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