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df4f93e79f
Built to libwebp code in to support the static option of webp loader. Code from :https://github.com/jacklicn/libwebp This forking version only contains the minimal webp decoding feature. Binary Size: +68kb Co-authored-by: Hermet Park <hermet@lottiefiles.com> issue: https://github.com/thorvg/thorvg/issues/1427
67 lines
2.3 KiB
C
67 lines
2.3 KiB
C
// Copyright 2012 Google Inc. All Rights Reserved.
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//
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// Use of this source code is governed by a BSD-style license
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// that can be found in the COPYING file in the root of the source
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// tree. An additional intellectual property rights grant can be found
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// in the file PATENTS. All contributing project authors may
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// be found in the AUTHORS file in the root of the source tree.
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// -----------------------------------------------------------------------------
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//
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// Utilities for building and looking up Huffman trees.
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//
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// Author: Urvang Joshi (urvang@google.com)
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#ifndef WEBP_UTILS_HUFFMAN_H_
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#define WEBP_UTILS_HUFFMAN_H_
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#include <assert.h>
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#include "../webp/format_constants.h"
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#include "../webp/types.h"
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#ifdef __cplusplus
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extern "C" {
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#endif
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#define HUFFMAN_TABLE_BITS 8
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#define HUFFMAN_TABLE_MASK ((1 << HUFFMAN_TABLE_BITS) - 1)
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#define LENGTHS_TABLE_BITS 7
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#define LENGTHS_TABLE_MASK ((1 << LENGTHS_TABLE_BITS) - 1)
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// Huffman lookup table entry
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typedef struct {
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uint8_t bits; // number of bits used for this symbol
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uint16_t value; // symbol value or table offset
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} HuffmanCode;
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// Huffman table group.
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typedef struct HTreeGroup HTreeGroup;
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struct HTreeGroup {
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HuffmanCode* htrees[HUFFMAN_CODES_PER_META_CODE];
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int is_trivial_literal; // True, if huffman trees for Red, Blue & Alpha
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// Symbols are trivial (have a single code).
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uint32_t literal_arb; // If is_trivial_literal is true, this is the
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// ARGB value of the pixel, with Green channel
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// being set to zero.
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};
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// Creates the instance of HTreeGroup with specified number of tree-groups.
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HTreeGroup* VP8LHtreeGroupsNew(int num_htree_groups);
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// Releases the memory allocated for HTreeGroup.
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void VP8LHtreeGroupsFree(HTreeGroup* const htree_groups);
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// Builds Huffman lookup table assuming code lengths are in symbol order.
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// The 'code_lengths' is pre-allocated temporary memory buffer used for creating
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// the huffman table.
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// Returns built table size or 0 in case of error (invalid tree or
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// memory error).
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int VP8LBuildHuffmanTable(HuffmanCode* const root_table, int root_bits,
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const int code_lengths[], int code_lengths_size);
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#ifdef __cplusplus
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} // extern "C"
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#endif
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#endif // WEBP_UTILS_HUFFMAN_H_
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