BaseTools: Copy Brotli algorithm 3rd party source code for tool

[mirror_edk2.git] / BaseTools / Source / C / BrotliCompress / enc / histogram.c

/* Copyright 2013 Google Inc. All Rights Reserved.\r
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   Distributed under MIT license.\r
   See file LICENSE for detail or copy at https://opensource.org/licenses/MIT\r
*/\r
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/* Build per-context histograms of literals, commands and distance codes. */\r
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#include "./histogram.h"\r
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#include "./block_splitter.h"\r
#include "./command.h"\r
#include "./context.h"\r
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#if defined(__cplusplus) || defined(c_plusplus)\r
extern "C" {\r
#endif\r
\r
typedef struct BlockSplitIterator {\r
  const BlockSplit* split_;  /* Not owned. */\r
  size_t idx_;\r
  size_t type_;\r
  size_t length_;\r
} BlockSplitIterator;\r
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static void InitBlockSplitIterator(BlockSplitIterator* self,\r
    const BlockSplit* split) {\r
  self->split_ = split;\r
  self->idx_ = 0;\r
  self->type_ = 0;\r
  self->length_ = split->lengths ? split->lengths[0] : 0;\r
}\r
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static void BlockSplitIteratorNext(BlockSplitIterator* self) {\r
  if (self->length_ == 0) {\r
    ++self->idx_;\r
    self->type_ = self->split_->types[self->idx_];\r
    self->length_ = self->split_->lengths[self->idx_];\r
  }\r
  --self->length_;\r
}\r
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void BrotliBuildHistogramsWithContext(\r
    const Command* cmds, const size_t num_commands,\r
    const BlockSplit* literal_split, const BlockSplit* insert_and_copy_split,\r
    const BlockSplit* dist_split, const uint8_t* ringbuffer, size_t start_pos,\r
    size_t mask, uint8_t prev_byte, uint8_t prev_byte2,\r
    const ContextType* context_modes, HistogramLiteral* literal_histograms,\r
    HistogramCommand* insert_and_copy_histograms,\r
    HistogramDistance* copy_dist_histograms) {\r
  size_t pos = start_pos;\r
  BlockSplitIterator literal_it;\r
  BlockSplitIterator insert_and_copy_it;\r
  BlockSplitIterator dist_it;\r
  size_t i;\r
\r
  InitBlockSplitIterator(&literal_it, literal_split);\r
  InitBlockSplitIterator(&insert_and_copy_it, insert_and_copy_split);\r
  InitBlockSplitIterator(&dist_it, dist_split);\r
  for (i = 0; i < num_commands; ++i) {\r
    const Command* cmd = &cmds[i];\r
    size_t j;\r
    BlockSplitIteratorNext(&insert_and_copy_it);\r
    HistogramAddCommand(&insert_and_copy_histograms[insert_and_copy_it.type_],\r
        cmd->cmd_prefix_);\r
    for (j = cmd->insert_len_; j != 0; --j) {\r
      size_t context;\r
      BlockSplitIteratorNext(&literal_it);\r
      context = (literal_it.type_ << BROTLI_LITERAL_CONTEXT_BITS) +\r
          Context(prev_byte, prev_byte2, context_modes[literal_it.type_]);\r
      HistogramAddLiteral(&literal_histograms[context],\r
          ringbuffer[pos & mask]);\r
      prev_byte2 = prev_byte;\r
      prev_byte = ringbuffer[pos & mask];\r
      ++pos;\r
    }\r
    pos += CommandCopyLen(cmd);\r
    if (CommandCopyLen(cmd)) {\r
      prev_byte2 = ringbuffer[(pos - 2) & mask];\r
      prev_byte = ringbuffer[(pos - 1) & mask];\r
      if (cmd->cmd_prefix_ >= 128) {\r
        size_t context;\r
        BlockSplitIteratorNext(&dist_it);\r
        context = (dist_it.type_ << BROTLI_DISTANCE_CONTEXT_BITS) +\r
            CommandDistanceContext(cmd);\r
        HistogramAddDistance(&copy_dist_histograms[context],\r
            cmd->dist_prefix_);\r
      }\r
    }\r
  }\r
}\r
\r
#if defined(__cplusplus) || defined(c_plusplus)\r
}  /* extern "C" */\r
#endif\r