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Diffstat (limited to 'src/3rdparty/libwebp/src/utils/huffman_encode.h')
| -rw-r--r-- | src/3rdparty/libwebp/src/utils/huffman_encode.h | 49 |
1 files changed, 49 insertions, 0 deletions
diff --git a/src/3rdparty/libwebp/src/utils/huffman_encode.h b/src/3rdparty/libwebp/src/utils/huffman_encode.h new file mode 100644 index 0000000..ee51c68 --- /dev/null +++ b/src/3rdparty/libwebp/src/utils/huffman_encode.h @@ -0,0 +1,49 @@ +// Copyright 2011 Google Inc. All Rights Reserved. +// +// Use of this source code is governed by a BSD-style license +// that can be found in the COPYING file in the root of the source +// tree. An additional intellectual property rights grant can be found +// in the file PATENTS. All contributing project authors may +// be found in the AUTHORS file in the root of the source tree. +// ----------------------------------------------------------------------------- +// +// Author: Jyrki Alakuijala (jyrki@google.com) +// +// Entropy encoding (Huffman) for webp lossless + +#ifndef WEBP_UTILS_HUFFMAN_ENCODE_H_ +#define WEBP_UTILS_HUFFMAN_ENCODE_H_ + +#include "../webp/types.h" + +#ifdef __cplusplus +extern "C" { +#endif + +// Struct for holding the tree header in coded form. +typedef struct { + uint8_t code; // value (0..15) or escape code (16,17,18) + uint8_t extra_bits; // extra bits for escape codes +} HuffmanTreeToken; + +// Struct to represent the tree codes (depth and bits array). +typedef struct { + int num_symbols; // Number of symbols. + uint8_t* code_lengths; // Code lengths of the symbols. + uint16_t* codes; // Symbol Codes. +} HuffmanTreeCode; + +// Turn the Huffman tree into a token sequence. +// Returns the number of tokens used. +int VP8LCreateCompressedHuffmanTree(const HuffmanTreeCode* const tree, + HuffmanTreeToken* tokens, int max_tokens); + +// Create an optimized tree, and tokenize it. +int VP8LCreateHuffmanTree(int* const histogram, int tree_depth_limit, + HuffmanTreeCode* const tree); + +#ifdef __cplusplus +} +#endif + +#endif // WEBP_UTILS_HUFFMAN_ENCODE_H_ |