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

   1 /*
   2  * Bytestream functions
   3  * copyright (c) 2006 Baptiste Coudurier <baptiste.coudurier@free.fr>
   4  * Copyright (c) 2012 Aneesh Dogra (lionaneesh) <lionaneesh@gmail.com>
   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 #ifndef AVCODEC_BYTESTREAM_H
  24 #define AVCODEC_BYTESTREAM_H
  25
  26 #include <stdint.h>
  27 #include <string.h>
  28
  29 #include "libavutil/avassert.h"
  30 #include "libavutil/common.h"
  31 #include "libavutil/intreadwrite.h"
  32
  33 typedef struct GetByteContext {
  34     const uint8_t *buffer, *buffer_end, *buffer_start;
  35 } GetByteContext;
  36
  37 typedef struct PutByteContext {
  38     uint8_t *buffer, *buffer_end, *buffer_start;
  39     int eof;
  40 } PutByteContext;
  41
  42 #define DEF(type, name, bytes, read, write)                                  \
  43 static av_always_inline type bytestream_get_ ## name(const uint8_t **b)        \
  44 {                                                                              \
  45     (*b) += bytes;                                                             \
  46     return read(*b - bytes);                                                   \
  47 }                                                                              \
  48 static av_always_inline void bytestream_put_ ## name(uint8_t **b,              \
  49                                                      const type value)         \
  50 {                                                                              \
  51     write(*b, value);                                                          \
  52     (*b) += bytes;                                                             \
  53 }                                                                              \
  54 static av_always_inline void bytestream2_put_ ## name ## u(PutByteContext *p,  \
  55                                                            const type value)   \
  56 {                                                                              \
  57     bytestream_put_ ## name(&p->buffer, value);                                \
  58 }                                                                              \
  59 static av_always_inline void bytestream2_put_ ## name(PutByteContext *p,       \
  60                                                       const type value)        \
  61 {                                                                              \
  62     if (!p->eof && (p->buffer_end - p->buffer >= bytes)) {                     \
  63         write(p->buffer, value);                                               \
  64         p->buffer += bytes;                                                    \
  65     } else                                                                     \
  66         p->eof = 1;                                                            \
  67 }                                                                              \
  68 static av_always_inline type bytestream2_get_ ## name ## u(GetByteContext *g)  \
  69 {                                                                              \
  70     return bytestream_get_ ## name(&g->buffer);                                \
  71 }                                                                              \
  72 static av_always_inline type bytestream2_get_ ## name(GetByteContext *g)       \
  73 {                                                                              \
  74     if (g->buffer_end - g->buffer < bytes) {                                   \
  75         g->buffer = g->buffer_end;                                             \
  76         return 0;                                                              \
  77     }                                                                          \
  78     return bytestream2_get_ ## name ## u(g);                                   \
  79 }                                                                              \
  80 static av_always_inline type bytestream2_peek_ ## name ## u(GetByteContext *g) \
  81 {                                                                              \
  82     return read(g->buffer);                                                    \
  83 }                                                                              \
  84 static av_always_inline type bytestream2_peek_ ## name(GetByteContext *g)      \
  85 {                                                                              \
  86     if (g->buffer_end - g->buffer < bytes)                                     \
  87         return 0;                                                              \
  88     return bytestream2_peek_ ## name ## u(g);                                  \
  89 }
  90
  91 DEF(uint64_t,     le64, 8, AV_RL64, AV_WL64)
  92 DEF(unsigned int, le32, 4, AV_RL32, AV_WL32)
  93 DEF(unsigned int, le24, 3, AV_RL24, AV_WL24)
  94 DEF(unsigned int, le16, 2, AV_RL16, AV_WL16)
  95 DEF(uint64_t,     be64, 8, AV_RB64, AV_WB64)
  96 DEF(unsigned int, be32, 4, AV_RB32, AV_WB32)
  97 DEF(unsigned int, be24, 3, AV_RB24, AV_WB24)
  98 DEF(unsigned int, be16, 2, AV_RB16, AV_WB16)
  99 DEF(unsigned int, byte, 1, AV_RB8 , AV_WB8)
 100
 101 #if AV_HAVE_BIGENDIAN
 102 #   define bytestream2_get_ne16  bytestream2_get_be16
 103 #   define bytestream2_get_ne24  bytestream2_get_be24
 104 #   define bytestream2_get_ne32  bytestream2_get_be32
 105 #   define bytestream2_get_ne64  bytestream2_get_be64
 106 #   define bytestream2_get_ne16u bytestream2_get_be16u
 107 #   define bytestream2_get_ne24u bytestream2_get_be24u
 108 #   define bytestream2_get_ne32u bytestream2_get_be32u
 109 #   define bytestream2_get_ne64u bytestream2_get_be64u
 110 #   define bytestream2_put_ne16  bytestream2_put_be16
 111 #   define bytestream2_put_ne24  bytestream2_put_be24
 112 #   define bytestream2_put_ne32  bytestream2_put_be32
 113 #   define bytestream2_put_ne64  bytestream2_put_be64
 114 #   define bytestream2_peek_ne16 bytestream2_peek_be16
 115 #   define bytestream2_peek_ne24 bytestream2_peek_be24
 116 #   define bytestream2_peek_ne32 bytestream2_peek_be32
 117 #   define bytestream2_peek_ne64 bytestream2_peek_be64
 118 #else
 119 #   define bytestream2_get_ne16  bytestream2_get_le16
 120 #   define bytestream2_get_ne24  bytestream2_get_le24
 121 #   define bytestream2_get_ne32  bytestream2_get_le32
 122 #   define bytestream2_get_ne64  bytestream2_get_le64
 123 #   define bytestream2_get_ne16u bytestream2_get_le16u
 124 #   define bytestream2_get_ne24u bytestream2_get_le24u
 125 #   define bytestream2_get_ne32u bytestream2_get_le32u
 126 #   define bytestream2_get_ne64u bytestream2_get_le64u
 127 #   define bytestream2_put_ne16  bytestream2_put_le16
 128 #   define bytestream2_put_ne24  bytestream2_put_le24
 129 #   define bytestream2_put_ne32  bytestream2_put_le32
 130 #   define bytestream2_put_ne64  bytestream2_put_le64
 131 #   define bytestream2_peek_ne16 bytestream2_peek_le16
 132 #   define bytestream2_peek_ne24 bytestream2_peek_le24
 133 #   define bytestream2_peek_ne32 bytestream2_peek_le32
 134 #   define bytestream2_peek_ne64 bytestream2_peek_le64
 135 #endif
 136
 137 static av_always_inline void bytestream2_init(GetByteContext *g,
 138                                               const uint8_t *buf,
 139                                               int buf_size)
 140 {
 141     av_assert0(buf_size >= 0);
 142     g->buffer       = buf;
 143     g->buffer_start = buf;
 144     g->buffer_end   = buf + buf_size;
 145 }
 146
 147 static av_always_inline void bytestream2_init_writer(PutByteContext *p,
 148                                                      uint8_t *buf,
 149                                                      int buf_size)
 150 {
 151     av_assert0(buf_size >= 0);
 152     p->buffer       = buf;
 153     p->buffer_start = buf;
 154     p->buffer_end   = buf + buf_size;
 155     p->eof          = 0;
 156 }
 157
 158 static av_always_inline int bytestream2_get_bytes_left(GetByteContext *g)
 159 {
 160     return g->buffer_end - g->buffer;
 161 }
 162
 163 static av_always_inline int bytestream2_get_bytes_left_p(PutByteContext *p)
 164 {
 165     return p->buffer_end - p->buffer;
 166 }
 167
 168 static av_always_inline void bytestream2_skip(GetByteContext *g,
 169                                               unsigned int size)
 170 {
 171     g->buffer += FFMIN(g->buffer_end - g->buffer, size);
 172 }
 173
 174 static av_always_inline void bytestream2_skipu(GetByteContext *g,
 175                                                unsigned int size)
 176 {
 177     g->buffer += size;
 178 }
 179
 180 static av_always_inline void bytestream2_skip_p(PutByteContext *p,
 181                                                 unsigned int size)
 182 {
 183     int size2;
 184     if (p->eof)
 185         return;
 186     size2 = FFMIN(p->buffer_end - p->buffer, size);
 187     if (size2 != size)
 188         p->eof = 1;
 189     p->buffer += size2;
 190 }
 191
 192 static av_always_inline int bytestream2_tell(GetByteContext *g)
 193 {
 194     return (int)(g->buffer - g->buffer_start);
 195 }
 196
 197 static av_always_inline int bytestream2_tell_p(PutByteContext *p)
 198 {
 199     return (int)(p->buffer - p->buffer_start);
 200 }
 201
 202 static av_always_inline int bytestream2_size(GetByteContext *g)
 203 {
 204     return (int)(g->buffer_end - g->buffer_start);
 205 }
 206
 207 static av_always_inline int bytestream2_size_p(PutByteContext *p)
 208 {
 209     return (int)(p->buffer_end - p->buffer_start);
 210 }
 211
 212 static av_always_inline int bytestream2_seek(GetByteContext *g,
 213                                              int offset,
 214                                              int whence)
 215 {
 216     switch (whence) {
 217     case SEEK_CUR:
 218         offset     = av_clip(offset, -(g->buffer - g->buffer_start),
 219                              g->buffer_end - g->buffer);
 220         g->buffer += offset;
 221         break;
 222     case SEEK_END:
 223         offset    = av_clip(offset, -(g->buffer_end - g->buffer_start), 0);
 224         g->buffer = g->buffer_end + offset;
 225         break;
 226     case SEEK_SET:
 227         offset    = av_clip(offset, 0, g->buffer_end - g->buffer_start);
 228         g->buffer = g->buffer_start + offset;
 229         break;
 230     default:
 231         return AVERROR(EINVAL);
 232     }
 233     return bytestream2_tell(g);
 234 }
 235
 236 static av_always_inline int bytestream2_seek_p(PutByteContext *p,
 237                                                int offset,
 238                                                int whence)
 239 {
 240     p->eof = 0;
 241     switch (whence) {
 242     case SEEK_CUR:
 243         if (p->buffer_end - p->buffer < offset)
 244             p->eof = 1;
 245         offset     = av_clip(offset, -(p->buffer - p->buffer_start),
 246                              p->buffer_end - p->buffer);
 247         p->buffer += offset;
 248         break;
 249     case SEEK_END:
 250         if (offset > 0)
 251             p->eof = 1;
 252         offset    = av_clip(offset, -(p->buffer_end - p->buffer_start), 0);
 253         p->buffer = p->buffer_end + offset;
 254         break;
 255     case SEEK_SET:
 256         if (p->buffer_end - p->buffer_start < offset)
 257             p->eof = 1;
 258         offset    = av_clip(offset, 0, p->buffer_end - p->buffer_start);
 259         p->buffer = p->buffer_start + offset;
 260         break;
 261     default:
 262         return AVERROR(EINVAL);
 263     }
 264     return bytestream2_tell_p(p);
 265 }
 266
 267 static av_always_inline unsigned int bytestream2_get_buffer(GetByteContext *g,
 268                                                             uint8_t *dst,
 269                                                             unsigned int size)
 270 {
 271     int size2 = FFMIN(g->buffer_end - g->buffer, size);
 272     memcpy(dst, g->buffer, size2);
 273     g->buffer += size2;
 274     return size2;
 275 }
 276
 277 static av_always_inline unsigned int bytestream2_get_bufferu(GetByteContext *g,
 278                                                              uint8_t *dst,
 279                                                              unsigned int size)
 280 {
 281     memcpy(dst, g->buffer, size);
 282     g->buffer += size;
 283     return size;
 284 }
 285
 286 static av_always_inline unsigned int bytestream2_put_buffer(PutByteContext *p,
 287                                                             const uint8_t *src,
 288                                                             unsigned int size)
 289 {
 290     int size2;
 291     if (p->eof)
 292         return 0;
 293     size2 = FFMIN(p->buffer_end - p->buffer, size);
 294     if (size2 != size)
 295         p->eof = 1;
 296     memcpy(p->buffer, src, size2);
 297     p->buffer += size2;
 298     return size2;
 299 }
 300
 301 static av_always_inline unsigned int bytestream2_put_bufferu(PutByteContext *p,
 302                                                              const uint8_t *src,
 303                                                              unsigned int size)
 304 {
 305     memcpy(p->buffer, src, size);
 306     p->buffer += size;
 307     return size;
 308 }
 309
 310 static av_always_inline void bytestream2_set_buffer(PutByteContext *p,
 311                                                     const uint8_t c,
 312                                                     unsigned int size)
 313 {
 314     int size2;
 315     if (p->eof)
 316         return;
 317     size2 = FFMIN(p->buffer_end - p->buffer, size);
 318     if (size2 != size)
 319         p->eof = 1;
 320     memset(p->buffer, c, size2);
 321     p->buffer += size2;
 322 }
 323
 324 static av_always_inline void bytestream2_set_bufferu(PutByteContext *p,
 325                                                      const uint8_t c,
 326                                                      unsigned int size)
 327 {
 328     memset(p->buffer, c, size);
 329     p->buffer += size;
 330 }
 331
 332 static av_always_inline unsigned int bytestream2_get_eof(PutByteContext *p)
 333 {
 334     return p->eof;
 335 }
 336
 337 static av_always_inline unsigned int bytestream2_copy_bufferu(PutByteContext *p,
 338                                                               GetByteContext *g,
 339                                                               unsigned int size)
 340 {
 341     memcpy(p->buffer, g->buffer, size);
 342     p->buffer += size;
 343     g->buffer += size;
 344     return size;
 345 }
 346
 347 static av_always_inline unsigned int bytestream2_copy_buffer(PutByteContext *p,
 348                                                              GetByteContext *g,
 349                                                              unsigned int size)
 350 {
 351     int size2;
 352
 353     if (p->eof)
 354         return 0;
 355     size  = FFMIN(g->buffer_end - g->buffer, size);
 356     size2 = FFMIN(p->buffer_end - p->buffer, size);
 357     if (size2 != size)
 358         p->eof = 1;
 359
 360     return bytestream2_copy_bufferu(p, g, size2);
 361 }
 362
 363 static av_always_inline unsigned int bytestream_get_buffer(const uint8_t **b,
 364                                                            uint8_t *dst,
 365                                                            unsigned int size)
 366 {
 367     memcpy(dst, *b, size);
 368     (*b) += size;
 369     return size;
 370 }
 371
 372 static av_always_inline void bytestream_put_buffer(uint8_t **b,
 373                                                    const uint8_t *src,
 374                                                    unsigned int size)
 375 {
 376     memcpy(*b, src, size);
 377     (*b) += size;
 378 }
 379
 380 #endif /* AVCODEC_BYTESTREAM_H */