git.sesse.net Git - ffmpeg/blob - libavcodec/bytestream.h

   1 /*
   2  * Bytestream functions
   3  * copyright (c) 2006 Baptiste Coudurier <baptiste.coudurier@free.fr>
   4  *
   5  * This file is part of FFmpeg.
   6  *
   7  * FFmpeg is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * FFmpeg is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with FFmpeg; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 #ifndef AVCODEC_BYTESTREAM_H
  23 #define AVCODEC_BYTESTREAM_H
  24
  25 #include <string.h>
  26 #include "libavutil/common.h"
  27 #include "libavutil/intreadwrite.h"
  28
  29 typedef struct {
  30     const uint8_t *buffer, *buffer_end, *buffer_start;
  31 } GetByteContext;
  32
  33 #define DEF_T(type, name, bytes, read, write)                             \
  34 static av_always_inline type bytestream_get_ ## name(const uint8_t **b){\
  35     (*b) += bytes;\
  36     return read(*b - bytes);\
  37 }\
  38 static av_always_inline void bytestream_put_ ##name(uint8_t **b, const type value){\
  39     write(*b, value);\
  40     (*b) += bytes;\
  41 }\
  42 static av_always_inline type bytestream2_get_ ## name ## u(GetByteContext *g)\
  43 {\
  44     return bytestream_get_ ## name(&g->buffer);\
  45 }\
  46 static av_always_inline type bytestream2_get_ ## name(GetByteContext *g)\
  47 {\
  48     if (g->buffer_end - g->buffer < bytes)\
  49         return 0;\
  50     return bytestream2_get_ ## name ## u(g);\
  51 }\
  52 static av_always_inline type bytestream2_peek_ ## name(GetByteContext *g)\
  53 {\
  54     if (g->buffer_end - g->buffer < bytes)\
  55         return 0;\
  56     return read(g->buffer);\
  57 }
  58
  59 #define DEF(name, bytes, read, write) \
  60     DEF_T(unsigned int, name, bytes, read, write)
  61 #define DEF64(name, bytes, read, write) \
  62     DEF_T(uint64_t, name, bytes, read, write)
  63
  64 DEF64(le64, 8, AV_RL64, AV_WL64)
  65 DEF  (le32, 4, AV_RL32, AV_WL32)
  66 DEF  (le24, 3, AV_RL24, AV_WL24)
  67 DEF  (le16, 2, AV_RL16, AV_WL16)
  68 DEF64(be64, 8, AV_RB64, AV_WB64)
  69 DEF  (be32, 4, AV_RB32, AV_WB32)
  70 DEF  (be24, 3, AV_RB24, AV_WB24)
  71 DEF  (be16, 2, AV_RB16, AV_WB16)
  72 DEF  (byte, 1, AV_RB8 , AV_WB8 )
  73
  74 #undef DEF
  75 #undef DEF64
  76 #undef DEF_T
  77
  78 #if HAVE_BIGENDIAN
  79 #   define bytestream2_get_ne16  bytestream2_get_be16
  80 #   define bytestream2_get_ne24  bytestream2_get_be24
  81 #   define bytestream2_get_ne32  bytestream2_get_be32
  82 #   define bytestream2_get_ne64  bytestream2_get_be64
  83 #   define bytestream2_get_ne16u bytestream2_get_be16u
  84 #   define bytestream2_get_ne24u bytestream2_get_be24u
  85 #   define bytestream2_get_ne32u bytestream2_get_be32u
  86 #   define bytestream2_get_ne64u bytestream2_get_be64u
  87 #   define bytestream2_put_ne16  bytestream2_put_be16
  88 #   define bytestream2_put_ne24  bytestream2_put_be24
  89 #   define bytestream2_put_ne32  bytestream2_put_be32
  90 #   define bytestream2_put_ne64  bytestream2_put_be64
  91 #   define bytestream2_peek_ne16 bytestream2_peek_be16
  92 #   define bytestream2_peek_ne24 bytestream2_peek_be24
  93 #   define bytestream2_peek_ne32 bytestream2_peek_be32
  94 #   define bytestream2_peek_ne64 bytestream2_peek_be64
  95 #else
  96 #   define bytestream2_get_ne16  bytestream2_get_le16
  97 #   define bytestream2_get_ne24  bytestream2_get_le24
  98 #   define bytestream2_get_ne32  bytestream2_get_le32
  99 #   define bytestream2_get_ne64  bytestream2_get_le64
 100 #   define bytestream2_get_ne16u bytestream2_get_le16u
 101 #   define bytestream2_get_ne24u bytestream2_get_le24u
 102 #   define bytestream2_get_ne32u bytestream2_get_le32u
 103 #   define bytestream2_get_ne64u bytestream2_get_le64u
 104 #   define bytestream2_put_ne16  bytestream2_put_le16
 105 #   define bytestream2_put_ne24  bytestream2_put_le24
 106 #   define bytestream2_put_ne32  bytestream2_put_le32
 107 #   define bytestream2_put_ne64  bytestream2_put_le64
 108 #   define bytestream2_peek_ne16 bytestream2_peek_le16
 109 #   define bytestream2_peek_ne24 bytestream2_peek_le24
 110 #   define bytestream2_peek_ne32 bytestream2_peek_le32
 111 #   define bytestream2_peek_ne64 bytestream2_peek_le64
 112 #endif
 113
 114 static av_always_inline void bytestream2_init(GetByteContext *g,
 115                                               const uint8_t *buf, int buf_size)
 116 {
 117     g->buffer =  buf;
 118     g->buffer_start = buf;
 119     g->buffer_end = buf + buf_size;
 120 }
 121
 122 static av_always_inline unsigned int bytestream2_get_bytes_left(GetByteContext *g)
 123 {
 124     return g->buffer_end - g->buffer;
 125 }
 126
 127 static av_always_inline void bytestream2_skip(GetByteContext *g,
 128                                               unsigned int size)
 129 {
 130     g->buffer += FFMIN(g->buffer_end - g->buffer, size);
 131 }
 132
 133 static av_always_inline int bytestream2_tell(GetByteContext *g)
 134 {
 135     return (int)(g->buffer - g->buffer_start);
 136 }
 137
 138 static av_always_inline int bytestream2_seek(GetByteContext *g, int offset,
 139                                              int whence)
 140 {
 141     switch (whence) {
 142     case SEEK_CUR:
 143         offset = av_clip(offset, -(g->buffer - g->buffer_start),
 144                          g->buffer_end - g->buffer);
 145         g->buffer += offset;
 146         break;
 147     case SEEK_END:
 148         offset = av_clip(offset, -(g->buffer_end - g->buffer_start), 0);
 149         g->buffer = g->buffer_end + offset;
 150         break;
 151     case SEEK_SET:
 152         offset = av_clip(offset, 0, g->buffer_end - g->buffer_start);
 153         g->buffer = g->buffer_start + offset;
 154         break;
 155     default:
 156         return AVERROR(EINVAL);
 157     }
 158     return bytestream2_tell(g);
 159 }
 160
 161 static av_always_inline unsigned int bytestream2_get_buffer(GetByteContext *g,
 162                                                             uint8_t *dst,
 163                                                             unsigned int size)
 164 {
 165     int size2 = FFMIN(g->buffer_end - g->buffer, size);
 166     memcpy(dst, g->buffer, size2);
 167     g->buffer += size2;
 168     return size2;
 169 }
 170
 171 static av_always_inline unsigned int bytestream_get_buffer(const uint8_t **b, uint8_t *dst, unsigned int size)
 172 {
 173     memcpy(dst, *b, size);
 174     (*b) += size;
 175     return size;
 176 }
 177
 178 static av_always_inline void bytestream_put_buffer(uint8_t **b, const uint8_t *src, unsigned int size)
 179 {
 180     memcpy(*b, src, size);
 181     (*b) += size;
 182 }
 183
 184 #endif /* AVCODEC_BYTESTREAM_H */