From 2c1f833a092ef7af17f072749940bcb47da19aa6 Mon Sep 17 00:00:00 2001 From: wolfbeast Date: Mon, 24 Jul 2017 13:19:25 +0200 Subject: Add libwebp 0.6.0 to the tree --- media/libwebp/utils/huffman_encode_utils.h | 60 ++++++++++++++++++++++++++++++ 1 file changed, 60 insertions(+) create mode 100644 media/libwebp/utils/huffman_encode_utils.h (limited to 'media/libwebp/utils/huffman_encode_utils.h') diff --git a/media/libwebp/utils/huffman_encode_utils.h b/media/libwebp/utils/huffman_encode_utils.h new file mode 100644 index 000000000..a15716514 --- /dev/null +++ b/media/libwebp/utils/huffman_encode_utils.h @@ -0,0 +1,60 @@ +// 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; + +// Struct to represent the Huffman tree. +typedef struct { + uint32_t total_count_; // Symbol frequency. + int value_; // Symbol value. + int pool_index_left_; // Index for the left sub-tree. + int pool_index_right_; // Index for the right sub-tree. +} HuffmanTree; + +// 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. +// 'buf_rle' and 'huff_tree' are pre-allocated and the 'tree' is the constructed +// huffman code tree. +void VP8LCreateHuffmanTree(uint32_t* const histogram, int tree_depth_limit, + uint8_t* const buf_rle, HuffmanTree* const huff_tree, + HuffmanTreeCode* const tree); + +#ifdef __cplusplus +} +#endif + +#endif // WEBP_UTILS_HUFFMAN_ENCODE_H_ -- cgit v1.2.3