mirror of
https://github.com/google/brotli.git
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a8f5813b84
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)
73 lines
2.8 KiB
C
73 lines
2.8 KiB
C
/* Copyright 2015 Google Inc. All Rights Reserved.
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Distributed under MIT license.
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See file LICENSE for detail or copy at https://opensource.org/licenses/MIT
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*/
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/* Function for fast encoding of an input fragment, independently from the input
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history. This function uses two-pass processing: in the first pass we save
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the found backward matches and literal bytes into a buffer, and in the
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second pass we emit them into the bit stream using prefix codes built based
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on the actual command and literal byte histograms. */
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#ifndef BROTLI_ENC_COMPRESS_FRAGMENT_TWO_PASS_H_
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#define BROTLI_ENC_COMPRESS_FRAGMENT_TWO_PASS_H_
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#include <brotli/types.h>
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#include "../common/constants.h"
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#include "../common/platform.h"
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#include "entropy_encode.h"
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#if defined(__cplusplus) || defined(c_plusplus)
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extern "C" {
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#endif
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/* TODO(eustas): turn to macro. */
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static const size_t kCompressFragmentTwoPassBlockSize = 1 << 17;
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typedef struct BrotliTwoPassArena {
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uint32_t lit_histo[256];
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uint8_t lit_depth[256];
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uint16_t lit_bits[256];
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uint32_t cmd_histo[128];
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uint8_t cmd_depth[128];
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uint16_t cmd_bits[128];
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/* BuildAndStoreCommandPrefixCode */
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HuffmanTree tmp_tree[2 * BROTLI_NUM_LITERAL_SYMBOLS + 1];
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uint8_t tmp_depth[BROTLI_NUM_COMMAND_SYMBOLS];
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uint16_t tmp_bits[64];
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} BrotliTwoPassArena;
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/* Compresses "input" string to the "*storage" buffer as one or more complete
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meta-blocks, and updates the "*storage_ix" bit position.
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If "is_last" is 1, emits an additional empty last meta-block.
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REQUIRES: "input_size" is greater than zero, or "is_last" is 1.
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REQUIRES: "input_size" is less or equal to maximal metablock size (1 << 24).
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REQUIRES: "command_buf" and "literal_buf" point to at least
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kCompressFragmentTwoPassBlockSize long arrays.
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REQUIRES: All elements in "table[0..table_size-1]" are initialized to zero.
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REQUIRES: "table_size" is a power of two
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OUTPUT: maximal copy distance <= |input_size|
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OUTPUT: maximal copy distance <= BROTLI_MAX_BACKWARD_LIMIT(18) */
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BROTLI_INTERNAL void BrotliCompressFragmentTwoPass(BrotliTwoPassArena* s,
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const uint8_t* input,
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size_t input_size,
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BROTLI_BOOL is_last,
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uint32_t* command_buf,
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uint8_t* literal_buf,
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int* table,
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size_t table_size,
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size_t* storage_ix,
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uint8_t* storage);
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#if defined(__cplusplus) || defined(c_plusplus)
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} /* extern "C" */
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#endif
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#endif /* BROTLI_ENC_COMPRESS_FRAGMENT_TWO_PASS_H_ */
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