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diff --git a/src/main/jni/libwebp/utils/huffman.c b/src/main/jni/libwebp/utils/huffman.c
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+// 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)
+
+#include <assert.h>
+#include <stdlib.h>
+#include <string.h>
+#include "./huffman.h"
+#include "../utils/utils.h"
+#include "../webp/format_constants.h"
+
+// Uncomment the following to use look-up table for ReverseBits()
+// (might be faster on some platform)
+// #define USE_LUT_REVERSE_BITS
+
+// Huffman data read via DecodeImageStream is represented in two (red and green)
+// bytes.
+#define MAX_HTREE_GROUPS 0x10000
+#define NON_EXISTENT_SYMBOL (-1)
+
+static void TreeNodeInit(HuffmanTreeNode* const node) {
+ node->children_ = -1; // means: 'unassigned so far'
+}
+
+static int NodeIsEmpty(const HuffmanTreeNode* const node) {
+ return (node->children_ < 0);
+}
+
+static int IsFull(const HuffmanTree* const tree) {
+ return (tree->num_nodes_ == tree->max_nodes_);
+}
+
+static void AssignChildren(HuffmanTree* const tree,
+ HuffmanTreeNode* const node) {
+ HuffmanTreeNode* const children = tree->root_ + tree->num_nodes_;
+ node->children_ = (int)(children - node);
+ assert(children - node == (int)(children - node));
+ tree->num_nodes_ += 2;
+ TreeNodeInit(children + 0);
+ TreeNodeInit(children + 1);
+}
+
+// A Huffman tree is a full binary tree; and in a full binary tree with L
+// leaves, the total number of nodes N = 2 * L - 1.
+static int HuffmanTreeMaxNodes(int num_leaves) {
+ return (2 * num_leaves - 1);
+}
+
+static int HuffmanTreeAllocate(HuffmanTree* const tree, int num_nodes) {
+ assert(tree != NULL);
+ tree->root_ =
+ (HuffmanTreeNode*)WebPSafeMalloc(num_nodes, sizeof(*tree->root_));
+ return (tree->root_ != NULL);
+}
+
+static int TreeInit(HuffmanTree* const tree, int num_leaves) {
+ assert(tree != NULL);
+ if (num_leaves == 0) return 0;
+ tree->max_nodes_ = HuffmanTreeMaxNodes(num_leaves);
+ assert(tree->max_nodes_ < (1 << 16)); // limit for the lut_jump_ table
+ if (!HuffmanTreeAllocate(tree, tree->max_nodes_)) return 0;
+ TreeNodeInit(tree->root_); // Initialize root.
+ tree->num_nodes_ = 1;
+ memset(tree->lut_bits_, 255, sizeof(tree->lut_bits_));
+ memset(tree->lut_jump_, 0, sizeof(tree->lut_jump_));
+ return 1;
+}
+
+void VP8LHuffmanTreeFree(HuffmanTree* const tree) {
+ if (tree != NULL) {
+ WebPSafeFree(tree->root_);
+ tree->root_ = NULL;
+ tree->max_nodes_ = 0;
+ tree->num_nodes_ = 0;
+ }
+}
+
+HTreeGroup* VP8LHtreeGroupsNew(int num_htree_groups) {
+ HTreeGroup* const htree_groups =
+ (HTreeGroup*)WebPSafeCalloc(num_htree_groups, sizeof(*htree_groups));
+ assert(num_htree_groups <= MAX_HTREE_GROUPS);
+ if (htree_groups == NULL) {
+ return NULL;
+ }
+ return htree_groups;
+}
+
+void VP8LHtreeGroupsFree(HTreeGroup* htree_groups, int num_htree_groups) {
+ if (htree_groups != NULL) {
+ int i, j;
+ for (i = 0; i < num_htree_groups; ++i) {
+ HuffmanTree* const htrees = htree_groups[i].htrees_;
+ for (j = 0; j < HUFFMAN_CODES_PER_META_CODE; ++j) {
+ VP8LHuffmanTreeFree(&htrees[j]);
+ }
+ }
+ WebPSafeFree(htree_groups);
+ }
+}
+
+int VP8LHuffmanCodeLengthsToCodes(
+ const int* const code_lengths, int code_lengths_size,
+ int* const huff_codes) {
+ int symbol;
+ int code_len;
+ int code_length_hist[MAX_ALLOWED_CODE_LENGTH + 1] = { 0 };
+ int curr_code;
+ int next_codes[MAX_ALLOWED_CODE_LENGTH + 1] = { 0 };
+ int max_code_length = 0;
+
+ assert(code_lengths != NULL);
+ assert(code_lengths_size > 0);
+ assert(huff_codes != NULL);
+
+ // Calculate max code length.
+ for (symbol = 0; symbol < code_lengths_size; ++symbol) {
+ if (code_lengths[symbol] > max_code_length) {
+ max_code_length = code_lengths[symbol];
+ }
+ }
+ if (max_code_length > MAX_ALLOWED_CODE_LENGTH) return 0;
+
+ // Calculate code length histogram.
+ for (symbol = 0; symbol < code_lengths_size; ++symbol) {
+ ++code_length_hist[code_lengths[symbol]];
+ }
+ code_length_hist[0] = 0;
+
+ // Calculate the initial values of 'next_codes' for each code length.
+ // next_codes[code_len] denotes the code to be assigned to the next symbol
+ // of code length 'code_len'.
+ curr_code = 0;
+ next_codes[0] = -1; // Unused, as code length = 0 implies code doesn't exist.
+ for (code_len = 1; code_len <= max_code_length; ++code_len) {
+ curr_code = (curr_code + code_length_hist[code_len - 1]) << 1;
+ next_codes[code_len] = curr_code;
+ }
+
+ // Get symbols.
+ for (symbol = 0; symbol < code_lengths_size; ++symbol) {
+ if (code_lengths[symbol] > 0) {
+ huff_codes[symbol] = next_codes[code_lengths[symbol]]++;
+ } else {
+ huff_codes[symbol] = NON_EXISTENT_SYMBOL;
+ }
+ }
+ return 1;
+}
+
+#ifndef USE_LUT_REVERSE_BITS
+
+static int ReverseBitsShort(int bits, int num_bits) {
+ int retval = 0;
+ int i;
+ assert(num_bits <= 8); // Not a hard requirement, just for coherency.
+ for (i = 0; i < num_bits; ++i) {
+ retval <<= 1;
+ retval |= bits & 1;
+ bits >>= 1;
+ }
+ return retval;
+}
+
+#else
+
+static const uint8_t kReversedBits[16] = { // Pre-reversed 4-bit values.
+ 0x0, 0x8, 0x4, 0xc, 0x2, 0xa, 0x6, 0xe,
+ 0x1, 0x9, 0x5, 0xd, 0x3, 0xb, 0x7, 0xf
+};
+
+static int ReverseBitsShort(int bits, int num_bits) {
+ const uint8_t v = (kReversedBits[bits & 0xf] << 4) | kReversedBits[bits >> 4];
+ assert(num_bits <= 8);
+ return v >> (8 - num_bits);
+}
+
+#endif
+
+static int TreeAddSymbol(HuffmanTree* const tree,
+ int symbol, int code, int code_length) {
+ int step = HUFF_LUT_BITS;
+ int base_code;
+ HuffmanTreeNode* node = tree->root_;
+ const HuffmanTreeNode* const max_node = tree->root_ + tree->max_nodes_;
+ assert(symbol == (int16_t)symbol);
+ if (code_length <= HUFF_LUT_BITS) {
+ int i;
+ base_code = ReverseBitsShort(code, code_length);
+ for (i = 0; i < (1 << (HUFF_LUT_BITS - code_length)); ++i) {
+ const int idx = base_code | (i << code_length);
+ tree->lut_symbol_[idx] = (int16_t)symbol;
+ tree->lut_bits_[idx] = code_length;
+ }
+ } else {
+ base_code = ReverseBitsShort((code >> (code_length - HUFF_LUT_BITS)),
+ HUFF_LUT_BITS);
+ }
+ while (code_length-- > 0) {
+ if (node >= max_node) {
+ return 0;
+ }
+ if (NodeIsEmpty(node)) {
+ if (IsFull(tree)) return 0; // error: too many symbols.
+ AssignChildren(tree, node);
+ } else if (!HuffmanTreeNodeIsNotLeaf(node)) {
+ return 0; // leaf is already occupied.
+ }
+ node += node->children_ + ((code >> code_length) & 1);
+ if (--step == 0) {
+ tree->lut_jump_[base_code] = (int16_t)(node - tree->root_);
+ }
+ }
+ if (NodeIsEmpty(node)) {
+ node->children_ = 0; // turn newly created node into a leaf.
+ } else if (HuffmanTreeNodeIsNotLeaf(node)) {
+ return 0; // trying to assign a symbol to already used code.
+ }
+ node->symbol_ = symbol; // Add symbol in this node.
+ return 1;
+}
+
+int VP8LHuffmanTreeBuildImplicit(HuffmanTree* const tree,
+ const int* const code_lengths,
+ int* const codes,
+ int code_lengths_size) {
+ int symbol;
+ int num_symbols = 0;
+ int root_symbol = 0;
+
+ assert(tree != NULL);
+ assert(code_lengths != NULL);
+
+ // Find out number of symbols and the root symbol.
+ for (symbol = 0; symbol < code_lengths_size; ++symbol) {
+ if (code_lengths[symbol] > 0) {
+ // Note: code length = 0 indicates non-existent symbol.
+ ++num_symbols;
+ root_symbol = symbol;
+ }
+ }
+
+ // Initialize the tree. Will fail for num_symbols = 0
+ if (!TreeInit(tree, num_symbols)) return 0;
+
+ // Build tree.
+ if (num_symbols == 1) { // Trivial case.
+ const int max_symbol = code_lengths_size;
+ if (root_symbol < 0 || root_symbol >= max_symbol) {
+ VP8LHuffmanTreeFree(tree);
+ return 0;
+ }
+ return TreeAddSymbol(tree, root_symbol, 0, 0);
+ } else { // Normal case.
+ int ok = 0;
+ memset(codes, 0, code_lengths_size * sizeof(*codes));
+
+ if (!VP8LHuffmanCodeLengthsToCodes(code_lengths, code_lengths_size,
+ codes)) {
+ goto End;
+ }
+
+ // Add symbols one-by-one.
+ for (symbol = 0; symbol < code_lengths_size; ++symbol) {
+ if (code_lengths[symbol] > 0) {
+ if (!TreeAddSymbol(tree, symbol, codes[symbol],
+ code_lengths[symbol])) {
+ goto End;
+ }
+ }
+ }
+ ok = 1;
+ End:
+ ok = ok && IsFull(tree);
+ if (!ok) VP8LHuffmanTreeFree(tree);
+ return ok;
+ }
+}
+
+int VP8LHuffmanTreeBuildExplicit(HuffmanTree* const tree,
+ const int* const code_lengths,
+ const int* const codes,
+ const int* const symbols, int max_symbol,
+ int num_symbols) {
+ int ok = 0;
+ int i;
+ assert(tree != NULL);
+ assert(code_lengths != NULL);
+ assert(codes != NULL);
+ assert(symbols != NULL);
+
+ // Initialize the tree. Will fail if num_symbols = 0.
+ if (!TreeInit(tree, num_symbols)) return 0;
+
+ // Add symbols one-by-one.
+ for (i = 0; i < num_symbols; ++i) {
+ if (codes[i] != NON_EXISTENT_SYMBOL) {
+ if (symbols[i] < 0 || symbols[i] >= max_symbol) {
+ goto End;
+ }
+ if (!TreeAddSymbol(tree, symbols[i], codes[i], code_lengths[i])) {
+ goto End;
+ }
+ }
+ }
+ ok = 1;
+ End:
+ ok = ok && IsFull(tree);
+ if (!ok) VP8LHuffmanTreeFree(tree);
+ return ok;
+}