libwebp: update to 0.5.0

third_party/libwebp/utils/huffman_encode.h

 // 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)
@@ skipping 16 matching lines @@
 } 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.
-// TODO(vikasa): Add comment for the fields of the Struct.
 typedef struct {
-  uint32_t total_count_;
-  int value_;
+  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_