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