#define WEBP_UTILS_HUFFMAN_H_
#include <assert.h>
+#include "../webp/format_constants.h"
#include "../webp/types.h"
-#if defined(__cplusplus) || defined(c_plusplus)
+#ifdef __cplusplus
extern "C" {
#endif
} 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(
+// Huffman Tree group.
+typedef struct HTreeGroup HTreeGroup;
+struct HTreeGroup {
+ HuffmanTree htrees_[HUFFMAN_CODES_PER_META_CODE];
+};
+
+// 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.
// Releases the nodes of the Huffman tree.
// Note: It does NOT free 'tree' itself.
-void HuffmanTreeRelease(HuffmanTree* const tree);
+void VP8LHuffmanTreeFree(HuffmanTree* const tree);
+
+// Creates the instance of HTreeGroup with specified number of tree-groups.
+HTreeGroup* VP8LHtreeGroupsNew(int num_htree_groups);
+
+// Releases the memory allocated for HTreeGroup.
+void VP8LHtreeGroupsFree(HTreeGroup* htree_groups, int num_htree_groups);
// Builds Huffman tree assuming code lengths are implicitly in symbol order.
+// The 'huff_codes' and 'code_lengths' are pre-allocated temporary memory
+// buffers, used for creating the huffman tree.
// Returns false in case of error (invalid tree or memory error).
-int HuffmanTreeBuildImplicit(HuffmanTree* const tree,
- const int* const code_lengths,
- int code_lengths_size);
+int VP8LHuffmanTreeBuildImplicit(HuffmanTree* const tree,
+ const int* const code_lengths,
+ int* const huff_codes,
+ int code_lengths_size);
// Build a Huffman tree with explicitly given lists of code lengths, codes
// and symbols. Verifies that all symbols added are smaller than max_symbol.
// Returns false in case of an invalid symbol, invalid tree or memory error.
-int HuffmanTreeBuildExplicit(HuffmanTree* const tree,
- const int* const code_lengths,
- const int* const codes,
- const int* const symbols, int max_symbol,
- int num_symbols);
+int VP8LHuffmanTreeBuildExplicit(HuffmanTree* const tree,
+ const int* const code_lengths,
+ const int* const codes,
+ 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);
-
+int VP8LHuffmanCodeLengthsToCodes(const int* const code_lengths,
+ int code_lengths_size, int* const huff_codes);
-#if defined(__cplusplus) || defined(c_plusplus)
+#ifdef __cplusplus
} // extern "C"
#endif