path: root/libavcodec/elsdec.h (plain)
blob: 139a24ab8bbbbfc8e625131b609012e6ebfe3618

1	/*
2	* ELS (Entropy Logarithmic-Scale) decoder
3	*
4	* Copyright (c) 2013 Maxim Poliakovski
5	*
6	* This file is part of FFmpeg.
7	*
8	* FFmpeg is free software; you can redistribute it and/or
9	* modify it under the terms of the GNU Lesser General Public
10	* License as published by the Free Software Foundation; either
11	* version 2.1 of the License, or (at your option) any later version.
12	*
13	* FFmpeg is distributed in the hope that it will be useful,
14	* but WITHOUT ANY WARRANTY; without even the implied warranty of
15	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16	* Lesser General Public License for more details.
17	*
18	* You should have received a copy of the GNU Lesser General Public
19	* License along with FFmpeg; if not, write to the Free Software
20	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21	*/
22
23	/**
24	* @file
25	* Entropy Logarithmic-Scale binary arithmetic coder
26	*/
27
28	#ifndef AVCODEC_ELSDEC_H
29	#define AVCODEC_ELSDEC_H
30
31	#include <stdint.h>
32	#include <sys/types.h>
33
34	#define ELS_EXPGOLOMB_LEN 10
35
36	typedef struct ElsDecCtx {
37	const uint8_t *in_buf;
38	unsigned x;
39	size_t data_size;
40	int j, t, diff, err;
41	} ElsDecCtx;
42
43	typedef struct ElsRungNode {
44	uint8_t rung;
45	uint16_t next_index;
46	} ElsRungNode;
47
48	typedef struct ElsUnsignedRung {
49	uint8_t prefix_rung[ELS_EXPGOLOMB_LEN + 1];
50	ElsRungNode *rem_rung_list;
51	size_t rung_list_size;
52	uint16_t avail_index;
53	} ElsUnsignedRung;
54
55	void ff_els_decoder_init(ElsDecCtx *ctx, const uint8_t *in, size_t data_size);
56	void ff_els_decoder_uninit(ElsUnsignedRung *rung);
57	int ff_els_decode_bit(ElsDecCtx *ctx, unsigned char *rung);
58	unsigned ff_els_decode_unsigned(ElsDecCtx *ctx, ElsUnsignedRung *ur);
59
60	#endif /* AVCODEC_ELSDEC_H */
61