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 Libav.
   7  *
   8  * Libav 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  * Libav 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 Libav; 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/common.h"
  30 #include "libavutil/intreadwrite.h"
  31
  32 typedef struct GetByteContext {
  33     const uint8_t *buffer, *buffer_end, *buffer_start;
  34 } GetByteContext;
  35
  36 typedef struct PutByteContext {
  37     uint8_t *buffer, *buffer_end, *buffer_start;
  38     int eof;
  39 } PutByteContext;
  40
  41 #define DEF(type, name, bytes, read, write)                                  \
  42 static av_always_inline type bytestream_get_ ## name(const uint8_t **b)        \
  43 {                                                                              \
  44     (*b) += bytes;                                                             \
  45     return read(*b - bytes);                                                   \
  46 }                                                                              \
  47 static av_always_inline void bytestream_put_ ## name(uint8_t **b,              \
  48                                                      const type value)         \
  49 {                                                                              \
  50     write(*b, value);                                                          \
  51     (*b) += bytes;                                                             \
  52 }                                                                              \
  53 static av_always_inline void bytestream2_put_ ## name ## u(PutByteContext *p,  \
  54                                                            const type value)   \
  55 {                                                                              \
  56     bytestream_put_ ## name(&p->buffer, value);                                \
  57 }                                                                              \
  58 static av_always_inline void bytestream2_put_ ## name(PutByteContext *p,       \
  59                                                       const type value)        \
  60 {                                                                              \
  61     if (!p->eof && (p->buffer_end - p->buffer >= bytes)) {                     \
  62         write(p->buffer, value);                                               \
  63         p->buffer += bytes;                                                    \
  64     } else                                                                     \
  65         p->eof = 1;                                                            \
  66 }                                                                              \
  67 static av_always_inline type bytestream2_get_ ## name ## u(GetByteContext *g)  \
  68 {                                                                              \
  69     return bytestream_get_ ## name(&g->buffer);                                \
  70 }                                                                              \
  71 static av_always_inline type bytestream2_get_ ## name(GetByteContext *g)       \
  72 {                                                                              \
  73     if (g->buffer_end - g->buffer < bytes) {                                   \
  74         g->buffer = g->buffer_end;                                             \
  75         return 0;                                                              \
  76     }                                                                          \
  77     return bytestream2_get_ ## name ## u(g);                                   \
  78 }                                                                              \
  79 static av_always_inline type bytestream2_peek_ ## name(GetByteContext *g)      \
  80 {                                                                              \
  81     if (g->buffer_end - g->buffer < bytes)                                     \
  82         return 0;                                                              \
  83     return read(g->buffer);                                                    \
  84 }
  85
  86 DEF(uint64_t,     le64, 8, AV_RL64, AV_WL64)
  87 DEF(unsigned int, le32, 4, AV_RL32, AV_WL32)
  88 DEF(unsigned int, le24, 3, AV_RL24, AV_WL24)
  89 DEF(unsigned int, le16, 2, AV_RL16, AV_WL16)
  90 DEF(uint64_t,     be64, 8, AV_RB64, AV_WB64)
  91 DEF(unsigned int, be32, 4, AV_RB32, AV_WB32)
  92 DEF(unsigned int, be24, 3, AV_RB24, AV_WB24)
  93 DEF(unsigned int, be16, 2, AV_RB16, AV_WB16)
  94 DEF(unsigned int, byte, 1, AV_RB8 , AV_WB8)
  95
  96 #if HAVE_BIGENDIAN
  97 #   define bytestream2_get_ne16  bytestream2_get_be16
  98 #   define bytestream2_get_ne24  bytestream2_get_be24
  99 #   define bytestream2_get_ne32  bytestream2_get_be32
 100 #   define bytestream2_get_ne64  bytestream2_get_be64
 101 #   define bytestream2_get_ne16u bytestream2_get_be16u
 102 #   define bytestream2_get_ne24u bytestream2_get_be24u
 103 #   define bytestream2_get_ne32u bytestream2_get_be32u
 104 #   define bytestream2_get_ne64u bytestream2_get_be64u
 105 #   define bytestream2_put_ne16  bytestream2_put_be16
 106 #   define bytestream2_put_ne24  bytestream2_put_be24
 107 #   define bytestream2_put_ne32  bytestream2_put_be32
 108 #   define bytestream2_put_ne64  bytestream2_put_be64
 109 #   define bytestream2_peek_ne16 bytestream2_peek_be16
 110 #   define bytestream2_peek_ne24 bytestream2_peek_be24
 111 #   define bytestream2_peek_ne32 bytestream2_peek_be32
 112 #   define bytestream2_peek_ne64 bytestream2_peek_be64
 113 #else
 114 #   define bytestream2_get_ne16  bytestream2_get_le16
 115 #   define bytestream2_get_ne24  bytestream2_get_le24
 116 #   define bytestream2_get_ne32  bytestream2_get_le32
 117 #   define bytestream2_get_ne64  bytestream2_get_le64
 118 #   define bytestream2_get_ne16u bytestream2_get_le16u
 119 #   define bytestream2_get_ne24u bytestream2_get_le24u
 120 #   define bytestream2_get_ne32u bytestream2_get_le32u
 121 #   define bytestream2_get_ne64u bytestream2_get_le64u
 122 #   define bytestream2_put_ne16  bytestream2_put_le16
 123 #   define bytestream2_put_ne24  bytestream2_put_le24
 124 #   define bytestream2_put_ne32  bytestream2_put_le32
 125 #   define bytestream2_put_ne64  bytestream2_put_le64
 126 #   define bytestream2_peek_ne16 bytestream2_peek_le16
 127 #   define bytestream2_peek_ne24 bytestream2_peek_le24
 128 #   define bytestream2_peek_ne32 bytestream2_peek_le32
 129 #   define bytestream2_peek_ne64 bytestream2_peek_le64
 130 #endif
 131
 132 static av_always_inline void bytestream2_init(GetByteContext *g,
 133                                               const uint8_t *buf,
 134                                               int buf_size)
 135 {
 136     g->buffer       = buf;
 137     g->buffer_start = buf;
 138     g->buffer_end   = buf + buf_size;
 139 }
 140
 141 static av_always_inline void bytestream2_init_writer(PutByteContext *p,
 142                                                      uint8_t *buf,
 143                                                      int buf_size)
 144 {
 145     p->buffer       = buf;
 146     p->buffer_start = buf;
 147     p->buffer_end   = buf + buf_size;
 148     p->eof          = 0;
 149 }
 150
 151 static av_always_inline unsigned int bytestream2_get_bytes_left(GetByteContext *g)
 152 {
 153     return g->buffer_end - g->buffer;
 154 }
 155
 156 static av_always_inline unsigned int bytestream2_get_bytes_left_p(PutByteContext *p)
 157 {
 158     return p->buffer_end - p->buffer;
 159 }
 160
 161 static av_always_inline void bytestream2_skip(GetByteContext *g,
 162                                               unsigned int size)
 163 {
 164     g->buffer += FFMIN(g->buffer_end - g->buffer, size);
 165 }
 166
 167 static av_always_inline void bytestream2_skipu(GetByteContext *g,
 168                                                unsigned int size)
 169 {
 170     g->buffer += size;
 171 }
 172
 173 static av_always_inline void bytestream2_skip_p(PutByteContext *p,
 174                                                 unsigned int size)
 175 {
 176     int size2;
 177     if (p->eof)
 178         return;
 179     size2 = FFMIN(p->buffer_end - p->buffer, size);
 180     if (size2 != size)
 181         p->eof = 1;
 182     p->buffer += size2;
 183 }
 184
 185 static av_always_inline int bytestream2_tell(GetByteContext *g)
 186 {
 187     return (int)(g->buffer - g->buffer_start);
 188 }
 189
 190 static av_always_inline int bytestream2_tell_p(PutByteContext *p)
 191 {
 192     return (int)(p->buffer - p->buffer_start);
 193 }
 194
 195 static av_always_inline int bytestream2_size(GetByteContext *g)
 196 {
 197     return (int)(g->buffer_end - g->buffer_start);
 198 }
 199
 200 static av_always_inline int bytestream2_size_p(PutByteContext *p)
 201 {
 202     return (int)(p->buffer_end - p->buffer_start);
 203 }
 204
 205 static av_always_inline int bytestream2_seek(GetByteContext *g,
 206                                              int offset,
 207                                              int whence)
 208 {
 209     switch (whence) {
 210     case SEEK_CUR:
 211         offset     = av_clip(offset, -(g->buffer - g->buffer_start),
 212                              g->buffer_end - g->buffer);
 213         g->buffer += offset;
 214         break;
 215     case SEEK_END:
 216         offset    = av_clip(offset, -(g->buffer_end - g->buffer_start), 0);
 217         g->buffer = g->buffer_end + offset;
 218         break;
 219     case SEEK_SET:
 220         offset    = av_clip(offset, 0, g->buffer_end - g->buffer_start);
 221         g->buffer = g->buffer_start + offset;
 222         break;
 223     default:
 224         return AVERROR(EINVAL);
 225     }
 226     return bytestream2_tell(g);
 227 }
 228
 229 static av_always_inline int bytestream2_seek_p(PutByteContext *p,
 230                                                int offset,
 231                                                int whence)
 232 {
 233     p->eof = 0;
 234     switch (whence) {
 235     case SEEK_CUR:
 236         if (p->buffer_end - p->buffer < offset)
 237             p->eof = 1;
 238         offset     = av_clip(offset, -(p->buffer - p->buffer_start),
 239                              p->buffer_end - p->buffer);
 240         p->buffer += offset;
 241         break;
 242     case SEEK_END:
 243         if (offset > 0)
 244             p->eof = 1;
 245         offset    = av_clip(offset, -(p->buffer_end - p->buffer_start), 0);
 246         p->buffer = p->buffer_end + offset;
 247         break;
 248     case SEEK_SET:
 249         if (p->buffer_end - p->buffer_start < offset)
 250             p->eof = 1;
 251         offset    = av_clip(offset, 0, p->buffer_end - p->buffer_start);
 252         p->buffer = p->buffer_start + offset;
 253         break;
 254     default:
 255         return AVERROR(EINVAL);
 256     }
 257     return bytestream2_tell_p(p);
 258 }
 259
 260 static av_always_inline unsigned int bytestream2_get_buffer(GetByteContext *g,
 261                                                             uint8_t *dst,
 262                                                             unsigned int size)
 263 {
 264     int size2 = FFMIN(g->buffer_end - g->buffer, size);
 265     memcpy(dst, g->buffer, size2);
 266     g->buffer += size2;
 267     return size2;
 268 }
 269
 270 static av_always_inline unsigned int bytestream2_get_bufferu(GetByteContext *g,
 271                                                              uint8_t *dst,
 272                                                              unsigned int size)
 273 {
 274     memcpy(dst, g->buffer, size);
 275     g->buffer += size;
 276     return size;
 277 }
 278
 279 static av_always_inline unsigned int bytestream2_put_buffer(PutByteContext *p,
 280                                                             const uint8_t *src,
 281                                                             unsigned int size)
 282 {
 283     int size2;
 284     if (p->eof)
 285         return 0;
 286     size2 = FFMIN(p->buffer_end - p->buffer, size);
 287     if (size2 != size)
 288         p->eof = 1;
 289     memcpy(p->buffer, src, size2);
 290     p->buffer += size2;
 291     return size2;
 292 }
 293
 294 static av_always_inline unsigned int bytestream2_put_bufferu(PutByteContext *p,
 295                                                              const uint8_t *src,
 296                                                              unsigned int size)
 297 {
 298     memcpy(p->buffer, src, size);
 299     p->buffer += size;
 300     return size;
 301 }
 302
 303 static av_always_inline void bytestream2_set_buffer(PutByteContext *p,
 304                                                     const uint8_t c,
 305                                                     unsigned int size)
 306 {
 307     int size2;
 308     if (p->eof)
 309         return;
 310     size2 = FFMIN(p->buffer_end - p->buffer, size);
 311     if (size2 != size)
 312         p->eof = 1;
 313     memset(p->buffer, c, size2);
 314     p->buffer += size2;
 315 }
 316
 317 static av_always_inline void bytestream2_set_bufferu(PutByteContext *p,
 318                                                      const uint8_t c,
 319                                                      unsigned int size)
 320 {
 321     memset(p->buffer, c, size);
 322     p->buffer += size;
 323 }
 324
 325 static av_always_inline unsigned int bytestream2_get_eof(PutByteContext *p)
 326 {
 327     return p->eof;
 328 }
 329
 330 static av_always_inline unsigned int bytestream2_copy_bufferu(PutByteContext *p,
 331                                                               GetByteContext *g,
 332                                                               unsigned int size)
 333 {
 334     memcpy(p->buffer, g->buffer, size);
 335     p->buffer += size;
 336     g->buffer += size;
 337     return size;
 338 }
 339
 340 static av_always_inline unsigned int bytestream2_copy_buffer(PutByteContext *p,
 341                                                              GetByteContext *g,
 342                                                              unsigned int size)
 343 {
 344     int size2;
 345
 346     if (p->eof)
 347         return 0;
 348     size  = FFMIN(g->buffer_end - g->buffer, size);
 349     size2 = FFMIN(p->buffer_end - p->buffer, size);
 350     if (size2 != size)
 351         p->eof = 1;
 352
 353     return bytestream2_copy_bufferu(p, g, size2);
 354 }
 355
 356 static av_always_inline unsigned int bytestream_get_buffer(const uint8_t **b,
 357                                                            uint8_t *dst,
 358                                                            unsigned int size)
 359 {
 360     memcpy(dst, *b, size);
 361     (*b) += size;
 362     return size;
 363 }
 364
 365 static av_always_inline void bytestream_put_buffer(uint8_t **b,
 366                                                    const uint8_t *src,
 367                                                    unsigned int size)
 368 {
 369     memcpy(*b, src, size);
 370     (*b) += size;
 371 }
 372
 373 #endif /* AVCODEC_BYTESTREAM_H */