libavcodec/elsdec.h

   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 */