Update libwebp to 0.4.0

third_party/libwebp/utils/huffman_encode.c

 // 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.
 
 #include <assert.h>
 #include <stdlib.h>
 #include <string.h>
 #include "./huffman_encode.h"
 #include "../utils/utils.h"
 #include "../webp/format_constants.h"
 
 // -----------------------------------------------------------------------------
 // Util function to optimize the symbol map for RLE coding
 
 // Heuristics for selecting the stride ranges to collapse.
 static int ValuesShouldBeCollapsedToStrideAverage(int a, int b) {
   return abs(a - b) < 4;
 }
 
 // Change the population counts in a way that the consequent
-// Hufmann tree compression, especially its RLE-part, give smaller output.
+// Huffman tree compression, especially its RLE-part, give smaller output.
 static int OptimizeHuffmanForRle(int length, int* const counts) {
   uint8_t* good_for_rle;
   // 1) Let's make the Huffman code more compatible with rle encoding.
   int i;
   for (; length >= 0; --length) {
     if (length == 0) {
       return 1;  // All zeros.
     }
     if (counts[length - 1] != 0) {
       // Now counts[0..length - 1] does not have trailing zeros.
@@ skipping 390 matching lines @@
     return 0;
   }
   if (!GenerateOptimalTree(histogram, num_symbols,
                            tree_depth_limit, tree->code_lengths)) {
     return 0;
   }
   // Create the actual bit codes for the bit lengths.
   ConvertBitDepthsToSymbols(tree);
   return 1;
 }