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