xref: /third_party/ffmpeg/libavcodec/huffman.h (revision cabdff1a)
1/*
2 * Copyright (C) 2007  Aurelien Jacobs <aurel@gnuage.org>
3 *
4 * This file is part of FFmpeg.
5 *
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21/**
22 * @file
23 * huffman tree builder and VLC generator
24 */
25
26#ifndef AVCODEC_HUFFMAN_H
27#define AVCODEC_HUFFMAN_H
28
29#include <stdint.h>
30
31#include "vlc.h"
32
33typedef struct Node {
34    int16_t  sym;
35    int16_t  n0;
36    uint32_t count;
37} Node;
38
39#define FF_HUFFMAN_FLAG_HNODE_FIRST 0x01
40#define FF_HUFFMAN_FLAG_ZERO_COUNT  0x02
41#define FF_HUFFMAN_BITS 10
42
43typedef int (*HuffCmp)(const void *va, const void *vb);
44int ff_huff_build_tree(void *logctx, VLC *vlc, int nb_codes, int nb_bits,
45                       Node *nodes, HuffCmp cmp, int flags);
46
47int ff_huff_gen_len_table(uint8_t *dst, const uint64_t *stats, int n, int skip0);
48
49#endif /* AVCODEC_HUFFMAN_H */
50