Update libwebp to 0.4.0

third_party/libwebp/utils/huffman.h

 // Copyright 2012 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.
 // -----------------------------------------------------------------------------
 //
 // Utilities for building and looking up Huffman trees.
 //
 // Author: Urvang Joshi (urvang@google.com)
 
 #ifndef WEBP_UTILS_HUFFMAN_H_
 #define WEBP_UTILS_HUFFMAN_H_
 
 #include <assert.h>
 #include "../webp/types.h"
 
-#if defined(__cplusplus) || defined(c_plusplus)
+#ifdef __cplusplus
 extern "C" {
 #endif
 
 // A node of a Huffman tree.
 typedef struct {
   int symbol_;
   int children_;  // delta offset to both children (contiguous) or 0 if leaf.
 } HuffmanTreeNode;
 
 // Huffman Tree.
+#define HUFF_LUT_BITS 7
+#define HUFF_LUT (1U << HUFF_LUT_BITS)
 typedef struct HuffmanTree HuffmanTree;
 struct HuffmanTree {
+  // Fast lookup for short bit lengths.
+  uint8_t lut_bits_[HUFF_LUT];
+  int16_t lut_symbol_[HUFF_LUT];
+  int16_t lut_jump_[HUFF_LUT];
+  // Complete tree for lookups.
   HuffmanTreeNode* root_;   // all the nodes, starting at root.
   int max_nodes_;           // max number of nodes
   int num_nodes_;           // number of currently occupied nodes
 };
 
-// Returns true if the given node is a leaf of the Huffman tree.
-static WEBP_INLINE int HuffmanTreeNodeIsLeaf(
+// Returns true if the given node is not a leaf of the Huffman tree.
+static WEBP_INLINE int HuffmanTreeNodeIsNotLeaf(
     const HuffmanTreeNode* const node) {
-  return (node->children_ == 0);
+  return node->children_;
 }
 
 // Go down one level. Most critical function. 'right_child' must be 0 or 1.
 static WEBP_INLINE const HuffmanTreeNode* HuffmanTreeNextNode(
     const HuffmanTreeNode* node, int right_child) {
   return node + node->children_ + right_child;
 }
 
 // Releases the nodes of the Huffman tree.
 // Note: It does NOT free 'tree' itself.
@@ skipping 14 matching lines @@
                              const int* const symbols, int max_symbol,
                              int num_symbols);
 
 // Utility: converts Huffman code lengths to corresponding Huffman codes.
 // 'huff_codes' should be pre-allocated.
 // Returns false in case of error (memory allocation, invalid codes).
 int HuffmanCodeLengthsToCodes(const int* const code_lengths,
                               int code_lengths_size, int* const huff_codes);
 
 
-#if defined(__cplusplus) || defined(c_plusplus)
+#ifdef __cplusplus
 }    // extern "C"
 #endif
 
 #endif  // WEBP_UTILS_HUFFMAN_H_