libwebp: update snapshot to v0.2.0-rc1

third_party/libwebp/utils/huffman_encode.h

+// Copyright 2011 Google Inc. All Rights Reserved.
+//
+// This code is licensed under the same terms as WebM:
+//  Software License Agreement:  http://www.webmproject.org/license/software/
+//  Additional IP Rights Grant:  http://www.webmproject.org/license/additional/
+// -----------------------------------------------------------------------------
+//
+// 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"
+
+#if defined(__cplusplus) || defined(c_plusplus)
+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);
+
+#if defined(__cplusplus) || defined(c_plusplus)
+}
+#endif
+
+#endif  // WEBP_UTILS_HUFFMAN_ENCODE_H_