry)(uint16_t)(entry);
              c=unicodeCodeUnits[offset];
              if(c!=0xfffe) {
                  /* done */
              } else if(UCNV_TO_U_USE_FALLBACK(cnv)true) {
                  c=ucnv_MBCSGetFallback(&sharedData->mbcs, offset);
              /* else done with 0xfffe */
              }
              break;
          } else if(action==MBCS_STATE_VALID_DIRECT_16) {
              /* output BMP code point */
              c=(UChar)MBCS_ENTRY_FINAL_VALUE_16(entry)(uint16_t)(entry);
              break;
          } else if(action==MBCS_STATE_VALID_16_PAIR) {
              offset+=MBCS_ENTRY_FINAL_VALUE_16(entry)(uint16_t)(entry);
              c=unicodeCodeUnits[offset++];
              if(c<0xd800) {
                  /* output BMP code point below 0xd800 */
              } else if(UCNV_TO_U_USE_FALLBACK(cnv)true ? c<=0xdfff : c<=0xdbff) {
                  /* output roundtrip or fallback supplementary code point */
                  c=(UChar32)(((c&0x3ff)<<10)+unicodeCodeUnits[offset]+(0x10000-0xdc00));
              } else if(UCNV_TO_U_USE_FALLBACK(cnv)true ? (c&0xfffe)==0xe000 : c==0xe000) {
                  /* output roundtrip BMP code point above 0xd800 or fallback BMP code point */
                  c=unicodeCodeUnits[offset];
              } else if(c==0xffff) {
                  return 0xffff;
              } else {
                  c=0xfffe;
              }
              break;
          } else if(action==MBCS_STATE_VALID_DIRECT_20) {
              /* output supplementary code point */
              c=0x10000+MBCS_ENTRY_FINAL_VALUE(entry)((entry)&0xfffff);
              break;
          } else if(action==MBCS_STATE_FALLBACK_DIRECT_16) {
              if(!TO_U_USE_FALLBACK(useFallback)true) {
                  c=0xfffe;
                  break;
              }
              /* output BMP code point */
              c=(UChar)MBCS_ENTRY_FINAL_VALUE_16(entry)(uint16_t)(entry);
              break;
          } else if(action==MBCS_STATE_FALLBACK_DIRECT_20) {
              if(!TO_U_USE_FALLBACK(useFallback)true) {
                  c=0xfffe;
                  break;
              }
              /* output supplementary code point */
              c=0x10000+MBCS_ENTRY_FINAL_VALUE(entry)((entry)&0xfffff);
              break;
          } else if(action==MBCS_STATE_UNASSIGNED) {
              c=0xfffe;
              break;
          }

          /*
           * forbid MBCS_STATE_CHANGE_ONLY for this function,
           * and MBCS_STATE_ILLEGAL and reserved action codes
           */
          return 0xffff;
      }
  }

  if(i!=length) {
      /* illegal for this function: not all input consumed */
      return 0xffff;
  }

  if(c==0xfffe) {
      /* try an extension mapping */
      const int32_t *cx=sharedData->mbcs.extIndexes;
      if(cx!=NULL__null) {
          return ucnv_extSimpleMatchToUucnv_extSimpleMatchToU_71(cx, source, length, useFallback);
      }
  }

  return c;
3400}

3402/* MBCS-from-Unicode conversion functions ----------------------------------- */

3404/* This version of ucnv_MBCSFromUnicodeWithOffsets() is optimized for double-byte codepages. */
3405static void
3406ucnv_MBCSDoubleFromUnicodeWithOffsets(UConverterFromUnicodeArgs *pArgs,
                                UErrorCode *pErrorCode) {
  UConverter *cnv;
  const UChar *source, *sourceLimit;
  uint8_t *target;
  int32_t targetCapacity;
  int32_t *offsets;

  const uint16_t *table;
  const uint16_t *mbcsIndex;
  const uint8_t *bytes;

  UChar32 c;

  int32_t sourceIndex, nextSourceIndex;

  uint32_t stage2Entry;
  uint32_t asciiRoundtrips;
  uint32_t value;
  uint8_t unicodeMask;

  /* use optimized function if possible */
  cnv=pArgs->converter;
  unicodeMask=cnv->sharedData->mbcs.unicodeMask;

  /* set up the local pointers */
  source=pArgs->source;
  sourceLimit=pArgs->sourceLimit;
  target=(uint8_t *)pArgs->target;
  targetCapacity=(int32_t)(pArgs->targetLimit-pArgs->target);
  offsets=pArgs->offsets;

  table=cnv->sharedData->mbcs.fromUnicodeTable;
  mbcsIndex=cnv->sharedData->mbcs.mbcsIndex;
  if((cnv->options&UCNV_OPTION_SWAP_LFNL0x10)!=0) {
      bytes=cnv->sharedData->mbcs.swapLFNLFromUnicodeBytes;
  } else {
      bytes=cnv->sharedData->mbcs.fromUnicodeBytes;
  }
  asciiRoundtrips=cnv->sharedData->mbcs.asciiRoundtrips;

  /* get the converter state from UConverter */
  c=cnv->fromUChar32;

  /* sourceIndex=-1 if the current character began in the previous buffer */
  sourceIndex= c==0 ? 0 : -1;
  nextSourceIndex=0;

  /* conversion loop */
  if(c!=0 && targetCapacity>0) {
      goto getTrail;
  }

  while(source<sourceLimit) {
      /*
       * This following test is to see if available input would overflow the output.
       * It does not catch output of more than one byte that
       * overflows as a result of a multi-byte character or callback output
       * from the last source character.
       * Therefore, those situations also test for overflows and will
       * then break the loop, too.
       */
      if(targetCapacity>0) {
          /*
           * Get a correct Unicode code point:
           * a single UChar for a BMP code point or
           * a matched surrogate pair for a "supplementary code point".
           */
          c=*source++;
          ++nextSourceIndex;
          if(c<=0x7f && IS_ASCII_ROUNDTRIP(c, asciiRoundtrips)(((asciiRoundtrips) & (1<<((c)>>2)))!=0)) {
              *target++=(uint8_t)c;
              if(offsets!=NULL__null) {
                  *offsets++=sourceIndex;
                  sourceIndex=nextSourceIndex;
              }
              --targetCapacity;
              c=0;
              continue;
          }
          /*
           * utf8Friendly table: Test for <=0xd7ff rather than <=MBCS_FAST_MAX
           * to avoid dealing with surrogates.
           * MBCS_FAST_MAX must be >=0xd7ff.
           */
          if(c<=0xd7ff) {
              value=DBCS_RESULT_FROM_MOST_BMP(mbcsIndex, (const uint16_t *)bytes, c)((const uint16_t *)bytes)[ (mbcsIndex)[(c)>>6] +((c)&
0x3f) ];
              /* There are only roundtrips (!=0) and no-mapping (==0) entries. */
              if(value==0) {
                  goto unassigned;
              }
              /* output the value */
          } else {
              /*
               * This also tests if the codepage maps single surrogates.
               * If it does, then surrogates are not paired but mapped separately.
               * Note that in this case unmatched surrogates are not detected.
               */
              if(U16_IS_SURROGATE(c)(((c)&0xfffff800)==0xd800) && !(unicodeMask&UCNV_HAS_SURROGATES2)) {
                  if(U16_IS_SURROGATE_LEAD(c)(((c)&0x400)==0)) {
3506getTrail:
                      if(source<sourceLimit) {
                          /* test the following code unit */
                          UChar trail=*source;
                          if(U16_IS_TRAIL(trail)(((trail)&0xfffffc00)==0xdc00)) {
                              ++source;
                              ++nextSourceIndex;
                              c=U16_GET_SUPPLEMENTARY(c, trail)(((UChar32)(c)<<10UL)+(UChar32)(trail)-((0xd800<<
10UL)+0xdc00-0x10000));
                              if(!(unicodeMask&UCNV_HAS_SUPPLEMENTARY1)) {
                                  /* BMP-only codepages are stored without stage 1 entries for supplementary code points */
                                  /* callback(unassigned) */
                                  goto unassigned;
                              }
                              /* convert this supplementary code point */
                              /* exit this condition tree */
                          } else {
                              /* this is an unmatched lead code unit (1st surrogate) */
                              /* callback(illegal) */
                              *pErrorCode=U_ILLEGAL_CHAR_FOUND;
                              break;
                          }
                      } else {
                          /* no more input */
                          break;
                      }
                  } else {
                      /* this is an unmatched trail code unit (2nd surrogate) */
                      /* callback(illegal) */
                      *pErrorCode=U_ILLEGAL_CHAR_FOUND;
                      break;
                  }
              }

              /* convert the Unicode code point in c into codepage bytes */
              stage2Entry=MBCS_STAGE_2_FROM_U(table, c)((const uint32_t *)(table))[ (table)[(c)>>10] +(((c)>>
4)&0x3f) ];

              /* get the bytes and the length for the output */
              /* MBCS_OUTPUT_2 */
              value=MBCS_VALUE_2_FROM_STAGE_2(bytes, stage2Entry, c)((uint16_t *)(bytes))[16*(uint32_t)(uint16_t)(stage2Entry)+((
c)&0xf)];

              /* is this code point assigned, or do we use fallbacks? */
              if(!(MBCS_FROM_U_IS_ROUNDTRIP(stage2Entry, c)( ((stage2Entry) & ((uint32_t)1<< (16+((c)&0xf)
) )) !=0) ||
                   (UCNV_FROM_U_USE_FALLBACK(cnv, c)(((cnv)->useFallback) || ((uint32_t)((c)-0xe000)<0x1900
 || (uint32_t)((c)-0xf0000)<0x20000)) && value!=0))
              ) {
                  /*
                   * We allow a 0 byte output if the "assigned" bit is set for this entry.
                   * There is no way with this data structure for fallback output
                   * to be a zero byte.
                   */

3556unassigned:
                  /* try an extension mapping */
                  pArgs->source=source;
                  c=_extFromU(cnv, cnv->sharedData,
                              c, &source, sourceLimit,
                              &target, target+targetCapacity,
                              &offsets, sourceIndex,
                              pArgs->flush,
                              pErrorCode);
                  nextSourceIndex+=(int32_t)(source-pArgs->source);

                  if(U_FAILURE(*pErrorCode)) {
                      /* not mappable or buffer overflow */
                      break;
                  } else {
                      /* a mapping was written to the target, continue */

                      /* recalculate the targetCapacity after an extension mapping */
                      targetCapacity=(int32_t)(pArgs->targetLimit-(char *)target);

                      /* normal end of conversion: prepare for a new character */
                      sourceIndex=nextSourceIndex;
                      continue;
                  }
              }
          }

          /* write the output character bytes from value and length */
          /* from the first if in the loop we know that targetCapacity>0 */
          if(value<=0xff) {
              /* this is easy because we know that there is enough space */
              *target++=(uint8_t)value;
              if(offsets!=NULL__null) {
                  *offsets++=sourceIndex;
              }
              --targetCapacity;
          } else /* length==2 */ {
              *target++=(uint8_t)(value>>8);
              if(2<=targetCapacity) {
                  *target++=(uint8_t)value;
                  if(offsets!=NULL__null) {
                      *offsets++=sourceIndex;
                      *offsets++=sourceIndex;
                  }
                  targetCapacity-=2;
              } else {
                  if(offsets!=NULL__null) {
                      *offsets++=sourceIndex;
                  }
                  cnv->charErrorBuffer[0]=(char)value;
                  cnv->charErrorBufferLength=1;

                  /* target overflow */
                  targetCapacity=0;
                  *pErrorCode=U_BUFFER_OVERFLOW_ERROR;
                  c=0;
                  break;
              }
          }

          /* normal end of conversion: prepare for a new character */
          c=0;
          sourceIndex=nextSourceIndex;
          continue;
      } else {
          /* target is full */
          *pErrorCode=U_BUFFER_OVERFLOW_ERROR;
          break;
      }
  }

  /* set the converter state back into UConverter */
  cnv->fromUChar32=c;

  /* write back the updated pointers */
  pArgs->source=source;
  pArgs->target=(char *)target;
  pArgs->offsets=offsets;
3634}

3636/* This version of ucnv_MBCSFromUnicodeWithOffsets() is optimized for single-byte codepages. */
3637static void
3638ucnv_MBCSSingleFromUnicodeWithOffsets(UConverterFromUnicodeArgs *pArgs,
                                UErrorCode *pErrorCode) {
  UConverter *cnv;
  const UChar *source, *sourceLimit;
  uint8_t *target;
  int32_t targetCapacity;
  int32_t *offsets;

  const uint16_t *table;
  const uint16_t *results;

  UChar32 c;

  int32_t sourceIndex, nextSourceIndex;

  uint16_t value, minValue;
  UBool hasSupplementary;

  /* set up the local pointers */
  cnv=pArgs->converter;
  source=pArgs->source;
  sourceLimit=pArgs->sourceLimit;
  target=(uint8_t *)pArgs->target;
  targetCapacity=(int32_t)(pArgs->targetLimit-pArgs->target);
  offsets=pArgs->offsets;

  table=cnv->sharedData->mbcs.fromUnicodeTable;
  if((cnv->options&UCNV_OPTION_SWAP_LFNL0x10)!=0) {
      results=(uint16_t *)cnv->sharedData->mbcs.swapLFNLFromUnicodeBytes;
  } else {
      results=(uint16_t *)cnv->sharedData->mbcs.fromUnicodeBytes;
  }

  if(cnv->useFallback) {
      /* use all roundtrip and fallback results */
      minValue=0x800;
  } else {
      /* use only roundtrips and fallbacks from private-use characters */
      minValue=0xc00;
  }
  hasSupplementary=(UBool)(cnv->sharedData->mbcs.unicodeMask&UCNV_HAS_SUPPLEMENTARY1);

  /* get the converter state from UConverter */
  c=cnv->fromUChar32;

  /* sourceIndex=-1 if the current character began in the previous buffer */
  sourceIndex= c==0 ? 0 : -1;
  nextSourceIndex=0;

  /* conversion loop */
  if(c!=0 && targetCapacity>0) {
      goto getTrail;
  }

  while(source<sourceLimit) {
      /*
       * This following test is to see if available input would overflow the output.
       * It does not catch output of more than one byte that
       * overflows as a result of a multi-byte character or callback output
       * from the last source character.
       * Therefore, those situations also test for overflows and will
       * then break the loop, too.
       */
      if(targetCapacity>0) {
          /*
           * Get a correct Unicode code point:
           * a single UChar for a BMP code point or
           * a matched surrogate pair for a "supplementary code point".
           */
          c=*source++;
          ++nextSourceIndex;
          if(U16_IS_SURROGATE(c)(((c)&0xfffff800)==0xd800)) {
              if(U16_IS_SURROGATE_LEAD(c)(((c)&0x400)==0)) {
3711getTrail:
                  if(source<sourceLimit) {
                      /* test the following code unit */
                      UChar trail=*source;
                      if(U16_IS_TRAIL(trail)(((trail)&0xfffffc00)==0xdc00)) {
                          ++source;
                          ++nextSourceIndex;
                          c=U16_GET_SUPPLEMENTARY(c, trail)(((UChar32)(c)<<10UL)+(UChar32)(trail)-((0xd800<<
10UL)+0xdc00-0x10000));
                          if(!hasSupplementary) {
                              /* BMP-only codepages are stored without stage 1 entries for supplementary code points */
                              /* callback(unassigned) */
                              goto unassigned;
                          }
                          /* convert this supplementary code point */
                          /* exit this condition tree */
                      } else {
                          /* this is an unmatched lead code unit (1st surrogate) */
                          /* callback(illegal) */
                          *pErrorCode=U_ILLEGAL_CHAR_FOUND;
                          break;
                      }
                  } else {
                      /* no more input */
                      break;
                  }
              } else {
                  /* this is an unmatched trail code unit (2nd surrogate) */
                  /* callback(illegal) */
                  *pErrorCode=U_ILLEGAL_CHAR_FOUND;
                  break;
              }
          }

          /* convert the Unicode code point in c into codepage bytes */
          value=MBCS_SINGLE_RESULT_FROM_U(table, results, c)(results)[ (table)[ (table)[(c)>>10] +(((c)>>4)&
0x3f) ] +((c)&0xf) ];

          /* is this code point assigned, or do we use fallbacks? */
          if(value>=minValue) {
              /* assigned, write the output character bytes from value and length */
              /* length==1 */
              /* this is easy because we know that there is enough space */
              *target++=(uint8_t)value;
              if(offsets!=NULL__null) {
                  *offsets++=sourceIndex;
              }
              --targetCapacity;

              /* normal end of conversion: prepare for a new character */
              c=0;
              sourceIndex=nextSourceIndex;
          } else { /* unassigned */
3762unassigned:
              /* try an extension mapping */
              pArgs->source=source;
              c=_extFromU(cnv, cnv->sharedData,
                          c, &source, sourceLimit,
                          &target, target+targetCapacity,
                          &offsets, sourceIndex,
                          pArgs->flush,
                          pErrorCode);
              nextSourceIndex+=(int32_t)(source-pArgs->source);

              if(U_FAILURE(*pErrorCode)) {
                  /* not mappable or buffer overflow */
                  break;
              } else {
                  /* a mapping was written to the target, continue */

                  /* recalculate the targetCapacity after an extension mapping */
                  targetCapacity=(int32_t)(pArgs->targetLimit-(char *)target);

                  /* normal end of conversion: prepare for a new character */
                  sourceIndex=nextSourceIndex;
              }
          }
      } else {
          /* target is full */
          *pErrorCode=U_BUFFER_OVERFLOW_ERROR;
          break;
      }
  }

  /* set the converter state back into UConverter */
  cnv->fromUChar32=c;

  /* write back the updated pointers */
  pArgs->source=source;
  pArgs->target=(char *)target;
  pArgs->offsets=offsets;
3800}

3802/*
* This version of ucnv_MBCSFromUnicode() is optimized for single-byte codepages
* that map only to and from the BMP.
* In addition to single-byte/state optimizations, the offset calculations
* become much easier.
* It would be possible to use the sbcsIndex for UTF-8-friendly tables,
* but measurements have shown that this diminishes performance
* in more cases than it improves it.
* See SVN revision 21013 (2007-feb-06) for the last version with #if switches
* for various MBCS and SBCS optimizations.
*/
3813static void
3814ucnv_MBCSSingleFromBMPWithOffsets(UConverterFromUnicodeArgs *pArgs,
                            UErrorCode *pErrorCode) {
  UConverter *cnv;
  const UChar *source, *sourceLimit, *lastSource;
  uint8_t *target;
  int32_t targetCapacity, length;
  int32_t *offsets;

  const uint16_t *table;
  const uint16_t *results;

  UChar32 c;

  int32_t sourceIndex;

  uint32_t asciiRoundtrips;
  uint16_t value, minValue;

  /* set up the local pointers */
  cnv=pArgs->converter;
  source=pArgs->source;
  sourceLimit=pArgs->sourceLimit;
  target=(uint8_t *)pArgs->target;
  targetCapacity=(int32_t)(pArgs->targetLimit-pArgs->target);
  offsets=pArgs->offsets;

  table=cnv->sharedData->mbcs.fromUnicodeTable;
  if((cnv->options&UCNV_OPTION_SWAP_LFNL0x10)!=0) {
      results=(uint16_t *)cnv->sharedData->mbcs.swapLFNLFromUnicodeBytes;
  } else {
      results=(uint16_t *)cnv->sharedData->mbcs.fromUnicodeBytes;
  }
  asciiRoundtrips=cnv->sharedData->mbcs.asciiRoundtrips;

  if(cnv->useFallback) {
      /* use all roundtrip and fallback results */
      minValue=0x800;
  } else {
      /* use only roundtrips and fallbacks from private-use characters */
      minValue=0xc00;
  }

  /* get the converter state from UConverter */
  c=cnv->fromUChar32;

  /* sourceIndex=-1 if the current character began in the previous buffer */
  sourceIndex= c==0 ? 0 : -1;
  lastSource=source;

  /*
   * since the conversion here is 1:1 UChar:uint8_t, we need only one counter
   * for the minimum of the sourceLength and targetCapacity
   */
  length=(int32_t)(sourceLimit-source);
  if(length<targetCapacity) {
      targetCapacity=length;
  }

  /* conversion loop */
  if(c!=0 && targetCapacity>0) {
      goto getTrail;
  }

3877#if MBCS_UNROLL_SINGLE_FROM_BMP0
  /* unrolling makes it slower on Pentium III/Windows 2000?! */
  /* unroll the loop with the most common case */
3880unrolled:
  if(targetCapacity>=4) {
      int32_t count, loops;
      uint16_t andedValues;

      loops=count=targetCapacity>>2;
      do {
          c=*source++;
          andedValues=value=MBCS_SINGLE_RESULT_FROM_U(table, results, c)(results)[ (table)[ (table)[(c)>>10] +(((c)>>4)&
0x3f) ] +((c)&0xf) ];
          *target++=(uint8_t)value;
          c=*source++;
          andedValues&=value=MBCS_SINGLE_RESULT_FROM_U(table, results, c)(results)[ (table)[ (table)[(c)>>10] +(((c)>>4)&
0x3f) ] +((c)&0xf) ];
          *target++=(uint8_t)value;
          c=*source++;
          andedValues&=value=MBCS_SINGLE_RESULT_FROM_U(table, results, c)(results)[ (table)[ (table)[(c)>>10] +(((c)>>4)&
0x3f) ] +((c)&0xf) ];
          *target++=(uint8_t)value;
          c=*source++;
          andedValues&=value=MBCS_SINGLE_RESULT_FROM_U(table, results, c)(results)[ (table)[ (table)[(c)>>10] +(((c)>>4)&
0x3f) ] +((c)&0xf) ];
          *target++=(uint8_t)value;

          /* were all 4 entries really valid? */
          if(andedValues<minValue) {
              /* no, return to the first of these 4 */
              source-=4;
              target-=4;
              break;
          }
      } while(--count>0);
      count=loops-count;
      targetCapacity-=4*count;

      if(offsets!=NULL__null) {
          lastSource+=4*count;
          while(count>0) {
              *offsets++=sourceIndex++;
              *offsets++=sourceIndex++;
              *offsets++=sourceIndex++;
              *offsets++=sourceIndex++;
              --count;
          }
      }

      c=0;
  }
3924#endif

  while(targetCapacity>0) {
      /*
       * Get a correct Unicode code point:
       * a single UChar for a BMP code point or
       * a matched surrogate pair for a "supplementary code point".
       */
      c=*source++;
      /*
       * Do not immediately check for single surrogates:
       * Assume that they are unassigned and check for them in that case.
       * This speeds up the conversion of assigned characters.
       */
      /* convert the Unicode code point in c into codepage bytes */
      if(c<=0x7f && IS_ASCII_ROUNDTRIP(c, asciiRoundtrips)(((asciiRoundtrips) & (1<<((c)>>2)))!=0)) {
          *target++=(uint8_t)c;
          --targetCapacity;
          c=0;
          continue;
      }
      value=MBCS_SINGLE_RESULT_FROM_U(table, results, c)(results)[ (table)[ (table)[(c)>>10] +(((c)>>4)&
0x3f) ] +((c)&0xf) ];
      /* is this code point assigned, or do we use fallbacks? */
      if(value>=minValue) {
          /* assigned, write the output character bytes from value and length */
          /* length==1 */
          /* this is easy because we know that there is enough space */
          *target++=(uint8_t)value;
          --targetCapacity;

          /* normal end of conversion: prepare for a new character */
          c=0;
          continue;
      } else if(!U16_IS_SURROGATE(c)(((c)&0xfffff800)==0xd800)) {
          /* normal, unassigned BMP character */
      } else if(U16_IS_SURROGATE_LEAD(c)(((c)&0x400)==0)) {
3960getTrail:
          if(source<sourceLimit) {
              /* test the following code unit */
              UChar trail=*source;
              if(U16_IS_TRAIL(trail)(((trail)&0xfffffc00)==0xdc00)) {
                  ++source;
                  c=U16_GET_SUPPLEMENTARY(c, trail)(((UChar32)(c)<<10UL)+(UChar32)(trail)-((0xd800<<
10UL)+0xdc00-0x10000));
                  /* this codepage does not map supplementary code points */
                  /* callback(unassigned) */
              } else {
                  /* this is an unmatched lead code unit (1st surrogate) */
                  /* callback(illegal) */
                  *pErrorCode=U_ILLEGAL_CHAR_FOUND;
                  break;
              }
          } else {
              /* no more input */
              if (pArgs->flush) {
                  *pErrorCode=U_TRUNCATED_CHAR_FOUND;
              }
              break;
          }
      } else {
          /* this is an unmatched trail code unit (2nd surrogate) */
          /* callback(illegal) */
          *pErrorCode=U_ILLEGAL_CHAR_FOUND;
          break;
      }

      /* c does not have a mapping */

      /* get the number of code units for c to correctly advance sourceIndex */
      length=U16_LENGTH(c)((uint32_t)(c)<=0xffff ? 1 : 2);

      /* set offsets since the start or the last extension */
      if(offsets!=NULL__null) {
          int32_t count=(int32_t)(source-lastSource);

          /* do not set the offset for this character */
          count-=length;

          while(count>0) {
              *offsets++=sourceIndex++;
              --count;
          }
          /* offsets and sourceIndex are now set for the current character */
      }

      /* try an extension mapping */
      lastSource=source;
      c=_extFromU(cnv, cnv->sharedData,
                  c, &source, sourceLimit,
                  &target, (const uint8_t *)(pArgs->targetLimit),
                  &offsets, sourceIndex,
                  pArgs->flush,
                  pErrorCode);
      sourceIndex+=length+(int32_t)(source-lastSource);
      lastSource=source;

      if(U_FAILURE(*pErrorCode)) {
          /* not mappable or buffer overflow */
          break;
      } else {
          /* a mapping was written to the target, continue */

          /* recalculate the targetCapacity after an extension mapping */
          targetCapacity=(int32_t)(pArgs->targetLimit-(char *)target);
          length=(int32_t)(sourceLimit-source);
          if(length<targetCapacity) {
              targetCapacity=length;
          }
      }

4033#if MBCS_UNROLL_SINGLE_FROM_BMP0
      /* unrolling makes it slower on Pentium III/Windows 2000?! */
      goto unrolled;
4036#endif
  }

  if(U_SUCCESS(*pErrorCode) && source<sourceLimit && target>=(uint8_t *)pArgs->targetLimit) {
      /* target is full */
      *pErrorCode=U_BUFFER_OVERFLOW_ERROR;
  }

  /* set offsets since the start or the last callback */
  if(offsets!=NULL__null) {
      size_t count=source-lastSource;
      if (count > 0 && *pErrorCode == U_TRUNCATED_CHAR_FOUND) {
          /*
          Caller gave us a partial supplementary character,
          which this function couldn't convert in any case.
          The callback will handle the offset.
          */
          count--;
      }
      while(count>0) {
          *offsets++=sourceIndex++;
          --count;
      }
  }

  /* set the converter state back into UConverter */
  cnv->fromUChar32=c;

  /* write back the updated pointers */
  pArgs->source=source;
  pArgs->target=(char *)target;
  pArgs->offsets=offsets;
4068}

4070U_CFUNCextern "C" void
4071ucnv_MBCSFromUnicodeWithOffsetsucnv_MBCSFromUnicodeWithOffsets_71(UConverterFromUnicodeArgs *pArgs,
                          UErrorCode *pErrorCode) {
  UConverter *cnv;
  const UChar *source, *sourceLimit;
  uint8_t *target;
  int32_t targetCapacity;
  int32_t *offsets;

  const uint16_t *table;
  const uint16_t *mbcsIndex;
  const uint8_t *p, *bytes;
  uint8_t outputType;

  UChar32 c;

  int32_t prevSourceIndex, sourceIndex, nextSourceIndex;

  uint32_t stage2Entry;
  uint32_t asciiRoundtrips;
  uint32_t value;
  /* Shift-In and Shift-Out byte sequences differ by encoding scheme. */
  uint8_t siBytes[2] = {0, 0};
  uint8_t soBytes[2] = {0, 0};
  uint8_t siLength, soLength;
  int32_t length = 0, prevLength;
  uint8_t unicodeMask;

  cnv=pArgs->converter;

  if(cnv->preFromUFirstCP>=0) {
      /*
       * pass sourceIndex=-1 because we continue from an earlier buffer
       * in the future, this may change with continuous offsets
       */
      ucnv_extContinueMatchFromUucnv_extContinueMatchFromU_71(cnv, pArgs, -1, pErrorCode);

      if(U_FAILURE(*pErrorCode) || cnv->preFromULength<0) {
          return;
      }
  }

  /* use optimized function if possible */
  outputType=cnv->sharedData->mbcs.outputType;
  unicodeMask=cnv->sharedData->mbcs.unicodeMask;
  if(outputType==MBCS_OUTPUT_1 && !(unicodeMask&UCNV_HAS_SURROGATES2)) {
      if(!(unicodeMask&UCNV_HAS_SUPPLEMENTARY1)) {
          ucnv_MBCSSingleFromBMPWithOffsets(pArgs, pErrorCode);
      } else {
          ucnv_MBCSSingleFromUnicodeWithOffsets(pArgs, pErrorCode);
      }
      return;
  } else if(outputType==MBCS_OUTPUT_2 && cnv->sharedData->mbcs.utf8Friendly) {
      ucnv_MBCSDoubleFromUnicodeWithOffsets(pArgs, pErrorCode);
      return;
  }

  /* set up the local pointers */
  source=pArgs->source;
  sourceLimit=pArgs->sourceLimit;
  target=(uint8_t *)pArgs->target;
  targetCapacity=(int32_t)(pArgs->targetLimit-pArgs->target);
  offsets=pArgs->offsets;

  table=cnv->sharedData->mbcs.fromUnicodeTable;
  if(cnv->sharedData->mbcs.utf8Friendly) {
      mbcsIndex=cnv->sharedData->mbcs.mbcsIndex;
  } else {
      mbcsIndex=NULL__null;
  }
  if((cnv->options&UCNV_OPTION_SWAP_LFNL0x10)!=0) {
      bytes=cnv->sharedData->mbcs.swapLFNLFromUnicodeBytes;
  } else {
      bytes=cnv->sharedData->mbcs.fromUnicodeBytes;
  }
  asciiRoundtrips=cnv->sharedData->mbcs.asciiRoundtrips;

  /* get the converter state from UConverter */
  c=cnv->fromUChar32;

  if(outputType==MBCS_OUTPUT_2_SISO) {
      prevLength=cnv->fromUnicodeStatus;
      if(prevLength==0) {
          /* set the real value */
          prevLength=1;
      }
  } else {
      /* prevent fromUnicodeStatus from being set to something non-0 */
      prevLength=0;
  }

  /* sourceIndex=-1 if the current character began in the previous buffer */
  prevSourceIndex=-1;
  sourceIndex= c==0 ? 0 : -1;
  nextSourceIndex=0;

  /* Get the SI/SO character for the converter */
  siLength = static_cast<uint8_t>(getSISOBytes(SI, cnv->options, siBytes));
  soLength = static_cast<uint8_t>(getSISOBytes(SO, cnv->options, soBytes));

  /* conversion loop */
  /*
   * This is another piece of ugly code:
   * A goto into the loop if the converter state contains a first surrogate
   * from the previous function call.
   * It saves me to check in each loop iteration a check of if(c==0)
   * and duplicating the trail-surrogate-handling code in the else
   * branch of that check.
   * I could not find any other way to get around this other than
   * using a function call for the conversion and callback, which would
   * be even more inefficient.
   *
   * Markus Scherer 2000-jul-19
   */
  if(c!=0 && targetCapacity>0) {
      goto getTrail;
  }

  while(source<sourceLimit) {
      /*
       * This following test is to see if available input would overflow the output.
       * It does not catch output of more than one byte that
       * overflows as a result of a multi-byte character or callback output
       * from the last source character.
       * Therefore, those situations also test for overflows and will
       * then break the loop, too.
       */
      if(targetCapacity>0) {
          /*
           * Get a correct Unicode code point:
           * a single UChar for a BMP code point or
           * a matched surrogate pair for a "supplementary code point".
           */
          c=*source++;
          ++nextSourceIndex;
          if(c<=0x7f && IS_ASCII_ROUNDTRIP(c, asciiRoundtrips)(((asciiRoundtrips) & (1<<((c)>>2)))!=0)) {
              *target++=(uint8_t)c;
              if(offsets!=NULL__null) {
                  *offsets++=sourceIndex;
                  prevSourceIndex=sourceIndex;
                  sourceIndex=nextSourceIndex;
              }
              --targetCapacity;
              c=0;
              continue;
          }
          /*
           * utf8Friendly table: Test for <=0xd7ff rather than <=MBCS_FAST_MAX
           * to avoid dealing with surrogates.
           * MBCS_FAST_MAX must be >=0xd7ff.
           */
          if(c<=0xd7ff && mbcsIndex!=NULL__null) {
              value=mbcsIndex[c>>6];

              /* get the bytes and the length for the output (copied from below and adapted for utf8Friendly data) */
              /* There are only roundtrips (!=0) and no-mapping (==0) entries. */
              switch(outputType) {
              case MBCS_OUTPUT_2:
                  value=((const uint16_t *)bytes)[value +(c&0x3f)];
                  if(value<=0xff) {
                      if(value==0) {
                          goto unassigned;
                      } else {
                          length=1;
                      }
                  } else {
                      length=2;
                  }
                  break;
              case MBCS_OUTPUT_2_SISO:
                  /* 1/2-byte stateful with Shift-In/Shift-Out */
                  /*
                   * Save the old state in the converter object
                   * right here, then change the local prevLength state variable if necessary.
                   * Then, if this character turns out to be unassigned or a fallback that
                   * is not taken, the callback code must not save the new state in the converter
                   * because the new state is for a character that is not output.
                   * However, the callback must still restore the state from the converter
                   * in case the callback function changed it for its output.
                   */
                  cnv->fromUnicodeStatus=prevLength; /* save the old state */
                  value=((const uint16_t *)bytes)[value +(c&0x3f)];
                  if(value<=0xff) {
                      if(value==0) {
                          goto unassigned;
                      } else if(prevLength<=1) {
                          length=1;
                      } else {
                          /* change from double-byte mode to single-byte */
                          if (siLength == 1) {
                              value|=(uint32_t)siBytes[0]<<8;
                              length = 2;
                          } else if (siLength == 2) {
                              value|=(uint32_t)siBytes[1]<<8;
                              value|=(uint32_t)siBytes[0]<<16;
                              length = 3;
                          }
                          prevLength=1;
                      }
                  } else {
                      if(prevLength==2) {
                          length=2;
                      } else {
                          /* change from single-byte mode to double-byte */
                          if (soLength == 1) {
                              value|=(uint32_t)soBytes[0]<<16;
                              length = 3;
                          } else if (soLength == 2) {
                              value|=(uint32_t)soBytes[1]<<16;
                              value|=(uint32_t)soBytes[0]<<24;
                              length = 4;
                          }
                          prevLength=2;
                      }
                  }
                  break;
              case MBCS_OUTPUT_DBCS_ONLY:
                  /* table with single-byte results, but only DBCS mappings used */
                  value=((const uint16_t *)bytes)[value +(c&0x3f)];
                  if(value<=0xff) {
                      /* no mapping or SBCS result, not taken for DBCS-only */
                      goto unassigned;
                  } else {
                      length=2;
                  }
                  break;
              case MBCS_OUTPUT_3:
                  p=bytes+(value+(c&0x3f))*3;
                  value=((uint32_t)*p<<16)|((uint32_t)p[1]<<8)|p[2];
                  if(value<=0xff) {
                      if(value==0) {
                          goto unassigned;
                      } else {
                          length=1;
                      }
                  } else if(value<=0xffff) {
                      length=2;
                  } else {
                      length=3;
                  }
                  break;
              case MBCS_OUTPUT_4:
                  value=((const uint32_t *)bytes)[value +(c&0x3f)];
                  if(value<=0xff) {
                      if(value==0) {
                          goto unassigned;
                      } else {
                          length=1;
                      }
                  } else if(value<=0xffff) {
                      length=2;
                  } else if(value<=0xffffff) {
                      length=3;
                  } else {
                      length=4;
                  }
                  break;
              case MBCS_OUTPUT_3_EUC:
                  value=((const uint16_t *)bytes)[value +(c&0x3f)];
                  /* EUC 16-bit fixed-length representation */
                  if(value<=0xff) {
                      if(value==0) {
                          goto unassigned;
                      } else {
                          length=1;
                      }
                  } else if((value&0x8000)==0) {
                      value|=0x8e8000;
                      length=3;
                  } else if((value&0x80)==0) {
                      value|=0x8f0080;
                      length=3;
                  } else {
                      length=2;
                  }
                  break;
              case MBCS_OUTPUT_4_EUC:
                  p=bytes+(value+(c&0x3f))*3;
                  value=((uint32_t)*p<<16)|((uint32_t)p[1]<<8)|p[2];
                  /* EUC 16-bit fixed-length representation applied to the first two bytes */
                  if(value<=0xff) {
                      if(value==0) {
                          goto unassigned;
                      } else {
                          length=1;
                      }
                  } else if(value<=0xffff) {
                      length=2;
                  } else if((value&0x800000)==0) {
                      value|=0x8e800000;
                      length=4;
                  } else if((value&0x8000)==0) {
                      value|=0x8f008000;
                      length=4;
                  } else {
                      length=3;
                  }
                  break;
              default:
                  /* must not occur */
                  /*
                   * To avoid compiler warnings that value & length may be
                   * used without having been initialized, we set them here.
                   * In reality, this is unreachable code.
                   * Not having a default branch also causes warnings with
                   * some compilers.
                   */
                  value=0;
                  length=0;
                  break;
              }
              /* output the value */
          } else {
              /*
               * This also tests if the codepage maps single surrogates.
               * If it does, then surrogates are not paired but mapped separately.
               * Note that in this case unmatched surrogates are not detected.
               */
              if(U16_IS_SURROGATE(c)(((c)&0xfffff800)==0xd800) && !(unicodeMask&UCNV_HAS_SURROGATES2)) {
                  if(U16_IS_SURROGATE_LEAD(c)(((c)&0x400)==0)) {
4390getTrail:
                      if(source<sourceLimit) {
                          /* test the following code unit */
                          UChar trail=*source;
                          if(U16_IS_TRAIL(trail)(((trail)&0xfffffc00)==0xdc00)) {
                              ++source;
                              ++nextSourceIndex;
                              c=U16_GET_SUPPLEMENTARY(c, trail)(((UChar32)(c)<<10UL)+(UChar32)(trail)-((0xd800<<
10UL)+0xdc00-0x10000));
                              if(!(unicodeMask&UCNV_HAS_SUPPLEMENTARY1)) {
                                  /* BMP-only codepages are stored without stage 1 entries for supplementary code points */
                                  cnv->fromUnicodeStatus=prevLength; /* save the old state */
                                  /* callback(unassigned) */
                                  goto unassigned;
                              }
                              /* convert this supplementary code point */
                              /* exit this condition tree */
                          } else {
                              /* this is an unmatched lead code unit (1st surrogate) */
                              /* callback(illegal) */
                              *pErrorCode=U_ILLEGAL_CHAR_FOUND;
                              break;
                          }
                      } else {
                          /* no more input */
                          break;
                      }
                  } else {
                      /* this is an unmatched trail code unit (2nd surrogate) */
                      /* callback(illegal) */
                      *pErrorCode=U_ILLEGAL_CHAR_FOUND;
                      break;
                  }
              }

              /* convert the Unicode code point in c into codepage bytes */

              /*
               * The basic lookup is a triple-stage compact array (trie) lookup.
               * For details see the beginning of this file.
               *
               * Single-byte codepages are handled with a different data structure
               * by _MBCSSingle... functions.
               *
               * The result consists of a 32-bit value from stage 2 and
               * a pointer to as many bytes as are stored per character.
               * The pointer points to the character's bytes in stage 3.
               * Bits 15..0 of the stage 2 entry contain the stage 3 index
               * for that pointer, while bits 31..16 are flags for which of
               * the 16 characters in the block are roundtrip-assigned.
               *
               * For 2-byte and 4-byte codepages, the bytes are stored as uint16_t
               * respectively as uint32_t, in the platform encoding.
               * For 3-byte codepages, the bytes are always stored in big-endian order.
               *
               * For EUC encodings that use only either 0x8e or 0x8f as the first
               * byte of their longest byte sequences, the first two bytes in
               * this third stage indicate with their 7th bits whether these bytes
               * are to be written directly or actually need to be preceded by
               * one of the two Single-Shift codes. With this, the third stage
               * stores one byte fewer per character than the actual maximum length of
               * EUC byte sequences.
               *
               * Other than that, leading zero bytes are removed and the other
               * bytes output. A single zero byte may be output if the "assigned"
               * bit in stage 2 was on.
               * The data structure does not support zero byte output as a fallback,
               * and also does not allow output of leading zeros.
               */
              stage2Entry=MBCS_STAGE_2_FROM_U(table, c)((const uint32_t *)(table))[ (table)[(c)>>10] +(((c)>>
4)&0x3f) ];

              /* get the bytes and the length for the output */
              switch(outputType) {
              case MBCS_OUTPUT_2:
                  value=MBCS_VALUE_2_FROM_STAGE_2(bytes, stage2Entry, c)((uint16_t *)(bytes))[16*(uint32_t)(uint16_t)(stage2Entry)+((
c)&0xf)];
                  if(value<=0xff) {
                      length=1;
                  } else {
                      length=2;
                  }
                  break;
              case MBCS_OUTPUT_2_SISO:
                  /* 1/2-byte stateful with Shift-In/Shift-Out */
                  /*
                   * Save the old state in the converter object
                   * right here, then change the local prevLength state variable if necessary.
                   * Then, if this character turns out to be unassigned or a fallback that
                   * is not taken, the callback code must not save the new state in the converter
                   * because the new state is for a character that is not output.
                   * However, the callback must still restore the state from the converter
                   * in case the callback function changed it for its output.
                   */
                  cnv->fromUnicodeStatus=prevLength; /* save the old state */
                  value=MBCS_VALUE_2_FROM_STAGE_2(bytes, stage2Entry, c)((uint16_t *)(bytes))[16*(uint32_t)(uint16_t)(stage2Entry)+((
c)&0xf)];
                  if(value<=0xff) {
                      if(value==0 && MBCS_FROM_U_IS_ROUNDTRIP(stage2Entry, c)( ((stage2Entry) & ((uint32_t)1<< (16+((c)&0xf)
) )) !=0)==0) {
                          /* no mapping, leave value==0 */
                          length=0;
                      } else if(prevLength<=1) {
                          length=1;
                      } else {
                          /* change from double-byte mode to single-byte */
                          if (siLength == 1) {
                              value|=(uint32_t)siBytes[0]<<8;
                              length = 2;
                          } else if (siLength == 2) {
                              value|=(uint32_t)siBytes[1]<<8;
                              value|=(uint32_t)siBytes[0]<<16;
                              length = 3;
                          }
                          prevLength=1;
                      }
                  } else {
                      if(prevLength==2) {
                          length=2;
                      } else {
                          /* change from single-byte mode to double-byte */
                          if (soLength == 1) {
                              value|=(uint32_t)soBytes[0]<<16;
                              length = 3;
                          } else if (soLength == 2) {
                              value|=(uint32_t)soBytes[1]<<16;
                              value|=(uint32_t)soBytes[0]<<24;
                              length = 4;
                          }
                          prevLength=2;
                      }
                  }
                  break;
              case MBCS_OUTPUT_DBCS_ONLY:
                  /* table with single-byte results, but only DBCS mappings used */
                  value=MBCS_VALUE_2_FROM_STAGE_2(bytes, stage2Entry, c)((uint16_t *)(bytes))[16*(uint32_t)(uint16_t)(stage2Entry)+((
c)&0xf)];
                  if(value<=0xff) {
                      /* no mapping or SBCS result, not taken for DBCS-only */
                      value=stage2Entry=0; /* stage2Entry=0 to reset roundtrip flags */
                      length=0;
                  } else {
                      length=2;
                  }
                  break;
              case MBCS_OUTPUT_3:
                  p=MBCS_POINTER_3_FROM_STAGE_2(bytes, stage2Entry, c)((bytes)+(16*(uint32_t)(uint16_t)(stage2Entry)+((c)&0xf))
*3);
                  value=((uint32_t)*p<<16)|((uint32_t)p[1]<<8)|p[2];
                  if(value<=0xff) {
                      length=1;
                  } else if(value<=0xffff) {
                      length=2;
                  } else {
                      length=3;
                  }
                  break;
              case MBCS_OUTPUT_4:
                  value=MBCS_VALUE_4_FROM_STAGE_2(bytes, stage2Entry, c)((uint32_t *)(bytes))[16*(uint32_t)(uint16_t)(stage2Entry)+((
c)&0xf)];
                  if(value<=0xff) {
                      length=1;
                  } else if(value<=0xffff) {
                      length=2;
                  } else if(value<=0xffffff) {
                      length=3;
                  } else {
                      length=4;
                  }
                  break;
              case MBCS_OUTPUT_3_EUC:
                  value=MBCS_VALUE_2_FROM_STAGE_2(bytes, stage2Entry, c)((uint16_t *)(bytes))[16*(uint32_t)(uint16_t)(stage2Entry)+((
c)&0xf)];
                  /* EUC 16-bit fixed-length representation */
                  if(value<=0xff) {
                      length=1;
                  } else if((value&0x8000)==0) {
                      value|=0x8e8000;
                      length=3;
                  } else if((value&0x80)==0) {
                      value|=0x8f0080;
                      length=3;
                  } else {
                      length=2;
                  }
                  break;
              case MBCS_OUTPUT_4_EUC:
                  p=MBCS_POINTER_3_FROM_STAGE_2(bytes, stage2Entry, c)((bytes)+(16*(uint32_t)(uint16_t)(stage2Entry)+((c)&0xf))
*3);
                  value=((uint32_t)*p<<16)|((uint32_t)p[1]<<8)|p[2];
                  /* EUC 16-bit fixed-length representation applied to the first two bytes */
                  if(value<=0xff) {
                      length=1;
                  } else if(value<=0xffff) {
                      length=2;
                  } else if((value&0x800000)==0) {
                      value|=0x8e800000;
                      length=4;
                  } else if((value&0x8000)==0) {
                      value|=0x8f008000;
                      length=4;
                  } else {
                      length=3;
                  }
                  break;
              default:
                  /* must not occur */
                  /*
                   * To avoid compiler warnings that value & length may be
                   * used without having been initialized, we set them here.
                   * In reality, this is unreachable code.
                   * Not having a default branch also causes warnings with
                   * some compilers.
                   */
                  value=stage2Entry=0; /* stage2Entry=0 to reset roundtrip flags */
                  length=0;
                  break;
              }

              /* is this code point assigned, or do we use fallbacks? */
              if(!(MBCS_FROM_U_IS_ROUNDTRIP(stage2Entry, c)( ((stage2Entry) & ((uint32_t)1<< (16+((c)&0xf)
) )) !=0)!=0 ||
                   (UCNV_FROM_U_USE_FALLBACK(cnv, c)(((cnv)->useFallback) || ((uint32_t)((c)-0xe000)<0x1900
 || (uint32_t)((c)-0xf0000)<0x20000)) && value!=0))
              ) {
                  /*
                   * We allow a 0 byte output if the "assigned" bit is set for this entry.
                   * There is no way with this data structure for fallback output
                   * to be a zero byte.
                   */

4609unassigned:
                  /* try an extension mapping */
                  pArgs->source=source;
                  c=_extFromU(cnv, cnv->sharedData,
                              c, &source, sourceLimit,
                              &target, target+targetCapacity,
                              &offsets, sourceIndex,
                              pArgs->flush,
                              pErrorCode);
                  nextSourceIndex+=(int32_t)(source-pArgs->source);
                  prevLength=cnv->fromUnicodeStatus; /* restore SISO state */

                  if(U_FAILURE(*pErrorCode)) {
                      /* not mappable or buffer overflow */
                      break;
                  } else {
                      /* a mapping was written to the target, continue */

                      /* recalculate the targetCapacity after an extension mapping */
                      targetCapacity=(int32_t)(pArgs->targetLimit-(char *)target);

                      /* normal end of conversion: prepare for a new character */
                      if(offsets!=NULL__null) {
                          prevSourceIndex=sourceIndex;
                          sourceIndex=nextSourceIndex;
                      }
                      continue;
                  }
              }
          }

          /* write the output character bytes from value and length */
          /* from the first if in the loop we know that targetCapacity>0 */
          if(length<=targetCapacity) {
              if(offsets==NULL__null) {
                  switch(length) {
                      /* each branch falls through to the next one */
                  case 4:
                      *target++=(uint8_t)(value>>24);
                      U_FALLTHROUGH[[clang::fallthrough]];
                  case 3:
                      *target++=(uint8_t)(value>>16);
                      U_FALLTHROUGH[[clang::fallthrough]];
                  case 2:
                      *target++=(uint8_t)(value>>8);
                      U_FALLTHROUGH[[clang::fallthrough]];
                  case 1:
                      *target++=(uint8_t)value;
                      U_FALLTHROUGH[[clang::fallthrough]];
                  default:
                      /* will never occur */
                      break;
                  }
              } else {
                  switch(length) {
                      /* each branch falls through to the next one */
                  case 4:
                      *target++=(uint8_t)(value>>24);
                      *offsets++=sourceIndex;
                      U_FALLTHROUGH[[clang::fallthrough]];
                  case 3:
                      *target++=(uint8_t)(value>>16);
                      *offsets++=sourceIndex;
                      U_FALLTHROUGH[[clang::fallthrough]];
                  case 2:
                      *target++=(uint8_t)(value>>8);
                      *offsets++=sourceIndex;
                      U_FALLTHROUGH[[clang::fallthrough]];
                  case 1:
                      *target++=(uint8_t)value;
                      *offsets++=sourceIndex;
                      U_FALLTHROUGH[[clang::fallthrough]];
                  default:
                      /* will never occur */
                      break;
                  }
              }
              targetCapacity-=length;
          } else {
              uint8_t *charErrorBuffer;

              /*
               * We actually do this backwards here:
               * In order to save an intermediate variable, we output
               * first to the overflow buffer what does not fit into the
               * regular target.
               */
              /* we know that 1<=targetCapacity<length<=4 */
              length-=targetCapacity;
              charErrorBuffer=(uint8_t *)cnv->charErrorBuffer;
              switch(length) {
                  /* each branch falls through to the next one */
              case 3:
                  *charErrorBuffer++=(uint8_t)(value>>16);
                  U_FALLTHROUGH[[clang::fallthrough]];
              case 2:
                  *charErrorBuffer++=(uint8_t)(value>>8);
                  U_FALLTHROUGH[[clang::fallthrough]];
              case 1:
                  *charErrorBuffer=(uint8_t)value;
                  U_FALLTHROUGH[[clang::fallthrough]];
              default:
                  /* will never occur */
                  break;
              }
              cnv->charErrorBufferLength=(int8_t)length;

              /* now output what fits into the regular target */
              value>>=8*length; /* length was reduced by targetCapacity */
              switch(targetCapacity) {
                  /* each branch falls through to the next one */
              case 3:
                  *target++=(uint8_t)(value>>16);
                  if(offsets!=NULL__null) {
                      *offsets++=sourceIndex;
                  }
                  U_FALLTHROUGH[[clang::fallthrough]];
              case 2:
                  *target++=(uint8_t)(value>>8);
                  if(offsets!=NULL__null) {
                      *offsets++=sourceIndex;
                  }
                  U_FALLTHROUGH[[clang::fallthrough]];
              case 1:
                  *target++=(uint8_t)value;
                  if(offsets!=NULL__null) {
                      *offsets++=sourceIndex;
                  }
                  U_FALLTHROUGH[[clang::fallthrough]];
              default:
                  /* will never occur */
                  break;
              }

              /* target overflow */
              targetCapacity=0;
              *pErrorCode=U_BUFFER_OVERFLOW_ERROR;
              c=0;
              break;
          }

          /* normal end of conversion: prepare for a new character */
          c=0;
          if(offsets!=NULL__null) {
              prevSourceIndex=sourceIndex;
              sourceIndex=nextSourceIndex;
          }
          continue;
      } else {
          /* target is full */
          *pErrorCode=U_BUFFER_OVERFLOW_ERROR;
          break;
      }
  }

  /*
   * the end of the input stream and detection of truncated input
   * are handled by the framework, but for EBCDIC_STATEFUL conversion
   * we need to emit an SI at the very end
   *
   * conditions:
   *   successful
   *   EBCDIC_STATEFUL in DBCS mode
   *   end of input and no truncated input
   */
  if( U_SUCCESS(*pErrorCode) &&
      outputType==MBCS_OUTPUT_2_SISO && prevLength==2 &&
      pArgs->flush && source>=sourceLimit && c==0
  ) {
      /* EBCDIC_STATEFUL ending with DBCS: emit an SI to return the output stream to SBCS */
      if(targetCapacity>0) {
          *target++=(uint8_t)siBytes[0];
          if (siLength == 2) {
              if (targetCapacity<2) {
                  cnv->charErrorBuffer[0]=(uint8_t)siBytes[1];
                  cnv->charErrorBufferLength=1;
                  *pErrorCode=U_BUFFER_OVERFLOW_ERROR;
              } else {
                  *target++=(uint8_t)siBytes[1];
              }
          }
          if(offsets!=NULL__null) {
              /* set the last source character's index (sourceIndex points at sourceLimit now) */
              *offsets++=prevSourceIndex;
          }
      } else {
          /* target is full */
          cnv->charErrorBuffer[0]=(uint8_t)siBytes[0];
          if (siLength == 2) {
              cnv->charErrorBuffer[1]=(uint8_t)siBytes[1];
          }
          cnv->charErrorBufferLength=siLength;
          *pErrorCode=U_BUFFER_OVERFLOW_ERROR;
      }
      prevLength=1; /* we switched into SBCS */
  }

  /* set the converter state back into UConverter */
  cnv->fromUChar32=c;
  cnv->fromUnicodeStatus=prevLength;

  /* write back the updated pointers */
  pArgs->source=source;
  pArgs->target=(char *)target;
  pArgs->offsets=offsets;
4814}

4816/*
* This is another simple conversion function for internal use by other
* conversion implementations.
* It does not use the converter state nor call callbacks.
* It does not handle the EBCDIC swaplfnl option (set in UConverter).
* It handles conversion extensions but not GB 18030.
*
* It converts one single Unicode code point into codepage bytes, encoded
* as one 32-bit value. The function returns the number of bytes in *pValue:
* 1..4 the number of bytes in *pValue
* 0    unassigned (*pValue undefined)
* -1   illegal (currently not used, *pValue undefined)
*
* *pValue will contain the resulting bytes with the last byte in bits 7..0,
* the second to last byte in bits 15..8, etc.
* Currently, the function assumes but does not check that 0<=c<=0x10ffff.
*/
4833U_CFUNCextern "C" int32_t
4834ucnv_MBCSFromUChar32ucnv_MBCSFromUChar32_71(UConverterSharedData *sharedData,
               UChar32 c, uint32_t *pValue,
               UBool useFallback) {
  const int32_t *cx;
  const uint16_t *table;
4839#if 0
4840/* #if 0 because this is not currently used in ICU - reduce code, increase code coverage */
  const uint8_t *p;
4842#endif
  uint32_t stage2Entry;
  uint32_t value;
  int32_t length;

  /* BMP-only codepages are stored without stage 1 entries for supplementary code points */
  if(c<=0xffff || (sharedData->mbcs.unicodeMask&UCNV_HAS_SUPPLEMENTARY1)) {
      table=sharedData->mbcs.fromUnicodeTable;

      /* convert the Unicode code point in c into codepage bytes (same as in _MBCSFromUnicodeWithOffsets) */
      if(sharedData->mbcs.outputType==MBCS_OUTPUT_1) {
          value=MBCS_SINGLE_RESULT_FROM_U(table, (uint16_t *)sharedData->mbcs.fromUnicodeBytes, c)((uint16_t *)sharedData->mbcs.fromUnicodeBytes)[ (table)[ (
table)[(c)>>10] +(((c)>>4)&0x3f) ] +((c)&
0xf) ];
          /* is this code point assigned, or do we use fallbacks? */
          if(useFallback ? value>=0x800 : value>=0xc00) {
              *pValue=value&0xff;
              return 1;
          }
      } else /* outputType!=MBCS_OUTPUT_1 */ {
          stage2Entry=MBCS_STAGE_2_FROM_U(table, c)((const uint32_t *)(table))[ (table)[(c)>>10] +(((c)>>
4)&0x3f) ];

          /* get the bytes and the length for the output */
          switch(sharedData->mbcs.outputType) {
          case MBCS_OUTPUT_2:
              value=MBCS_VALUE_2_FROM_STAGE_2(sharedData->mbcs.fromUnicodeBytes, stage2Entry, c)((uint16_t *)(sharedData->mbcs.fromUnicodeBytes))[16*(uint32_t
)(uint16_t)(stage2Entry)+((c)&0xf)];
              if(value<=0xff) {
                  length=1;
              } else {
                  length=2;
              }
              break;
4872#if 0
4873/* #if 0 because this is not currently used in ICU - reduce code, increase code coverage */
          case MBCS_OUTPUT_DBCS_ONLY:
              /* table with single-byte results, but only DBCS mappings used */
              value=MBCS_VALUE_2_FROM_STAGE_2(sharedData->mbcs.fromUnicodeBytes, stage2Entry, c)((uint16_t *)(sharedData->mbcs.fromUnicodeBytes))[16*(uint32_t
)(uint16_t)(stage2Entry)+((c)&0xf)];
              if(value<=0xff) {
                  /* no mapping or SBCS result, not taken for DBCS-only */
                  value=stage2Entry=0; /* stage2Entry=0 to reset roundtrip flags */
                  length=0;
              } else {
                  length=2;
              }
              break;
          case MBCS_OUTPUT_3:
              p=MBCS_POINTER_3_FROM_STAGE_2(sharedData->mbcs.fromUnicodeBytes, stage2Entry, c)((sharedData->mbcs.fromUnicodeBytes)+(16*(uint32_t)(uint16_t
)(stage2Entry)+((c)&0xf))*3);
              value=((uint32_t)*p<<16)|((uint32_t)p[1]<<8)|p[2];
              if(value<=0xff) {
                  length=1;
              } else if(value<=0xffff) {
                  length=2;
              } else {
                  length=3;
              }
              break;
          case MBCS_OUTPUT_4:
              value=MBCS_VALUE_4_FROM_STAGE_2(sharedData->mbcs.fromUnicodeBytes, stage2Entry, c)((uint32_t *)(sharedData->mbcs.fromUnicodeBytes))[16*(uint32_t
)(uint16_t)(stage2Entry)+((c)&0xf)];
              if(value<=0xff) {
                  length=1;
              } else if(value<=0xffff) {
                  length=2;
              } else if(value<=0xffffff) {
                  length=3;
              } else {
                  length=4;
              }
              break;
          case MBCS_OUTPUT_3_EUC:
              value=MBCS_VALUE_2_FROM_STAGE_2(sharedData->mbcs.fromUnicodeBytes, stage2Entry, c)((uint16_t *)(sharedData->mbcs.fromUnicodeBytes))[16*(uint32_t
)(uint16_t)(stage2Entry)+((c)&0xf)];
              /* EUC 16-bit fixed-length representation */
              if(value<=0xff) {
                  length=1;
              } else if((value&0x8000)==0) {
                  value|=0x8e8000;
                  length=3;
              } else if((value&0x80)==0) {
                  value|=0x8f0080;
                  length=3;
              } else {
                  length=2;
              }
              break;
          case MBCS_OUTPUT_4_EUC:
              p=MBCS_POINTER_3_FROM_STAGE_2(sharedData->mbcs.fromUnicodeBytes, stage2Entry, c)((sharedData->mbcs.fromUnicodeBytes)+(16*(uint32_t)(uint16_t
)(stage2Entry)+((c)&0xf))*3);
              value=((uint32_t)*p<<16)|((uint32_t)p[1]<<8)|p[2];
              /* EUC 16-bit fixed-length representation applied to the first two bytes */
              if(value<=0xff) {
                  length=1;
              } else if(value<=0xffff) {
                  length=2;
              } else if((value&0x800000)==0) {
                  value|=0x8e800000;
                  length=4;
              } else if((value&0x8000)==0) {
                  value|=0x8f008000;
                  length=4;
              } else {
                  length=3;
              }
              break;
4941#endif
          default:
              /* must not occur */
              return -1;
          }

          /* is this code point assigned, or do we use fallbacks? */
          if( MBCS_FROM_U_IS_ROUNDTRIP(stage2Entry, c)( ((stage2Entry) & ((uint32_t)1<< (16+((c)&0xf)
) )) !=0) ||
              (FROM_U_USE_FALLBACK(useFallback, c)((useFallback) || ((uint32_t)((c)-0xe000)<0x1900 || (uint32_t
)((c)-0xf0000)<0x20000)) && value!=0)
          ) {
              /*
               * We allow a 0 byte output if the "assigned" bit is set for this entry.
               * There is no way with this data structure for fallback output
               * to be a zero byte.
               */
              /* assigned */
              *pValue=value;
              return length;
          }
      }
  }

  cx=sharedData->mbcs.extIndexes;
  if(cx!=NULL__null) {
      length=ucnv_extSimpleMatchFromUucnv_extSimpleMatchFromU_71(cx, c, pValue, useFallback);
      return length>=0 ? length : -length;  /* return abs(length); */
  }

  /* unassigned */
  return 0;
4971}


4974#if 0
4975/*
* This function has been moved to ucnv2022.c for inlining.
* This implementation is here only for documentation purposes
*/

4980/**
* This version of ucnv_MBCSFromUChar32() is optimized for single-byte codepages.
* It does not handle the EBCDIC swaplfnl option (set in UConverter).
* It does not handle conversion extensions (_extFromU()).
*
* It returns the codepage byte for the code point, or -1 if it is unassigned.
*/
4987U_CFUNCextern "C" int32_t
4988ucnv_MBCSSingleFromUChar32(UConverterSharedData *sharedData,
                     UChar32 c,
                     UBool useFallback) {
  const uint16_t *table;
  int32_t value;

  /* BMP-only codepages are stored without stage 1 entries for supplementary code points */
  if(c>=0x10000 && !(sharedData->mbcs.unicodeMask&UCNV_HAS_SUPPLEMENTARY1)) {
      return -1;
  }

  /* convert the Unicode code point in c into codepage bytes (same as in _MBCSFromUnicodeWithOffsets) */
  table=sharedData->mbcs.fromUnicodeTable;

  /* get the byte for the output */
  value=MBCS_SINGLE_RESULT_FROM_U(table, (uint16_t *)sharedData->mbcs.fromUnicodeBytes, c)((uint16_t *)sharedData->mbcs.fromUnicodeBytes)[ (table)[ (
table)[(c)>>10] +(((c)>>4)&0x3f) ] +((c)&
0xf) ];
  /* is this code point assigned, or do we use fallbacks? */
  if(useFallback ? value>=0x800 : value>=0xc00) {
      return value&0xff;
  } else {
      return -1;
  }
5010}
5011#endif

5013/* MBCS-from-UTF-8 conversion functions ------------------------------------- */

5015/* offsets for n-byte UTF-8 sequences that were calculated with ((lead<<6)+trail)<<6+trail... */
5016static const UChar32
5017utf8_offsets[5]={ 0, 0, 0x3080, 0xE2080, 0x3C82080 };

5019static void U_CALLCONV
5020ucnv_SBCSFromUTF8(UConverterFromUnicodeArgs *pFromUArgs,
                UConverterToUnicodeArgs *pToUArgs,
                UErrorCode *pErrorCode) {
  UConverter *utf8, *cnv;
  const uint8_t *source, *sourceLimit;
  uint8_t *target;
  int32_t targetCapacity;

  const uint16_t *table, *sbcsIndex;
  const uint16_t *results;

  int8_t oldToULength, toULength, toULimit;

  UChar32 c;
  uint8_t b, t1, t2;

  uint32_t asciiRoundtrips;
  uint16_t value, minValue = 0;
  UBool hasSupplementary;

  /* set up the local pointers */
  utf8=pToUArgs->converter;
  cnv=pFromUArgs->converter;
  source=(uint8_t *)pToUArgs->source;
  sourceLimit=(uint8_t *)pToUArgs->sourceLimit;
  target=(uint8_t *)pFromUArgs->target;
  targetCapacity=(int32_t)(pFromUArgs->targetLimit-pFromUArgs->target);

  table=cnv->sharedData->mbcs.fromUnicodeTable;
  sbcsIndex=cnv->sharedData->mbcs.sbcsIndex;
  if((cnv->options&UCNV_OPTION_SWAP_LFNL0x10)!=0) {
      results=(uint16_t *)cnv->sharedData->mbcs.swapLFNLFromUnicodeBytes;
  } else {
      results=(uint16_t *)cnv->sharedData->mbcs.fromUnicodeBytes;
  }
  asciiRoundtrips=cnv->sharedData->mbcs.asciiRoundtrips;

  if(cnv->useFallback) {
      /* use all roundtrip and fallback results */
      minValue=0x800;
  } else {
      /* use only roundtrips and fallbacks from private-use characters */
      minValue=0xc00;
  }
  hasSupplementary=(UBool)(cnv->sharedData->mbcs.unicodeMask&UCNV_HAS_SUPPLEMENTARY1);

  /* get the converter state from the UTF-8 UConverter */
  if(utf8->toULength > 0) {
      toULength=oldToULength=utf8->toULength;
      toULimit=(int8_t)utf8->mode;
      c=(UChar32)utf8->toUnicodeStatus;
  } else {
      toULength=oldToULength=toULimit=0;
      c = 0;
  }

  // The conversion loop checks source<sourceLimit only once per 1/2/3-byte character.
  // If the buffer ends with a truncated 2- or 3-byte sequence,
  // then we reduce the sourceLimit to before that,
  // and collect the remaining bytes after the conversion loop.
  {
      // Do not go back into the bytes that will be read for finishing a partial
      // sequence from the previous buffer.
      int32_t length=(int32_t)(sourceLimit-source) - (toULimit-oldToULength);
      if(length>0) {
          uint8_t b1=*(sourceLimit-1);
          if(U8_IS_SINGLE(b1)(((b1)&0x80)==0)) {
              // common ASCII character
          } else if(U8_IS_TRAIL(b1)((int8_t)(b1)<-0x40) && length>=2) {
              uint8_t b2=*(sourceLimit-2);
              if(0xe0<=b2 && b2<0xf0 && U8_IS_VALID_LEAD3_AND_T1(b2, b1)("\x20\x30\x30\x30\x30\x30\x30\x30\x30\x30\x30\x30\x30\x10\x30\x30"
[(b2)&0xf]&(1<<((uint8_t)(b1)>>5)))) {
                  // truncated 3-byte sequence
                  sourceLimit-=2;
              }
          } else if(0xc2<=b1 && b1<0xf0) {
              // truncated 2- or 3-byte sequence
              --sourceLimit;
          }
      }
  }

  if(c!=0 && targetCapacity>0) {
      utf8->toUnicodeStatus=0;
      utf8->toULength=0;
      goto moreBytes;
      /*
       * Note: We could avoid the goto by duplicating some of the moreBytes
       * code, but only up to the point of collecting a complete UTF-8
       * sequence; then recurse for the toUBytes[toULength]
       * and then continue with normal conversion.
       *
       * If so, move this code to just after initializing the minimum
       * set of local variables for reading the UTF-8 input
       * (utf8, source, target, limits but not cnv, table, minValue, etc.).
       *
       * Potential advantages:
       * - avoid the goto
       * - oldToULength could become a local variable in just those code blocks
       *   that deal with buffer boundaries
       * - possibly faster if the goto prevents some compiler optimizations
       *   (this would need measuring to confirm)
       * Disadvantage:
       * - code duplication
       */
  }

  /* conversion loop */
  while(source<sourceLimit) {
      if(targetCapacity>0) {
          b=*source++;
          if(U8_IS_SINGLE(b)(((b)&0x80)==0)) {
              /* convert ASCII */
              if(IS_ASCII_ROUNDTRIP(b, asciiRoundtrips)(((asciiRoundtrips) & (1<<((b)>>2)))!=0)) {
                  *target++=(uint8_t)b;
                  --targetCapacity;
                  continue;
              } else {
                  c=b;
                  value=SBCS_RESULT_FROM_UTF8(sbcsIndex, results, 0, c)(results)[ (sbcsIndex)[0] +(c) ];
              }
          } else {
              if(b<0xe0) {
                  if( /* handle U+0080..U+07FF inline */
                      b>=0xc2 &&
                      (t1=(uint8_t)(*source-0x80)) <= 0x3f
                  ) {
                      c=b&0x1f;
                      ++source;
                      value=SBCS_RESULT_FROM_UTF8(sbcsIndex, results, c, t1)(results)[ (sbcsIndex)[c] +(t1) ];
                      if(value>=minValue) {
                          *target++=(uint8_t)value;
                          --targetCapacity;
                          continue;
                      } else {
                          c=(c<<6)|t1;
                      }
                  } else {
                      c=-1;
                  }
              } else if(b==0xe0) {
                  if( /* handle U+0800..U+0FFF inline */
                      (t1=(uint8_t)(source[0]-0x80)) <= 0x3f && t1 >= 0x20 &&
                      (t2=(uint8_t)(source[1]-0x80)) <= 0x3f
                  ) {
                      c=t1;
                      source+=2;
                      value=SBCS_RESULT_FROM_UTF8(sbcsIndex, results, c, t2)(results)[ (sbcsIndex)[c] +(t2) ];
                      if(value>=minValue) {
                          *target++=(uint8_t)value;
                          --targetCapacity;
                          continue;
                      } else {
                          c=(c<<6)|t2;
                      }
                  } else {
                      c=-1;
                  }
              } else {
                  c=-1;
              }

              if(c<0) {
                  /* handle "complicated" and error cases, and continuing partial characters */
                  oldToULength=0;
                  toULength=1;
                  toULimit=U8_COUNT_BYTES_NON_ASCII(b)(((uint8_t)((b)-0xc2)<=0x32) ? ((uint8_t)(b)>=0xe0)+((uint8_t
)(b)>=0xf0)+2 : 0);
                  c=b;
5187moreBytes:
                  while(toULength<toULimit) {
                      /*
                       * The sourceLimit may have been adjusted before the conversion loop
                       * to stop before a truncated sequence.
                       * Here we need to use the real limit in case we have two truncated
                       * sequences at the end.
                       * See ticket #7492.
                       */
                      if(source<(uint8_t *)pToUArgs->sourceLimit) {
                          b=*source;
                          if(icu::UTF8::isValidTrail(c, b, toULength, toULimit)) {
                              ++source;
                              ++toULength;
                              c=(c<<6)+b;
                          } else {
                              break; /* sequence too short, stop with toULength<toULimit */
                          }
                      } else {
                          /* store the partial UTF-8 character, compatible with the regular UTF-8 converter */
                          source-=(toULength-oldToULength);
                          while(oldToULength<toULength) {
                              utf8->toUBytes[oldToULength++]=*source++;
                          }
                          utf8->toUnicodeStatus=c;
                          utf8->toULength=toULength;
                          utf8->mode=toULimit;
                          pToUArgs->source=(char *)source;
                          pFromUArgs->target=(char *)target;
                          return;
                      }
                  }

                  if(toULength==toULimit) {
                      c-=utf8_offsets[toULength];
                      if(toULength<=3) {  /* BMP */
                          value=MBCS_SINGLE_RESULT_FROM_U(table, results, c)(results)[ (table)[ (table)[(c)>>10] +(((c)>>4)&
0x3f) ] +((c)&0xf) ];
                      } else {
                          /* supplementary code point */
                          if(!hasSupplementary) {
                              /* BMP-only codepages are stored without stage 1 entries for supplementary code points */
                              value=0;
                          } else {
                              value=MBCS_SINGLE_RESULT_FROM_U(table, results, c)(results)[ (table)[ (table)[(c)>>10] +(((c)>>4)&
0x3f) ] +((c)&0xf) ];
                          }
                      }
                  } else {
                      /* error handling: illegal UTF-8 byte sequence */
                      source-=(toULength-oldToULength);
                      while(oldToULength<toULength) {
                          utf8->toUBytes[oldToULength++]=*source++;
                      }
                      utf8->toULength=toULength;
                      pToUArgs->source=(char *)source;
                      pFromUArgs->target=(char *)target;
                      *pErrorCode=U_ILLEGAL_CHAR_FOUND;
                      return;
                  }
              }
          }

          if(value>=minValue) {
              /* output the mapping for c */
              *target++=(uint8_t)value;
              --targetCapacity;
          } else {
              /* value<minValue means c is unassigned (unmappable) */
              /*
               * Try an extension mapping.
               * Pass in no source because we don't have UTF-16 input.
               * If we have a partial match on c, we will return and revert
               * to UTF-8->UTF-16->charset conversion.
               */
              static const UChar nul=0;
              const UChar *noSource=&nul;
              c=_extFromU(cnv, cnv->sharedData,
                          c, &noSource, noSource,
                          &target, target+targetCapacity,
                          NULL__null, -1,
                          pFromUArgs->flush,
                          pErrorCode);

              if(U_FAILURE(*pErrorCode)) {
                  /* not mappable or buffer overflow */
                  cnv->fromUChar32=c;
                  break;
              } else if(cnv->preFromUFirstCP>=0) {
                  /*
                   * Partial match, return and revert to pivoting.
                   * In normal from-UTF-16 conversion, we would just continue
                   * but then exit the loop because the extension match would
                   * have consumed the source.
                   */
                  *pErrorCode=U_USING_DEFAULT_WARNING;
                  break;
              } else {
                  /* a mapping was written to the target, continue */

                  /* recalculate the targetCapacity after an extension mapping */
                  targetCapacity=(int32_t)(pFromUArgs->targetLimit-(char *)target);
              }
          }
      } else {
          /* target is full */
          *pErrorCode=U_BUFFER_OVERFLOW_ERROR;
          break;
      }
  }

  /*
   * The sourceLimit may have been adjusted before the conversion loop
   * to stop before a truncated sequence.
   * If so, then collect the truncated sequence now.
   */
  if(U_SUCCESS(*pErrorCode) &&
          cnv->preFromUFirstCP<0 &&
          source<(sourceLimit=(uint8_t *)pToUArgs->sourceLimit)) {
      c=utf8->toUBytes[0]=b=*source++;
      toULength=1;
      toULimit=U8_COUNT_BYTES(b)((((b)&0x80)==0) ? 1 : (((uint8_t)((b)-0xc2)<=0x32) ? (
(uint8_t)(b)>=0xe0)+((uint8_t)(b)>=0xf0)+2 : 0));
      while(source<sourceLimit) {
          utf8->toUBytes[toULength++]=b=*source++;
          c=(c<<6)+b;
      }
      utf8->toUnicodeStatus=c;
      utf8->toULength=toULength;
      utf8->mode=toULimit;
  }

  /* write back the updated pointers */
  pToUArgs->source=(char *)source;
  pFromUArgs->target=(char *)target;
5319}

5321static void U_CALLCONV
5322ucnv_DBCSFromUTF8(UConverterFromUnicodeArgs *pFromUArgs,
                UConverterToUnicodeArgs *pToUArgs,
                UErrorCode *pErrorCode) {
  UConverter *utf8, *cnv;
  const uint8_t *source, *sourceLimit;
  uint8_t *target;
  int32_t targetCapacity;

  const uint16_t *table, *mbcsIndex;
  const uint16_t *results;

  int8_t oldToULength, toULength, toULimit;

  UChar32 c;
  uint8_t b, t1, t2;

  uint32_t stage2Entry;
  uint32_t asciiRoundtrips;
  uint16_t value = 0;
  UBool hasSupplementary;

  /* set up the local pointers */
  utf8=pToUArgs->converter;
  cnv=pFromUArgs->converter;
  source=(uint8_t *)pToUArgs->source;
  sourceLimit=(uint8_t *)pToUArgs->sourceLimit;
  target=(uint8_t *)pFromUArgs->target;
  targetCapacity=(int32_t)(pFromUArgs->targetLimit-pFromUArgs->target);

  table=cnv->sharedData->mbcs.fromUnicodeTable;
  mbcsIndex=cnv->sharedData->mbcs.mbcsIndex;
  if((cnv->options&UCNV_OPTION_SWAP_LFNL0x10)!=0) {
1
Assuming the condition is false→
2
←
Taking false branch→
      results=(uint16_t *)cnv->sharedData->mbcs.swapLFNLFromUnicodeBytes;
  } else {
      results=(uint16_t *)cnv->sharedData->mbcs.fromUnicodeBytes;
  }
  asciiRoundtrips=cnv->sharedData->mbcs.asciiRoundtrips;

  hasSupplementary=(UBool)(cnv->sharedData->mbcs.unicodeMask&UCNV_HAS_SUPPLEMENTARY1);

  /* get the converter state from the UTF-8 UConverter */
  if(utf8->toULength > 0) {
3
←
Assuming field 'toULength' is <= 0→
4
←
Taking false branch→
      toULength=oldToULength=utf8->toULength;
      toULimit=(int8_t)utf8->mode;
      c=(UChar32)utf8->toUnicodeStatus;
  } else {
      toULength=oldToULength=toULimit=0;
      c = 0;
  }

  // The conversion loop checks source<sourceLimit only once per 1/2/3-byte character.
  // If the buffer ends with a truncated 2- or 3-byte sequence,
  // then we reduce the sourceLimit to before that,
  // and collect the remaining bytes after the conversion loop.
  {
      // Do not go back into the bytes that will be read for finishing a partial
      // sequence from the previous buffer.
      int32_t length=(int32_t)(sourceLimit-source) - (toULimit-oldToULength);
      if(length>0) {
5
←
Assuming 'length' is > 0→
6
←
Taking true branch→
          uint8_t b1=*(sourceLimit-1);
          if(U8_IS_SINGLE(b1)(((b1)&0x80)==0)) {
7
←
Assuming the condition is true→
              // common ASCII character
          } else if(U8_IS_TRAIL(b1)((int8_t)(b1)<-0x40) && length>=2) {
              uint8_t b2=*(sourceLimit-2);
              if(0xe0<=b2 && b2<0xf0 && U8_IS_VALID_LEAD3_AND_T1(b2, b1)("\x20\x30\x30\x30\x30\x30\x30\x30\x30\x30\x30\x30\x30\x10\x30\x30"
[(b2)&0xf]&(1<<((uint8_t)(b1)>>5)))) {
                  // truncated 3-byte sequence
                  sourceLimit-=2;
              }
          } else if(0xc2<=b1 && b1<0xf0) {
              // truncated 2- or 3-byte sequence
              --sourceLimit;
          }
      }
  }

  if(c7.1
'c' is equal to 0
!=0 && targetCapacity>0) {
      utf8->toUnicodeStatus=0;
      utf8->toULength=0;
      goto moreBytes;
      /* See note in ucnv_SBCSFromUTF8() about this goto. */
  }

  /* conversion loop */
  while(source7.2
'source' is < 'sourceLimit'
<sourceLimit) {
8
←
Loop condition is true.  Entering loop body→
      if(targetCapacity>0) {
9
←
Assuming 'targetCapacity' is > 0→
10
←
Taking true branch→
          b=*source++;
          if(U8_IS_SINGLE(b)(((b)&0x80)==0)) {
11
←
Assuming the condition is true→
12
←
Taking true branch→
              /* convert ASCII */
              if(IS_ASCII_ROUNDTRIP(b, asciiRoundtrips)(((asciiRoundtrips) & (1<<((b)>>2)))!=0)) {
13
←
Assuming the condition is false→
14
←
Taking false branch→
                  *target++=b;
                  --targetCapacity;
                  continue;
              } else {
                  value=DBCS_RESULT_FROM_UTF8(mbcsIndex, results, 0, b)(results)[ (mbcsIndex)[0] +(b) ];
                  if(value==0) {
15
←
Assuming 'value' is equal to 0→
16
←
Taking true branch→
                      c=b;
                      goto unassigned;
17
←
Control jumps to line 5563→
                  }
              }
          } else {
              if(b>=0xe0) {
                  if( /* handle U+0800..U+D7FF inline */
                      b<=0xed &&  // do not assume maxFastUChar>0xd7ff
                      U8_IS_VALID_LEAD3_AND_T1(b, t1=source[0])("\x20\x30\x30\x30\x30\x30\x30\x30\x30\x30\x30\x30\x30\x10\x30\x30"
[(b)&0xf]&(1<<((uint8_t)(t1=source[0])>>5
))) &&
                      (t2=(uint8_t)(source[1]-0x80)) <= 0x3f
                  ) {
                      c=((b&0xf)<<6)|(t1&0x3f);
                      source+=2;
                      value=DBCS_RESULT_FROM_UTF8(mbcsIndex, results, c, t2)(results)[ (mbcsIndex)[c] +(t2) ];
                      if(value==0) {
                          c=(c<<6)|t2;
                          goto unassigned;
                      }
                  } else {
                      c=-1;
                  }
              } else {
                  if( /* handle U+0080..U+07FF inline */
                      b>=0xc2 &&
                      (t1=(uint8_t)(*source-0x80)) <= 0x3f
                  ) {
                      c=b&0x1f;
                      ++source;
                      value=DBCS_RESULT_FROM_UTF8(mbcsIndex, results, c, t1)(results)[ (mbcsIndex)[c] +(t1) ];
                      if(value==0) {
                          c=(c<<6)|t1;
                          goto unassigned;
                      }
                  } else {
                      c=-1;
                  }
              }

              if(c<0) {
                  /* handle "complicated" and error cases, and continuing partial characters */
                  oldToULength=0;
                  toULength=1;
                  toULimit=U8_COUNT_BYTES_NON_ASCII(b)(((uint8_t)((b)-0xc2)<=0x32) ? ((uint8_t)(b)>=0xe0)+((uint8_t
)(b)>=0xf0)+2 : 0);
                  c=b;
5461moreBytes:
                  while(toULength<toULimit) {
                      /*
                       * The sourceLimit may have been adjusted before the conversion loop
                       * to stop before a truncated sequence.
                       * Here we need to use the real limit in case we have two truncated
                       * sequences at the end.
                       * See ticket #7492.
                       */
                      if(source<(uint8_t *)pToUArgs->sourceLimit) {
                          b=*source;
                          if(icu::UTF8::isValidTrail(c, b, toULength, toULimit)) {
                              ++source;
                              ++toULength;
                              c=(c<<6)+b;
                          } else {
                              break; /* sequence too short, stop with toULength<toULimit */
                          }
                      } else {
                          /* store the partial UTF-8 character, compatible with the regular UTF-8 converter */
                          source-=(toULength-oldToULength);
                          while(oldToULength<toULength) {
                              utf8->toUBytes[oldToULength++]=*source++;
                          }
                          utf8->toUnicodeStatus=c;
                          utf8->toULength=toULength;
                          utf8->mode=toULimit;
                          pToUArgs->source=(char *)source;
                          pFromUArgs->target=(char *)target;
                          return;
                      }
                  }

                  if(toULength==toULimit) {
                      c-=utf8_offsets[toULength];
                      if(toULength<=3) {  /* BMP */
                          stage2Entry=MBCS_STAGE_2_FROM_U(table, c)((const uint32_t *)(table))[ (table)[(c)>>10] +(((c)>>
4)&0x3f) ];
                      } else {
                          /* supplementary code point */
                          if(!hasSupplementary) {
                              /* BMP-only codepages are stored without stage 1 entries for supplementary code points */
                              stage2Entry=0;
                          } else {
                              stage2Entry=MBCS_STAGE_2_FROM_U(table, c)((const uint32_t *)(table))[ (table)[(c)>>10] +(((c)>>
4)&0x3f) ];
                          }
                      }
                  } else {
                      /* error handling: illegal UTF-8 byte sequence */
                      source-=(toULength-oldToULength);
                      while(oldToULength<toULength) {
                          utf8->toUBytes[oldToULength++]=*source++;
                      }
                      utf8->toULength=toULength;
                      pToUArgs->source=(char *)source;
                      pFromUArgs->target=(char *)target;
                      *pErrorCode=U_ILLEGAL_CHAR_FOUND;
                      return;
                  }

                  /* get the bytes and the length for the output */
                  /* MBCS_OUTPUT_2 */
                  value=MBCS_VALUE_2_FROM_STAGE_2(results, stage2Entry, c)((uint16_t *)(results))[16*(uint32_t)(uint16_t)(stage2Entry)+
((c)&0xf)];

                  /* is this code point assigned, or do we use fallbacks? */
                  if(!(MBCS_FROM_U_IS_ROUNDTRIP(stage2Entry, c)( ((stage2Entry) & ((uint32_t)1<< (16+((c)&0xf)
) )) !=0) ||
                       (UCNV_FROM_U_USE_FALLBACK(cnv, c)(((cnv)->useFallback) || ((uint32_t)((c)-0xe000)<0x1900
 || (uint32_t)((c)-0xf0000)<0x20000)) && value!=0))
                  ) {
                      goto unassigned;
                  }
              }
          }

          /* write the output character bytes from value and length */
          /* from the first if in the loop we know that targetCapacity>0 */
          if(value<=0xff) {
              /* this is easy because we know that there is enough space */
              *target++=(uint8_t)value;
              --targetCapacity;
          } else /* length==2 */ {
              *target++=(uint8_t)(value>>8);
              if(2<=targetCapacity) {
                  *target++=(uint8_t)value;
                  targetCapacity-=2;
              } else {
                  cnv->charErrorBuffer[0]=(char)value;
                  cnv->charErrorBufferLength=1;

                  /* target overflow */
                  *pErrorCode=U_BUFFER_OVERFLOW_ERROR;
                  break;
              }
          }
          continue;

5555unassigned:
          {
              /*
               * Try an extension mapping.
               * Pass in no source because we don't have UTF-16 input.
               * If we have a partial match on c, we will return and revert
               * to UTF-8->UTF-16->charset conversion.
               */
              static const UChar nul=0;
              const UChar *noSource=&nul;
              c=_extFromU(cnv, cnv->sharedData,
18
←
Calling '_extFromU'→
                          c, &noSource, noSource,
                          &target, target+targetCapacity,
                          NULL__null, -1,
                          pFromUArgs->flush,
                          pErrorCode);

              if(U_FAILURE(*pErrorCode)) {
                  /* not mappable or buffer overflow */
                  cnv->fromUChar32=c;
                  break;
              } else if(cnv->preFromUFirstCP>=0) {
                  /*
                   * Partial match, return and revert to pivoting.
                   * In normal from-UTF-16 conversion, we would just continue
                   * but then exit the loop because the extension match would
                   * have consumed the source.
                   */
                  *pErrorCode=U_USING_DEFAULT_WARNING;
                  break;
              } else {
                  /* a mapping was written to the target, continue */

                  /* recalculate the targetCapacity after an extension mapping */
                  targetCapacity=(int32_t)(pFromUArgs->targetLimit-(char *)target);
                  continue;
              }
          }
      } else {
          /* target is full */
          *pErrorCode=U_BUFFER_OVERFLOW_ERROR;
          break;
      }
  }

  /*
   * The sourceLimit may have been adjusted before the conversion loop
   * to stop before a truncated sequence.
   * If so, then collect the truncated sequence now.
   */
  if(U_SUCCESS(*pErrorCode) &&
          cnv->preFromUFirstCP<0 &&
          source<(sourceLimit=(uint8_t *)pToUArgs->sourceLimit)) {
      c=utf8->toUBytes[0]=b=*source++;
      toULength=1;
      toULimit=U8_COUNT_BYTES(b)((((b)&0x80)==0) ? 1 : (((uint8_t)((b)-0xc2)<=0x32) ? (
(uint8_t)(b)>=0xe0)+((uint8_t)(b)>=0xf0)+2 : 0));
      while(source<sourceLimit) {
          utf8->toUBytes[toULength++]=b=*source++;
          c=(c<<6)+b;
      }
      utf8->toUnicodeStatus=c;
      utf8->toULength=toULength;
      utf8->mode=toULimit;
  }

  /* write back the updated pointers */
  pToUArgs->source=(char *)source;
  pFromUArgs->target=(char *)target;
5623}

5625/* miscellaneous ------------------------------------------------------------ */

5627static void U_CALLCONV
5628ucnv_MBCSGetStarters(const UConverter* cnv,
               UBool starters[256],
               UErrorCode *) {
  const int32_t *state0;
  int i;

  state0=cnv->sharedData->mbcs.stateTable[cnv->sharedData->mbcs.dbcsOnlyState];
  for(i=0; i<256; ++i) {
      /* all bytes that cause a state transition from state 0 are lead bytes */
      starters[i]= (UBool)MBCS_ENTRY_IS_TRANSITION(state0[i])((state0[i])>=0);
  }
5639}

5641/*
* This is an internal function that allows other converter implementations
* to check whether a byte is a lead byte.
*/
5645U_CFUNCextern "C" UBool
5646ucnv_MBCSIsLeadByteucnv_MBCSIsLeadByte_71(UConverterSharedData *sharedData, char byte) {
  return (UBool)MBCS_ENTRY_IS_TRANSITION(sharedData->mbcs.stateTable[0][(uint8_t)byte])((sharedData->mbcs.stateTable[0][(uint8_t)byte])>=0);
5648}

5650static void U_CALLCONV
5651ucnv_MBCSWriteSub(UConverterFromUnicodeArgs *pArgs,
            int32_t offsetIndex,
            UErrorCode *pErrorCode) {
  UConverter *cnv=pArgs->converter;
  char *p, *subchar;
  char buffer[4];
  int32_t length;

  /* first, select between subChar and subChar1 */
  if( cnv->subChar1!=0 &&
      (cnv->sharedData->mbcs.extIndexes!=NULL__null ?
          cnv->useSubChar1 :
          (cnv->invalidUCharBuffer[0]<=0xff))
  ) {
      /* select subChar1 if it is set (not 0) and the unmappable Unicode code point is up to U+00ff (IBM MBCS behavior) */
      subchar=(char *)&cnv->subChar1;
      length=1;
  } else {
      /* select subChar in all other cases */
      subchar=(char *)cnv->subChars;
      length=cnv->subCharLen;
  }

  /* reset the selector for the next code point */
  cnv->useSubChar1=FALSE0;

  if (cnv->sharedData->mbcs.outputType == MBCS_OUTPUT_2_SISO) {
      p=buffer;

      /* fromUnicodeStatus contains prevLength */
      switch(length) {
      case 1:
          if(cnv->fromUnicodeStatus==2) {
              /* DBCS mode and SBCS sub char: change to SBCS */
              cnv->fromUnicodeStatus=1;
              *p++=UCNV_SI0x0F;
          }
          *p++=subchar[0];
          break;
      case 2:
          if(cnv->fromUnicodeStatus<=1) {
              /* SBCS mode and DBCS sub char: change to DBCS */
              cnv->fromUnicodeStatus=2;
              *p++=UCNV_SO0x0E;
          }
          *p++=subchar[0];
          *p++=subchar[1];
          break;
      default:
          *pErrorCode=U_ILLEGAL_ARGUMENT_ERROR;
          return;
      }
      subchar=buffer;
      length=(int32_t)(p-buffer);
  }

  ucnv_cbFromUWriteBytesucnv_cbFromUWriteBytes_71(pArgs, subchar, length, offsetIndex, pErrorCode);
5708}

5710U_CFUNCextern "C" UConverterType
5711ucnv_MBCSGetTypeucnv_MBCSGetType_71(const UConverter* converter) {
  /* SBCS, DBCS, and EBCDIC_STATEFUL are replaced by MBCS, but here we cheat a little */
  if(converter->sharedData->mbcs.countStates==1) {
      return (UConverterType)UCNV_SBCS;
  } else if((converter->sharedData->mbcs.outputType&0xff)==MBCS_OUTPUT_2_SISO) {
      return (UConverterType)UCNV_EBCDIC_STATEFUL;
  } else if(converter->sharedData->staticData->minBytesPerChar==2 && converter->sharedData->staticData->maxBytesPerChar==2) {
      return (UConverterType)UCNV_DBCS;
  }
  return (UConverterType)UCNV_MBCS;
5721}

5723#endif /* #if !UCONFIG_NO_LEGACY_CONVERSION */