../deps/brotli/c/enc/./histogram

Bug Summary

File:	out/../deps/brotli/c/enc/./histogram_inc.h
Warning:	line 19, column 3 Null pointer passed to 1st parameter expecting 'nonnull'

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clang -cc1 -cc1 -triple x86_64-unknown-linux-gnu -analyze -disable-free -clear-ast-before-backend -disable-llvm-verifier -discard-value-names -main-file-name metablock.c -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -mrelocation-model pic -pic-level 2 -pic-is-pie -mframe-pointer=all -fmath-errno -ffp-contract=on -fno-rounding-math -mconstructor-aliases -funwind-tables=2 -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -fcoverage-compilation-dir=/home/maurizio/node-v18.6.0/out -resource-dir /usr/local/lib/clang/16.0.0 -D V8_DEPRECATION_WARNINGS -D V8_IMMINENT_DEPRECATION_WARNINGS -D _GLIBCXX_USE_CXX11_ABI=1 -D NODE_OPENSSL_CONF_NAME=nodejs_conf -D NODE_OPENSSL_HAS_QUIC -D __STDC_FORMAT_MACROS -D OPENSSL_NO_PINSHARED -D OPENSSL_THREADS -D OS_LINUX -I ../deps/brotli/c/include -internal-isystem /usr/local/lib/clang/16.0.0/include -internal-isystem /usr/local/include -internal-isystem /usr/lib/gcc/x86_64-redhat-linux/8/../../../../x86_64-redhat-linux/include -internal-externc-isystem /include -internal-externc-isystem /usr/include -O3 -Wno-unused-parameter -fdebug-compilation-dir=/home/maurizio/node-v18.6.0/out -ferror-limit 19 -fgnuc-version=4.2.1 -vectorize-loops -vectorize-slp -analyzer-output=html -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /tmp/scan-build-2022-08-22-142216-507842-1 -x c ../deps/brotli/c/enc/metablock.c

../deps/brotli/c/enc/metablock.c

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1/* Copyright 2015 Google Inc. All Rights Reserved.

 Distributed under MIT license.
 See file LICENSE for detail or copy at https://opensource.org/licenses/MIT
5*/

7/* Algorithms for distributing the literals and commands of a metablock between
 block types and contexts. */

10#include "./metablock.h"

12#include "../common/constants.h"
13#include "../common/context.h"
14#include "../common/platform.h"
15#include <brotli/types.h>
16#include "./bit_cost.h"
17#include "./block_splitter.h"
18#include "./cluster.h"
19#include "./entropy_encode.h"
20#include "./histogram.h"
21#include "./memory.h"
22#include "./quality.h"

24#if defined(__cplusplus) || defined(c_plusplus)
25extern "C" {
26#endif

28void BrotliInitDistanceParams(BrotliEncoderParams* params,
  uint32_t npostfix, uint32_t ndirect) {
BrotliDistanceParams* dist_params = &params->dist;
uint32_t alphabet_size_max;
uint32_t alphabet_size_limit;
uint32_t max_distance;

dist_params->distance_postfix_bits = npostfix;
dist_params->num_direct_distance_codes = ndirect;

alphabet_size_max = BROTLI_DISTANCE_ALPHABET_SIZE(( 16 + (ndirect) + ((24U) << ((npostfix) + 1)))
    npostfix, ndirect, BROTLI_MAX_DISTANCE_BITS)( 16 + (ndirect) + ((24U) << ((npostfix) + 1)));
alphabet_size_limit = alphabet_size_max;
max_distance = ndirect + (1U << (BROTLI_MAX_DISTANCE_BITS24U + npostfix + 2)) -
    (1U << (npostfix + 2));

if (params->large_window) {
  BrotliDistanceCodeLimit limit = BrotliCalculateDistanceCodeLimit(
      BROTLI_MAX_ALLOWED_DISTANCE0x7FFFFFFC, npostfix, ndirect);
  alphabet_size_max = BROTLI_DISTANCE_ALPHABET_SIZE(( 16 + (ndirect) + ((62U) << ((npostfix) + 1)))
      npostfix, ndirect, BROTLI_LARGE_MAX_DISTANCE_BITS)( 16 + (ndirect) + ((62U) << ((npostfix) + 1)));
  alphabet_size_limit = limit.max_alphabet_size;
  max_distance = limit.max_distance;
}

dist_params->alphabet_size_max = alphabet_size_max;
dist_params->alphabet_size_limit = alphabet_size_limit;
dist_params->max_distance = max_distance;
56}

58static void RecomputeDistancePrefixes(Command* cmds,
                                    size_t num_commands,
                                    const BrotliDistanceParams* orig_params,
                                    const BrotliDistanceParams* new_params) {
size_t i;

if (orig_params->distance_postfix_bits == new_params->distance_postfix_bits &&
    orig_params->num_direct_distance_codes ==
    new_params->num_direct_distance_codes) {
  return;
}

for (i = 0; i < num_commands; ++i) {
  Command* cmd = &cmds[i];
  if (CommandCopyLen(cmd) && cmd->cmd_prefix_ >= 128) {
    PrefixEncodeCopyDistance(CommandRestoreDistanceCode(cmd, orig_params),
                             new_params->num_direct_distance_codes,
                             new_params->distance_postfix_bits,
                             &cmd->dist_prefix_,
                             &cmd->dist_extra_);
  }
}
80}

82static BROTLI_BOOLint ComputeDistanceCost(const Command* cmds,
                                     size_t num_commands,
                                     const BrotliDistanceParams* orig_params,
                                     const BrotliDistanceParams* new_params,
                                     double* cost) {
size_t i;
BROTLI_BOOLint equal_params = BROTLI_FALSE0;
uint16_t dist_prefix;
uint32_t dist_extra;
double extra_bits = 0.0;
HistogramDistance histo;
HistogramClearDistance(&histo);

if (orig_params->distance_postfix_bits == new_params->distance_postfix_bits &&
    orig_params->num_direct_distance_codes ==
    new_params->num_direct_distance_codes) {
  equal_params = BROTLI_TRUE1;
}

for (i = 0; i < num_commands; i++) {
  const Command* cmd = &cmds[i];
  if (CommandCopyLen(cmd) && cmd->cmd_prefix_ >= 128) {
    if (equal_params) {
      dist_prefix = cmd->dist_prefix_;
    } else {
      uint32_t distance = CommandRestoreDistanceCode(cmd, orig_params);
      if (distance > new_params->max_distance) {
        return BROTLI_FALSE0;
      }
      PrefixEncodeCopyDistance(distance,
                               new_params->num_direct_distance_codes,
                               new_params->distance_postfix_bits,
                               &dist_prefix,
                               &dist_extra);
    }
    HistogramAddDistance(&histo, dist_prefix & 0x3FF);
    extra_bits += dist_prefix >> 10;
  }
}

*cost = BrotliPopulationCostDistance(&histo) + extra_bits;
return BROTLI_TRUE1;
124}

126void BrotliBuildMetaBlock(MemoryManager* m,
                        const uint8_t* ringbuffer,
                        const size_t pos,
                        const size_t mask,
                        BrotliEncoderParams* params,
                        uint8_t prev_byte,
                        uint8_t prev_byte2,
                        Command* cmds,
                        size_t num_commands,
                        ContextType literal_context_mode,
                        MetaBlockSplit* mb) {
/* Histogram ids need to fit in one byte. */
static const size_t kMaxNumberOfHistograms = 256;
HistogramDistance* distance_histograms;
HistogramLiteral* literal_histograms;
ContextType* literal_context_modes = NULL((void*)0);
size_t literal_histograms_size;
size_t distance_histograms_size;
size_t i;
size_t literal_context_multiplier = 1;
uint32_t npostfix;
uint32_t ndirect_msb = 0;
BROTLI_BOOLint check_orig = BROTLI_TRUE1;
double best_dist_cost = 1e99;
BrotliEncoderParams orig_params = *params;
BrotliEncoderParams new_params = *params;

for (npostfix = 0; npostfix <= BROTLI_MAX_NPOSTFIX3; npostfix++) {
  for (; ndirect_msb < 16; ndirect_msb++) {
    uint32_t ndirect = ndirect_msb << npostfix;
    BROTLI_BOOLint skip;
    double dist_cost;
    BrotliInitDistanceParams(&new_params, npostfix, ndirect);
    if (npostfix == orig_params.dist.distance_postfix_bits &&
        ndirect == orig_params.dist.num_direct_distance_codes) {
      check_orig = BROTLI_FALSE0;
    }
    skip = !ComputeDistanceCost(
        cmds, num_commands,
        &orig_params.dist, &new_params.dist, &dist_cost);
    if (skip || (dist_cost > best_dist_cost)) {
      break;
    }
    best_dist_cost = dist_cost;
    params->dist = new_params.dist;
  }
  if (ndirect_msb > 0) ndirect_msb--;
  ndirect_msb /= 2;
}
if (check_orig) {
  double dist_cost;
  ComputeDistanceCost(cmds, num_commands,
                      &orig_params.dist, &orig_params.dist, &dist_cost);
  if (dist_cost < best_dist_cost) {
    /* NB: currently unused; uncomment when more param tuning is added. */
    /* best_dist_cost = dist_cost; */
    params->dist = orig_params.dist;
  }
}
RecomputeDistancePrefixes(cmds, num_commands,
                          &orig_params.dist, &params->dist);

BrotliSplitBlock(m, cmds, num_commands,
                 ringbuffer, pos, mask, params,
                 &mb->literal_split,
                 &mb->command_split,
                 &mb->distance_split);
if (BROTLI_IS_OOM(m)(!!0)) return;

if (!params->disable_literal_context_modeling) {
  literal_context_multiplier = 1 << BROTLI_LITERAL_CONTEXT_BITS6;
  literal_context_modes =
      BROTLI_ALLOC(m, ContextType, mb->literal_split.num_types)((mb->literal_split.num_types) > 0 ? ((ContextType*)BrotliAllocate
((m), (mb->literal_split.num_types) * sizeof(ContextType))
) : ((void*)0));
  if (BROTLI_IS_OOM(m)(!!0) || BROTLI_IS_NULL(literal_context_modes)(!!0)) return;
  for (i = 0; i < mb->literal_split.num_types; ++i) {
    literal_context_modes[i] = literal_context_mode;
  }
}

literal_histograms_size =
    mb->literal_split.num_types * literal_context_multiplier;
literal_histograms =
    BROTLI_ALLOC(m, HistogramLiteral, literal_histograms_size)((literal_histograms_size) > 0 ? ((HistogramLiteral*)BrotliAllocate
((m), (literal_histograms_size) * sizeof(HistogramLiteral))) :
 ((void*)0));
if (BROTLI_IS_OOM(m)(!!0) || BROTLI_IS_NULL(literal_histograms)(!!0)) return;
ClearHistogramsLiteral(literal_histograms, literal_histograms_size);

distance_histograms_size =
    mb->distance_split.num_types << BROTLI_DISTANCE_CONTEXT_BITS2;
distance_histograms =
    BROTLI_ALLOC(m, HistogramDistance, distance_histograms_size)((distance_histograms_size) > 0 ? ((HistogramDistance*)BrotliAllocate
((m), (distance_histograms_size) * sizeof(HistogramDistance))
) : ((void*)0));
if (BROTLI_IS_OOM(m)(!!0) || BROTLI_IS_NULL(distance_histograms)(!!0)) return;
ClearHistogramsDistance(distance_histograms, distance_histograms_size);

BROTLI_DCHECK(mb->command_histograms == 0);
mb->command_histograms_size = mb->command_split.num_types;
mb->command_histograms =
    BROTLI_ALLOC(m, HistogramCommand, mb->command_histograms_size)((mb->command_histograms_size) > 0 ? ((HistogramCommand
*)BrotliAllocate((m), (mb->command_histograms_size) * sizeof
(HistogramCommand))) : ((void*)0));
if (BROTLI_IS_OOM(m)(!!0) || BROTLI_IS_NULL(mb->command_histograms)(!!0)) return;
ClearHistogramsCommand(mb->command_histograms, mb->command_histograms_size);

BrotliBuildHistogramsWithContext(cmds, num_commands,
    &mb->literal_split, &mb->command_split, &mb->distance_split,
    ringbuffer, pos, mask, prev_byte, prev_byte2, literal_context_modes,
    literal_histograms, mb->command_histograms, distance_histograms);
BROTLI_FREE(m, literal_context_modes){ BrotliFree((m), (literal_context_modes)); literal_context_modes
 = ((void*)0); };

BROTLI_DCHECK(mb->literal_context_map == 0);
mb->literal_context_map_size =
    mb->literal_split.num_types << BROTLI_LITERAL_CONTEXT_BITS6;
mb->literal_context_map =
    BROTLI_ALLOC(m, uint32_t, mb->literal_context_map_size)((mb->literal_context_map_size) > 0 ? ((uint32_t*)BrotliAllocate
((m), (mb->literal_context_map_size) * sizeof(uint32_t))) :
 ((void*)0));
if (BROTLI_IS_OOM(m)(!!0) || BROTLI_IS_NULL(mb->literal_context_map)(!!0)) return;

BROTLI_DCHECK(mb->literal_histograms == 0);
mb->literal_histograms_size = mb->literal_context_map_size;
mb->literal_histograms =
    BROTLI_ALLOC(m, HistogramLiteral, mb->literal_histograms_size)((mb->literal_histograms_size) > 0 ? ((HistogramLiteral
*)BrotliAllocate((m), (mb->literal_histograms_size) * sizeof
(HistogramLiteral))) : ((void*)0));
if (BROTLI_IS_OOM(m)(!!0) || BROTLI_IS_NULL(mb->literal_histograms)(!!0)) return;

BrotliClusterHistogramsLiteral(m, literal_histograms, literal_histograms_size,
    kMaxNumberOfHistograms, mb->literal_histograms,
    &mb->literal_histograms_size, mb->literal_context_map);
if (BROTLI_IS_OOM(m)(!!0)) return;
BROTLI_FREE(m, literal_histograms){ BrotliFree((m), (literal_histograms)); literal_histograms =
 ((void*)0); };

if (params->disable_literal_context_modeling) {
  /* Distribute assignment to all contexts. */
  for (i = mb->literal_split.num_types; i != 0;) {
    size_t j = 0;
    i--;
    for (; j < (1 << BROTLI_LITERAL_CONTEXT_BITS6); j++) {
      mb->literal_context_map[(i << BROTLI_LITERAL_CONTEXT_BITS6) + j] =
          mb->literal_context_map[i];
    }
  }
}

BROTLI_DCHECK(mb->distance_context_map == 0);
mb->distance_context_map_size =
    mb->distance_split.num_types << BROTLI_DISTANCE_CONTEXT_BITS2;
mb->distance_context_map =
    BROTLI_ALLOC(m, uint32_t, mb->distance_context_map_size)((mb->distance_context_map_size) > 0 ? ((uint32_t*)BrotliAllocate
((m), (mb->distance_context_map_size) * sizeof(uint32_t)))
 : ((void*)0));
if (BROTLI_IS_OOM(m)(!!0) || BROTLI_IS_NULL(mb->distance_context_map)(!!0)) return;

BROTLI_DCHECK(mb->distance_histograms == 0);
mb->distance_histograms_size = mb->distance_context_map_size;
mb->distance_histograms =
    BROTLI_ALLOC(m, HistogramDistance, mb->distance_histograms_size)((mb->distance_histograms_size) > 0 ? ((HistogramDistance
*)BrotliAllocate((m), (mb->distance_histograms_size) * sizeof
(HistogramDistance))) : ((void*)0));
if (BROTLI_IS_OOM(m)(!!0) || BROTLI_IS_NULL(mb->distance_histograms)(!!0)) return;

BrotliClusterHistogramsDistance(m, distance_histograms,
                                mb->distance_context_map_size,
                                kMaxNumberOfHistograms,
                                mb->distance_histograms,
                                &mb->distance_histograms_size,
                                mb->distance_context_map);
if (BROTLI_IS_OOM(m)(!!0)) return;
BROTLI_FREE(m, distance_histograms){ BrotliFree((m), (distance_histograms)); distance_histograms
 = ((void*)0); };
284}

286#define FN(X) X ## Literal
287#include "./metablock_inc.h"  /* NOLINT(build/include) */
288#undef FN

290#define FN(X) X ## Command
291#include "./metablock_inc.h"  /* NOLINT(build/include) */
292#undef FN

294#define FN(X) X ## Distance
295#include "./metablock_inc.h"  /* NOLINT(build/include) */
296#undef FN

298#define BROTLI_MAX_STATIC_CONTEXTS13 13

300/* Greedy block splitter for one block category (literal, command or distance).
 Gathers histograms for all context buckets. */
302typedef struct ContextBlockSplitter {
/* Alphabet size of particular block category. */
size_t alphabet_size_;
size_t num_contexts_;
size_t max_block_types_;
/* We collect at least this many symbols for each block. */
size_t min_block_size_;
/* We merge histograms A and B if
     entropy(A+B) < entropy(A) + entropy(B) + split_threshold_,
   where A is the current histogram and B is the histogram of the last or the
   second last block type. */
double split_threshold_;

size_t num_blocks_;
BlockSplit* split_;  /* not owned */
HistogramLiteral* histograms_;  /* not owned */
size_t* histograms_size_;  /* not owned */

/* The number of symbols that we want to collect before deciding on whether
   or not to merge the block with a previous one or emit a new block. */
size_t target_block_size_;
/* The number of symbols in the current histogram. */
size_t block_size_;
/* Offset of the current histogram. */
size_t curr_histogram_ix_;
/* Offset of the histograms of the previous two block types. */
size_t last_histogram_ix_[2];
/* Entropy of the previous two block types. */
double last_entropy_[2 * BROTLI_MAX_STATIC_CONTEXTS13];
/* The number of times we merged the current block with the last one. */
size_t merge_last_count_;
333} ContextBlockSplitter;

335static void InitContextBlockSplitter(
  MemoryManager* m, ContextBlockSplitter* self, size_t alphabet_size,
  size_t num_contexts, size_t min_block_size, double split_threshold,
  size_t num_symbols, BlockSplit* split, HistogramLiteral** histograms,
  size_t* histograms_size) {
size_t max_num_blocks = num_symbols / min_block_size + 1;
size_t max_num_types;
BROTLI_DCHECK(num_contexts <= BROTLI_MAX_STATIC_CONTEXTS);

self->alphabet_size_ = alphabet_size;
self->num_contexts_ = num_contexts;
self->max_block_types_ = BROTLI_MAX_NUMBER_OF_BLOCK_TYPES256 / num_contexts;
self->min_block_size_ = min_block_size;
self->split_threshold_ = split_threshold;
self->num_blocks_ = 0;
self->split_ = split;
self->histograms_size_ = histograms_size;
self->target_block_size_ = min_block_size;
self->block_size_ = 0;
self->curr_histogram_ix_ = 0;
self->merge_last_count_ = 0;

/* We have to allocate one more histogram than the maximum number of block
   types for the current histogram when the meta-block is too big. */
max_num_types =
    BROTLI_MIN(size_t, max_num_blocks, self->max_block_types_ + 1)(brotli_min_size_t((max_num_blocks), (self->max_block_types_
 + 1)));
BROTLI_ENSURE_CAPACITY(m, uint8_t,{ if (split->types_alloc_size < (max_num_blocks)) { size_t
 _new_size = (split->types_alloc_size == 0) ? (max_num_blocks
) : split->types_alloc_size; uint8_t* new_array; while (_new_size
 < (max_num_blocks)) _new_size *= 2; new_array = ((_new_size
) > 0 ? ((uint8_t*)BrotliAllocate(((m)), (_new_size) * sizeof
(uint8_t))) : ((void*)0)); if (!(!!0) && !(!!0) &&
 split->types_alloc_size != 0) memcpy(new_array, split->
types, split->types_alloc_size * sizeof(uint8_t)); { BrotliFree
(((m)), (split->types)); split->types = ((void*)0); }; split
->types = new_array; split->types_alloc_size = _new_size
; } }
    split->types, split->types_alloc_size, max_num_blocks){ if (split->types_alloc_size < (max_num_blocks)) { size_t
 _new_size = (split->types_alloc_size == 0) ? (max_num_blocks
) : split->types_alloc_size; uint8_t* new_array; while (_new_size
 < (max_num_blocks)) _new_size *= 2; new_array = ((_new_size
) > 0 ? ((uint8_t*)BrotliAllocate(((m)), (_new_size) * sizeof
(uint8_t))) : ((void*)0)); if (!(!!0) && !(!!0) &&
 split->types_alloc_size != 0) memcpy(new_array, split->
types, split->types_alloc_size * sizeof(uint8_t)); { BrotliFree
(((m)), (split->types)); split->types = ((void*)0); }; split
->types = new_array; split->types_alloc_size = _new_size
; } };
BROTLI_ENSURE_CAPACITY(m, uint32_t,{ if (split->lengths_alloc_size < (max_num_blocks)) { size_t
 _new_size = (split->lengths_alloc_size == 0) ? (max_num_blocks
) : split->lengths_alloc_size; uint32_t* new_array; while (
_new_size < (max_num_blocks)) _new_size *= 2; new_array = (
(_new_size) > 0 ? ((uint32_t*)BrotliAllocate(((m)), (_new_size
) * sizeof(uint32_t))) : ((void*)0)); if (!(!!0) && !
(!!0) && split->lengths_alloc_size != 0) memcpy(new_array
, split->lengths, split->lengths_alloc_size * sizeof(uint32_t
)); { BrotliFree(((m)), (split->lengths)); split->lengths
 = ((void*)0); }; split->lengths = new_array; split->lengths_alloc_size
 = _new_size; } }
    split->lengths, split->lengths_alloc_size, max_num_blocks){ if (split->lengths_alloc_size < (max_num_blocks)) { size_t
 _new_size = (split->lengths_alloc_size == 0) ? (max_num_blocks
) : split->lengths_alloc_size; uint32_t* new_array; while (
_new_size < (max_num_blocks)) _new_size *= 2; new_array = (
(_new_size) > 0 ? ((uint32_t*)BrotliAllocate(((m)), (_new_size
) * sizeof(uint32_t))) : ((void*)0)); if (!(!!0) && !
(!!0) && split->lengths_alloc_size != 0) memcpy(new_array
, split->lengths, split->lengths_alloc_size * sizeof(uint32_t
)); { BrotliFree(((m)), (split->lengths)); split->lengths
 = ((void*)0); }; split->lengths = new_array; split->lengths_alloc_size
 = _new_size; } };
if (BROTLI_IS_OOM(m)(!!0)) return;
split->num_blocks = max_num_blocks;
if (BROTLI_IS_OOM(m)(!!0)) return;
BROTLI_DCHECK(*histograms == 0);
*histograms_size = max_num_types * num_contexts;
*histograms = BROTLI_ALLOC(m, HistogramLiteral, *histograms_size)((*histograms_size) > 0 ? ((HistogramLiteral*)BrotliAllocate
((m), (*histograms_size) * sizeof(HistogramLiteral))) : ((void
*)0));
self->histograms_ = *histograms;
if (BROTLI_IS_OOM(m)(!!0) || BROTLI_IS_NULL(*histograms)(!!0)) return;
/* Clear only current histogram. */
ClearHistogramsLiteral(&self->histograms_[0], num_contexts);
self->last_histogram_ix_[0] = self->last_histogram_ix_[1] = 0;
376}

378/* Does either of three things:
   (1) emits the current block with a new block type;
   (2) emits the current block with the type of the second last block;
   (3) merges the current block with the last block. */
382static void ContextBlockSplitterFinishBlock(
  ContextBlockSplitter* self, MemoryManager* m, BROTLI_BOOLint is_final) {
BlockSplit* split = self->split_;
const size_t num_contexts = self->num_contexts_;
double* last_entropy = self->last_entropy_;
HistogramLiteral* histograms = self->histograms_;

if (self->block_size_ < self->min_block_size_) {
  self->block_size_ = self->min_block_size_;
}
if (self->num_blocks_ == 0) {
  size_t i;
  /* Create first block. */
  split->lengths[0] = (uint32_t)self->block_size_;
  split->types[0] = 0;

  for (i = 0; i < num_contexts; ++i) {
    last_entropy[i] =
        BitsEntropy(histograms[i].data_, self->alphabet_size_);
    last_entropy[num_contexts + i] = last_entropy[i];
  }
  ++self->num_blocks_;
  ++split->num_types;
  self->curr_histogram_ix_ += num_contexts;
  if (self->curr_histogram_ix_ < *self->histograms_size_) {
    ClearHistogramsLiteral(
        &self->histograms_[self->curr_histogram_ix_], self->num_contexts_);
  }
  self->block_size_ = 0;
} else if (self->block_size_ > 0) {
  /* Try merging the set of histograms for the current block type with the
     respective set of histograms for the last and second last block types.
     Decide over the split based on the total reduction of entropy across
     all contexts. */
  double entropy[BROTLI_MAX_STATIC_CONTEXTS13];
  HistogramLiteral* combined_histo =
      BROTLI_ALLOC(m, HistogramLiteral, 2 * num_contexts)((2 * num_contexts) > 0 ? ((HistogramLiteral*)BrotliAllocate
((m), (2 * num_contexts) * sizeof(HistogramLiteral))) : ((void
*)0));
  double combined_entropy[2 * BROTLI_MAX_STATIC_CONTEXTS13];
  double diff[2] = { 0.0 };
  size_t i;
  if (BROTLI_IS_OOM(m)(!!0) || BROTLI_IS_NULL(combined_histo)(!!0)) return;
  for (i = 0; i < num_contexts; ++i) {
    size_t curr_histo_ix = self->curr_histogram_ix_ + i;
    size_t j;
    entropy[i] = BitsEntropy(histograms[curr_histo_ix].data_,
                             self->alphabet_size_);
    for (j = 0; j < 2; ++j) {
      size_t jx = j * num_contexts + i;
      size_t last_histogram_ix = self->last_histogram_ix_[j] + i;
      combined_histo[jx] = histograms[curr_histo_ix];
      HistogramAddHistogramLiteral(&combined_histo[jx],
          &histograms[last_histogram_ix]);
      combined_entropy[jx] = BitsEntropy(
          &combined_histo[jx].data_[0], self->alphabet_size_);
      diff[j] += combined_entropy[jx] - entropy[i] - last_entropy[jx];
    }
  }

  if (split->num_types < self->max_block_types_ &&
      diff[0] > self->split_threshold_ &&
      diff[1] > self->split_threshold_) {
    /* Create new block. */
    split->lengths[self->num_blocks_] = (uint32_t)self->block_size_;
    split->types[self->num_blocks_] = (uint8_t)split->num_types;
    self->last_histogram_ix_[1] = self->last_histogram_ix_[0];
    self->last_histogram_ix_[0] = split->num_types * num_contexts;
    for (i = 0; i < num_contexts; ++i) {
      last_entropy[num_contexts + i] = last_entropy[i];
      last_entropy[i] = entropy[i];
    }
    ++self->num_blocks_;
    ++split->num_types;
    self->curr_histogram_ix_ += num_contexts;
    if (self->curr_histogram_ix_ < *self->histograms_size_) {
      ClearHistogramsLiteral(
          &self->histograms_[self->curr_histogram_ix_], self->num_contexts_);
    }
    self->block_size_ = 0;
    self->merge_last_count_ = 0;
    self->target_block_size_ = self->min_block_size_;
  } else if (diff[1] < diff[0] - 20.0) {
    /* Combine this block with second last block. */
    split->lengths[self->num_blocks_] = (uint32_t)self->block_size_;
    split->types[self->num_blocks_] = split->types[self->num_blocks_ - 2];
    BROTLI_SWAP(size_t, self->last_histogram_ix_, 0, 1){ size_t __brotli_swap_tmp = (self->last_histogram_ix_)[(0
)]; (self->last_histogram_ix_)[(0)] = (self->last_histogram_ix_
)[(1)]; (self->last_histogram_ix_)[(1)] = __brotli_swap_tmp
; };
    for (i = 0; i < num_contexts; ++i) {
      histograms[self->last_histogram_ix_[0] + i] =
          combined_histo[num_contexts + i];
      last_entropy[num_contexts + i] = last_entropy[i];
      last_entropy[i] = combined_entropy[num_contexts + i];
      HistogramClearLiteral(&histograms[self->curr_histogram_ix_ + i]);
    }
    ++self->num_blocks_;
    self->block_size_ = 0;
    self->merge_last_count_ = 0;
    self->target_block_size_ = self->min_block_size_;
  } else {
    /* Combine this block with last block. */
    split->lengths[self->num_blocks_ - 1] += (uint32_t)self->block_size_;
    for (i = 0; i < num_contexts; ++i) {
      histograms[self->last_histogram_ix_[0] + i] = combined_histo[i];
      last_entropy[i] = combined_entropy[i];
      if (split->num_types == 1) {
        last_entropy[num_contexts + i] = last_entropy[i];
      }
      HistogramClearLiteral(&histograms[self->curr_histogram_ix_ + i]);
    }
    self->block_size_ = 0;
    if (++self->merge_last_count_ > 1) {
      self->target_block_size_ += self->min_block_size_;
    }
  }
  BROTLI_FREE(m, combined_histo){ BrotliFree((m), (combined_histo)); combined_histo = ((void*
)0); };
}
if (is_final) {
  *self->histograms_size_ = split->num_types * num_contexts;
  split->num_blocks = self->num_blocks_;
}
500}

502/* Adds the next symbol to the current block type and context. When the
 current block reaches the target size, decides on merging the block. */
504static void ContextBlockSplitterAddSymbol(
  ContextBlockSplitter* self, MemoryManager* m,
  size_t symbol, size_t context) {
HistogramAddLiteral(&self->histograms_[self->curr_histogram_ix_ + context],
    symbol);
++self->block_size_;
if (self->block_size_ == self->target_block_size_) {
  ContextBlockSplitterFinishBlock(self, m, /* is_final = */ BROTLI_FALSE0);
  if (BROTLI_IS_OOM(m)(!!0)) return;
}
514}

516static void MapStaticContexts(MemoryManager* m,
                            size_t num_contexts,
                            const uint32_t* static_context_map,
                            MetaBlockSplit* mb) {
size_t i;
BROTLI_DCHECK(mb->literal_context_map == 0);
mb->literal_context_map_size =
    mb->literal_split.num_types << BROTLI_LITERAL_CONTEXT_BITS6;
mb->literal_context_map =
    BROTLI_ALLOC(m, uint32_t, mb->literal_context_map_size)((mb->literal_context_map_size) > 0 ? ((uint32_t*)BrotliAllocate
((m), (mb->literal_context_map_size) * sizeof(uint32_t))) :
 ((void*)0));
if (BROTLI_IS_OOM(m)(!!0) || BROTLI_IS_NULL(mb->literal_context_map)(!!0)) return;

for (i = 0; i < mb->literal_split.num_types; ++i) {
  uint32_t offset = (uint32_t)(i * num_contexts);
  size_t j;
  for (j = 0; j < (1u << BROTLI_LITERAL_CONTEXT_BITS6); ++j) {
    mb->literal_context_map[(i << BROTLI_LITERAL_CONTEXT_BITS6) + j] =
        offset + static_context_map[j];
  }
}
536}

538static BROTLI_INLINEinline __attribute__((__always_inline__)) void BrotliBuildMetaBlockGreedyInternal(
  MemoryManager* m, const uint8_t* ringbuffer, size_t pos, size_t mask,
  uint8_t prev_byte, uint8_t prev_byte2, ContextLut literal_context_lut,
  const size_t num_contexts, const uint32_t* static_context_map,
  const Command* commands, size_t n_commands, MetaBlockSplit* mb) {
union {
  BlockSplitterLiteral plain;
  ContextBlockSplitter ctx;
} lit_blocks;
BlockSplitterCommand cmd_blocks;
BlockSplitterDistance dist_blocks;
size_t num_literals = 0;
size_t i;
for (i = 0; i < n_commands; ++i) {
4
←
Assuming 'i' is < 'n_commands'→
5
←
Loop condition is true.  Entering loop body→
6
←
Assuming 'i' is >= 'n_commands'→
7
←
Loop condition is false. Execution continues on line 555→
  num_literals += commands[i].insert_len_;
}

if (num_contexts7.1
'num_contexts' is equal to 1
1
'num_contexts' is equal to 1
1
'num_contexts' is equal to 1
 == 1) {
8
←
Taking true branch→
  InitBlockSplitterLiteral(m, &lit_blocks.plain, 256, 512, 400.0,
9
←
Calling 'InitBlockSplitterLiteral'→
      num_literals, &mb->literal_split, &mb->literal_histograms,
      &mb->literal_histograms_size);
} else {
  InitContextBlockSplitter(m, &lit_blocks.ctx, 256, num_contexts, 512, 400.0,
      num_literals, &mb->literal_split, &mb->literal_histograms,
      &mb->literal_histograms_size);
}
if (BROTLI_IS_OOM(m)(!!0)) return;
InitBlockSplitterCommand(m, &cmd_blocks, BROTLI_NUM_COMMAND_SYMBOLS704, 1024,
    500.0, n_commands, &mb->command_split, &mb->command_histograms,
    &mb->command_histograms_size);
if (BROTLI_IS_OOM(m)(!!0)) return;
InitBlockSplitterDistance(m, &dist_blocks, 64, 512, 100.0, n_commands,
    &mb->distance_split, &mb->distance_histograms,
    &mb->distance_histograms_size);
if (BROTLI_IS_OOM(m)(!!0)) return;

for (i = 0; i < n_commands; ++i) {
  const Command cmd = commands[i];
  size_t j;
  BlockSplitterAddSymbolCommand(&cmd_blocks, cmd.cmd_prefix_);
  for (j = cmd.insert_len_; j != 0; --j) {
    uint8_t literal = ringbuffer[pos & mask];
    if (num_contexts == 1) {
      BlockSplitterAddSymbolLiteral(&lit_blocks.plain, literal);
    } else {
      size_t context =
          BROTLI_CONTEXT(prev_byte, prev_byte2, literal_context_lut)((literal_context_lut)[prev_byte] | ((literal_context_lut) + 256
)[prev_byte2]);
      ContextBlockSplitterAddSymbol(&lit_blocks.ctx, m, literal,
                                    static_context_map[context]);
      if (BROTLI_IS_OOM(m)(!!0)) return;
    }
    prev_byte2 = prev_byte;
    prev_byte = literal;
    ++pos;
  }
  pos += CommandCopyLen(&cmd);
  if (CommandCopyLen(&cmd)) {
    prev_byte2 = ringbuffer[(pos - 2) & mask];
    prev_byte = ringbuffer[(pos - 1) & mask];
    if (cmd.cmd_prefix_ >= 128) {
      BlockSplitterAddSymbolDistance(&dist_blocks, cmd.dist_prefix_ & 0x3FF);
    }
  }
}

if (num_contexts == 1) {
  BlockSplitterFinishBlockLiteral(
      &lit_blocks.plain, /* is_final = */ BROTLI_TRUE1);
} else {
  ContextBlockSplitterFinishBlock(
      &lit_blocks.ctx, m, /* is_final = */ BROTLI_TRUE1);
  if (BROTLI_IS_OOM(m)(!!0)) return;
}
BlockSplitterFinishBlockCommand(&cmd_blocks, /* is_final = */ BROTLI_TRUE1);
BlockSplitterFinishBlockDistance(&dist_blocks, /* is_final = */ BROTLI_TRUE1);

if (num_contexts > 1) {
  MapStaticContexts(m, num_contexts, static_context_map, mb);
}
617}

619void BrotliBuildMetaBlockGreedy(MemoryManager* m,
                              const uint8_t* ringbuffer,
                              size_t pos,
                              size_t mask,
                              uint8_t prev_byte,
                              uint8_t prev_byte2,
                              ContextLut literal_context_lut,
                              size_t num_contexts,
                              const uint32_t* static_context_map,
                              const Command* commands,
                              size_t n_commands,
                              MetaBlockSplit* mb) {
if (num_contexts == 1) {
1
Assuming 'num_contexts' is equal to 1→
2
←
Taking true branch→
  BrotliBuildMetaBlockGreedyInternal(m, ringbuffer, pos, mask, prev_byte,
3
←
Calling 'BrotliBuildMetaBlockGreedyInternal'→
      prev_byte2, literal_context_lut, 1, NULL((void*)0), commands, n_commands, mb);
} else {
  BrotliBuildMetaBlockGreedyInternal(m, ringbuffer, pos, mask, prev_byte,
      prev_byte2, literal_context_lut, num_contexts, static_context_map,
      commands, n_commands, mb);
}
639}

641void BrotliOptimizeHistograms(uint32_t num_distance_codes,
                            MetaBlockSplit* mb) {
uint8_t good_for_rle[BROTLI_NUM_COMMAND_SYMBOLS704];
size_t i;
for (i = 0; i < mb->literal_histograms_size; ++i) {
  BrotliOptimizeHuffmanCountsForRle(256, mb->literal_histograms[i].data_,
                                    good_for_rle);
}
for (i = 0; i < mb->command_histograms_size; ++i) {
  BrotliOptimizeHuffmanCountsForRle(BROTLI_NUM_COMMAND_SYMBOLS704,
                                    mb->command_histograms[i].data_,
                                    good_for_rle);
}
for (i = 0; i < mb->distance_histograms_size; ++i) {
  BrotliOptimizeHuffmanCountsForRle(num_distance_codes,
                                    mb->distance_histograms[i].data_,
                                    good_for_rle);
}
659}

661#if defined(__cplusplus) || defined(c_plusplus)
662}  /* extern "C" */
663#endif

←

../deps/brotli/c/enc/./metablock_inc.h

→

1/* NOLINT(build/header_guard) */
2/* Copyright 2015 Google Inc. All Rights Reserved.
3 
4   Distributed under MIT license.
5   See file LICENSE for detail or copy at https://opensource.org/licenses/MIT
6*/
7 
8/* template parameters: FN */
9 
10#define HistogramType FN(Histogram)
11 
12/* Greedy block splitter for one block category (literal, command or distance).
13*/
14typedef struct FN(BlockSplitter) {
15  /* Alphabet size of particular block category. */
16  size_t alphabet_size_;
17  /* We collect at least this many symbols for each block. */
18  size_t min_block_size_;
19  /* We merge histograms A and B if
20       entropy(A+B) < entropy(A) + entropy(B) + split_threshold_,
21     where A is the current histogram and B is the histogram of the last or the
22     second last block type. */
23  double split_threshold_;
24 
25  size_t num_blocks_;
26  BlockSplit* split_;  /* not owned */
27  HistogramType* histograms_;  /* not owned */
28  size_t* histograms_size_;  /* not owned */
29 
30  /* The number of symbols that we want to collect before deciding on whether
31     or not to merge the block with a previous one or emit a new block. */
32  size_t target_block_size_;
33  /* The number of symbols in the current histogram. */
34  size_t block_size_;
35  /* Offset of the current histogram. */
36  size_t curr_histogram_ix_;
37  /* Offset of the histograms of the previous two block types. */
38  size_t last_histogram_ix_[2];
39  /* Entropy of the previous two block types. */
40  double last_entropy_[2];
41  /* The number of times we merged the current block with the last one. */
42  size_t merge_last_count_;
43} FN(BlockSplitter);
44 
45static void FN(InitBlockSplitter)(
46    MemoryManager* m, FN(BlockSplitter)* self, size_t alphabet_size,
47    size_t min_block_size, double split_threshold, size_t num_symbols,
48    BlockSplit* split, HistogramType** histograms, size_t* histograms_size) {
49  size_t max_num_blocks = num_symbols / min_block_size + 1;
50  /* We have to allocate one more histogram than the maximum number of block
51     types for the current histogram when the meta-block is too big. */
52  size_t max_num_types =
53      BROTLI_MIN(size_t, max_num_blocks, BROTLI_MAX_NUMBER_OF_BLOCK_TYPES + 1)(brotli_min_size_t((max_num_blocks), (256 + 1)));
54  self->alphabet_size_ = alphabet_size;
55  self->min_block_size_ = min_block_size;
56  self->split_threshold_ = split_threshold;
57  self->num_blocks_ = 0;
58  self->split_ = split;
59  self->histograms_size_ = histograms_size;
60  self->target_block_size_ = min_block_size;
61  self->block_size_ = 0;
62  self->curr_histogram_ix_ = 0;
63  self->merge_last_count_ = 0;
64  BROTLI_ENSURE_CAPACITY(m, uint8_t,{ if (split->types_alloc_size < (max_num_blocks)) { size_t
 _new_size = (split->types_alloc_size == 0) ? (max_num_blocks
) : split->types_alloc_size; uint8_t* new_array; while (_new_size
 < (max_num_blocks)) _new_size *= 2; new_array = ((_new_size
) > 0 ? ((uint8_t*)BrotliAllocate(((m)), (_new_size) * sizeof
(uint8_t))) : ((void*)0)); if (!(!!0) && !(!!0) &&
 split->types_alloc_size != 0) memcpy(new_array, split->
types, split->types_alloc_size * sizeof(uint8_t)); { BrotliFree
(((m)), (split->types)); split->types = ((void*)0); }; split
->types = new_array; split->types_alloc_size = _new_size
; } }
10
←
Assuming 'max_num_blocks' is <= field 'types_alloc_size'→
11
←
Taking false branch→
65      split->types, split->types_alloc_size, max_num_blocks){ if (split->types_alloc_size < (max_num_blocks)) { size_t
 _new_size = (split->types_alloc_size == 0) ? (max_num_blocks
) : split->types_alloc_size; uint8_t* new_array; while (_new_size
 < (max_num_blocks)) _new_size *= 2; new_array = ((_new_size
) > 0 ? ((uint8_t*)BrotliAllocate(((m)), (_new_size) * sizeof
(uint8_t))) : ((void*)0)); if (!(!!0) && !(!!0) &&
 split->types_alloc_size != 0) memcpy(new_array, split->
types, split->types_alloc_size * sizeof(uint8_t)); { BrotliFree
(((m)), (split->types)); split->types = ((void*)0); }; split
->types = new_array; split->types_alloc_size = _new_size
; } };
66  BROTLI_ENSURE_CAPACITY(m, uint32_t,{ if (split->lengths_alloc_size < (max_num_blocks)) { size_t
 _new_size = (split->lengths_alloc_size == 0) ? (max_num_blocks
) : split->lengths_alloc_size; uint32_t* new_array; while (
_new_size < (max_num_blocks)) _new_size *= 2; new_array = (
(_new_size) > 0 ? ((uint32_t*)BrotliAllocate(((m)), (_new_size
) * sizeof(uint32_t))) : ((void*)0)); if (!(!!0) && !
(!!0) && split->lengths_alloc_size != 0) memcpy(new_array
, split->lengths, split->lengths_alloc_size * sizeof(uint32_t
)); { BrotliFree(((m)), (split->lengths)); split->lengths
 = ((void*)0); }; split->lengths = new_array; split->lengths_alloc_size
 = _new_size; } }
12
←
Assuming 'max_num_blocks' is <= field 'lengths_alloc_size'→
13
←
Taking false branch→
67      split->lengths, split->lengths_alloc_size, max_num_blocks){ if (split->lengths_alloc_size < (max_num_blocks)) { size_t
 _new_size = (split->lengths_alloc_size == 0) ? (max_num_blocks
) : split->lengths_alloc_size; uint32_t* new_array; while (
_new_size < (max_num_blocks)) _new_size *= 2; new_array = (
(_new_size) > 0 ? ((uint32_t*)BrotliAllocate(((m)), (_new_size
) * sizeof(uint32_t))) : ((void*)0)); if (!(!!0) && !
(!!0) && split->lengths_alloc_size != 0) memcpy(new_array
, split->lengths, split->lengths_alloc_size * sizeof(uint32_t
)); { BrotliFree(((m)), (split->lengths)); split->lengths
 = ((void*)0); }; split->lengths = new_array; split->lengths_alloc_size
 = _new_size; } };
68  if (BROTLI_IS_OOM(m)(!!0)) return;
14
←
Taking false branch→
69  self->split_->num_blocks = max_num_blocks;
70  BROTLI_DCHECK(*histograms == 0);
71  *histograms_size = max_num_types;
72  *histograms = BROTLI_ALLOC(m, HistogramType, *histograms_size)((*histograms_size) > 0 ? ((HistogramType*)BrotliAllocate(
(m), (*histograms_size) * sizeof(HistogramType))) : ((void*)0
));
15
←
Assuming the condition is false→
16
←
'?' condition is false→
73  self->histograms_ = *histograms;
74  if (BROTLI_IS_OOM(m)(!!0) || BROTLI_IS_NULL(*histograms)(!!0)) return;
17
←
Taking false branch→
75  /* Clear only current histogram. */
76  FN(HistogramClear)(&self->histograms_[0]);
18
←
Calling 'HistogramClearLiteral'→
77  self->last_histogram_ix_[0] = self->last_histogram_ix_[1] = 0;
78}
79 
80/* Does either of three things:
81     (1) emits the current block with a new block type;
82     (2) emits the current block with the type of the second last block;
83     (3) merges the current block with the last block. */
84static void FN(BlockSplitterFinishBlock)(
85    FN(BlockSplitter)* self, BROTLI_BOOLint is_final) {
86  BlockSplit* split = self->split_;
87  double* last_entropy = self->last_entropy_;
88  HistogramType* histograms = self->histograms_;
89  self->block_size_ =
90      BROTLI_MAX(size_t, self->block_size_, self->min_block_size_)(brotli_max_size_t((self->block_size_), (self->min_block_size_
)));
91  if (self->num_blocks_ == 0) {
92    /* Create first block. */
93    split->lengths[0] = (uint32_t)self->block_size_;
94    split->types[0] = 0;
95    last_entropy[0] =
96        BitsEntropy(histograms[0].data_, self->alphabet_size_);
97    last_entropy[1] = last_entropy[0];
98    ++self->num_blocks_;
99    ++split->num_types;
100    ++self->curr_histogram_ix_;
101    if (self->curr_histogram_ix_ < *self->histograms_size_)
102      FN(HistogramClear)(&histograms[self->curr_histogram_ix_]);
103    self->block_size_ = 0;
104  } else if (self->block_size_ > 0) {
105    double entropy = BitsEntropy(histograms[self->curr_histogram_ix_].data_,
106                                 self->alphabet_size_);
107    HistogramType combined_histo[2];
108    double combined_entropy[2];
109    double diff[2];
110    size_t j;
111    for (j = 0; j < 2; ++j) {
112      size_t last_histogram_ix = self->last_histogram_ix_[j];
113      combined_histo[j] = histograms[self->curr_histogram_ix_];
114      FN(HistogramAddHistogram)(&combined_histo[j],
115          &histograms[last_histogram_ix]);
116      combined_entropy[j] = BitsEntropy(
117          &combined_histo[j].data_[0], self->alphabet_size_);
118      diff[j] = combined_entropy[j] - entropy - last_entropy[j];
119    }
120 
121    if (split->num_types < BROTLI_MAX_NUMBER_OF_BLOCK_TYPES256 &&
122        diff[0] > self->split_threshold_ &&
123        diff[1] > self->split_threshold_) {
124      /* Create new block. */
125      split->lengths[self->num_blocks_] = (uint32_t)self->block_size_;
126      split->types[self->num_blocks_] = (uint8_t)split->num_types;
127      self->last_histogram_ix_[1] = self->last_histogram_ix_[0];
128      self->last_histogram_ix_[0] = (uint8_t)split->num_types;
129      last_entropy[1] = last_entropy[0];
130      last_entropy[0] = entropy;
131      ++self->num_blocks_;
132      ++split->num_types;
133      ++self->curr_histogram_ix_;
134      if (self->curr_histogram_ix_ < *self->histograms_size_)
135        FN(HistogramClear)(&histograms[self->curr_histogram_ix_]);
136      self->block_size_ = 0;
137      self->merge_last_count_ = 0;
138      self->target_block_size_ = self->min_block_size_;
139    } else if (diff[1] < diff[0] - 20.0) {
140      /* Combine this block with second last block. */
141      split->lengths[self->num_blocks_] = (uint32_t)self->block_size_;
142      split->types[self->num_blocks_] = split->types[self->num_blocks_ - 2];
143      BROTLI_SWAP(size_t, self->last_histogram_ix_, 0, 1){ size_t __brotli_swap_tmp = (self->last_histogram_ix_)[(0
)]; (self->last_histogram_ix_)[(0)] = (self->last_histogram_ix_
)[(1)]; (self->last_histogram_ix_)[(1)] = __brotli_swap_tmp
; };
144      histograms[self->last_histogram_ix_[0]] = combined_histo[1];
145      last_entropy[1] = last_entropy[0];
146      last_entropy[0] = combined_entropy[1];
147      ++self->num_blocks_;
148      self->block_size_ = 0;
149      FN(HistogramClear)(&histograms[self->curr_histogram_ix_]);
150      self->merge_last_count_ = 0;
151      self->target_block_size_ = self->min_block_size_;
152    } else {
153      /* Combine this block with last block. */
154      split->lengths[self->num_blocks_ - 1] += (uint32_t)self->block_size_;
155      histograms[self->last_histogram_ix_[0]] = combined_histo[0];
156      last_entropy[0] = combined_entropy[0];
157      if (split->num_types == 1) {
158        last_entropy[1] = last_entropy[0];
159      }
160      self->block_size_ = 0;
161      FN(HistogramClear)(&histograms[self->curr_histogram_ix_]);
162      if (++self->merge_last_count_ > 1) {
163        self->target_block_size_ += self->min_block_size_;
164      }
165    }
166  }
167  if (is_final) {
168    *self->histograms_size_ = split->num_types;
169    split->num_blocks = self->num_blocks_;
170  }
171}
172 
173/* Adds the next symbol to the current histogram. When the current histogram
174   reaches the target size, decides on merging the block. */
175static void FN(BlockSplitterAddSymbol)(FN(BlockSplitter)* self, size_t symbol) {
176  FN(HistogramAdd)(&self->histograms_[self->curr_histogram_ix_], symbol);
177  ++self->block_size_;
178  if (self->block_size_ == self->target_block_size_) {
179    FN(BlockSplitterFinishBlock)(self, /* is_final = */ BROTLI_FALSE0);
180  }
181}
182 
183#undef HistogramType

←

../deps/brotli/c/enc/./histogram_inc.h

1/* NOLINT(build/header_guard) */
2/* Copyright 2013 Google Inc. All Rights Reserved.
3 
4   Distributed under MIT license.
5   See file LICENSE for detail or copy at https://opensource.org/licenses/MIT
6*/
7 
8/* template parameters: Histogram, DATA_SIZE, DataType */
9 
10/* A simple container for histograms of data in blocks. */
11 
12typedef struct FN(Histogram) {
13  uint32_t data_[DATA_SIZE];
14  size_t total_count_;
15  double bit_cost_;
16} FN(Histogram);
17 
18static BROTLI_INLINEinline __attribute__((__always_inline__)) void FN(HistogramClear)(FN(Histogram)* self) {
19  memset(self->data_, 0, sizeof(self->data_));
19
←
Null pointer passed to 1st parameter expecting 'nonnull'
20  self->total_count_ = 0;
21  self->bit_cost_ = HUGE_VAL(__builtin_huge_val ());
22}
23 
24static BROTLI_INLINEinline __attribute__((__always_inline__)) void FN(ClearHistograms)(
25    FN(Histogram)* array, size_t length) {
26  size_t i;
27  for (i = 0; i < length; ++i) FN(HistogramClear)(array + i);
28}
29 
30static BROTLI_INLINEinline __attribute__((__always_inline__)) void FN(HistogramAdd)(FN(Histogram)* self, size_t val) {
31  ++self->data_[val];
32  ++self->total_count_;
33}
34 
35static BROTLI_INLINEinline __attribute__((__always_inline__)) void FN(HistogramAddVector)(FN(Histogram)* self,
36    const DataType* p, size_t n) {
37  self->total_count_ += n;
38  n += 1;
39  while (--n) ++self->data_[*p++];
40}
41 
42static BROTLI_INLINEinline __attribute__((__always_inline__)) void FN(HistogramAddHistogram)(FN(Histogram)* self,
43    const FN(Histogram)* v) {
44  size_t i;
45  self->total_count_ += v->total_count_;
46  for (i = 0; i < DATA_SIZE; ++i) {
47    self->data_[i] += v->data_[i];
48  }
49}
50 
51static BROTLI_INLINEinline __attribute__((__always_inline__)) size_t FN(HistogramDataSize)(void) { return DATA_SIZE; }