kc3-lang/brotli/c/enc/compress_fragment_two_pass.h

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• Hash : a8f5813b
  Author :
  Date : 2022-11-17T13:03:09
  

  Update
  
  Documentation:
    - add note that brotli is a "stream" format, not an archive-like
    - regenerate .1 with Pandoc
  Build:
    - drop legacy "BROTLI_BUILD_PORTABLE" option
    - drop "BROTLI_SANITIZED" definition
  Code:
    - c: comb includes
    - c/enc: extract encoder state into separate header
    - c/enc: drop designated q10 codepath
    - c/enc: dealing better with flushing of empty stream
    - fix MSVC compilation
  API:
    - py: use library version instead of one in version.h
    - c: add plugable API to report consumed input / produced output
    - c/java: support "lean" prepared dictionaries (without copy of source)
  

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• c/enc/compress_fragment_two_pass.h

• /* Copyright 2015 Google Inc. All Rights Reserved.
  
     Distributed under MIT license.
     See file LICENSE for detail or copy at https://opensource.org/licenses/MIT
  */
  
  /* Function for fast encoding of an input fragment, independently from the input
     history. This function uses two-pass processing: in the first pass we save
     the found backward matches and literal bytes into a buffer, and in the
     second pass we emit them into the bit stream using prefix codes built based
     on the actual command and literal byte histograms. */
  
  #ifndef BROTLI_ENC_COMPRESS_FRAGMENT_TWO_PASS_H_
  #define BROTLI_ENC_COMPRESS_FRAGMENT_TWO_PASS_H_
  
  #include <brotli/types.h>
  
  #include "../common/constants.h"
  #include "../common/platform.h"
  #include "entropy_encode.h"
  
  #if defined(__cplusplus) || defined(c_plusplus)
  extern "C" {
  #endif
  
  /* TODO(eustas): turn to macro. */
  static const size_t kCompressFragmentTwoPassBlockSize = 1 << 17;
  
  typedef struct BrotliTwoPassArena {
    uint32_t lit_histo[256];
    uint8_t lit_depth[256];
    uint16_t lit_bits[256];
  
    uint32_t cmd_histo[128];
    uint8_t cmd_depth[128];
    uint16_t cmd_bits[128];
  
    /* BuildAndStoreCommandPrefixCode */
    HuffmanTree tmp_tree[2 * BROTLI_NUM_LITERAL_SYMBOLS + 1];
    uint8_t tmp_depth[BROTLI_NUM_COMMAND_SYMBOLS];
    uint16_t tmp_bits[64];
  } BrotliTwoPassArena;
  
  /* Compresses "input" string to the "*storage" buffer as one or more complete
     meta-blocks, and updates the "*storage_ix" bit position.
  
     If "is_last" is 1, emits an additional empty last meta-block.
  
     REQUIRES: "input_size" is greater than zero, or "is_last" is 1.
     REQUIRES: "input_size" is less or equal to maximal metablock size (1 << 24).
     REQUIRES: "command_buf" and "literal_buf" point to at least
                kCompressFragmentTwoPassBlockSize long arrays.
     REQUIRES: All elements in "table[0..table_size-1]" are initialized to zero.
     REQUIRES: "table_size" is a power of two
     OUTPUT: maximal copy distance <= |input_size|
     OUTPUT: maximal copy distance <= BROTLI_MAX_BACKWARD_LIMIT(18) */
  BROTLI_INTERNAL void BrotliCompressFragmentTwoPass(BrotliTwoPassArena* s,
                                                     const uint8_t* input,
                                                     size_t input_size,
                                                     BROTLI_BOOL is_last,
                                                     uint32_t* command_buf,
                                                     uint8_t* literal_buf,
                                                     int* table,
                                                     size_t table_size,
                                                     size_t* storage_ix,
                                                     uint8_t* storage);
  
  #if defined(__cplusplus) || defined(c_plusplus)
  }  /* extern "C" */
  #endif
  
  #endif  /* BROTLI_ENC_COMPRESS_FRAGMENT_TWO_PASS_H_ */
  

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