git.sesse.net Git - vlc/blob - include/vlc_block_helper.h

   1 /*****************************************************************************
   2  * vlc_block_helper.h: Helper functions for data blocks management.
   3  *****************************************************************************
   4  * Copyright (C) 2003 the VideoLAN team
   5  * $Id$
   6  *
   7  * Authors: Gildas Bazin <gbazin@netcourrier.com>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  22  *****************************************************************************/
  23
  24 #ifndef VLC_BLOCK_HELPER_H
  25 #define VLC_BLOCK_HELPER_H 1
  26
  27 #include <vlc_block.h>
  28
  29 typedef struct block_bytestream_t
  30 {
  31     block_t             *p_chain;
  32     block_t             *p_block;
  33     size_t              i_offset;
  34
  35 } block_bytestream_t;
  36
  37 /*****************************************************************************
  38  * block_bytestream_t management
  39  *****************************************************************************/
  40 static inline block_bytestream_t block_BytestreamInit( void )
  41 {
  42     block_bytestream_t bytestream;
  43
  44     bytestream.i_offset = 0;
  45     bytestream.p_chain = bytestream.p_block = NULL;
  46
  47     return bytestream;
  48 }
  49
  50 static inline void block_BytestreamRelease( block_bytestream_t *p_bytestream )
  51 {
  52     while( p_bytestream->p_chain )
  53     {
  54         block_t *p_next;
  55         p_next = p_bytestream->p_chain->p_next;
  56         p_bytestream->p_chain->pf_release( p_bytestream->p_chain );
  57         p_bytestream->p_chain = p_next;
  58     }
  59     p_bytestream->i_offset = 0;
  60     p_bytestream->p_chain = p_bytestream->p_block = NULL;
  61 }
  62
  63 /**
  64  * It flush all data (read and unread) from a block_bytestream_t.
  65  */
  66 static inline void block_BytestreamEmpty( block_bytestream_t *p_bytestream )
  67 {
  68     block_BytestreamRelease( p_bytestream );
  69
  70     *p_bytestream = block_BytestreamInit();
  71 }
  72
  73 /**
  74  * It flushes all already read data from a block_bytestream_t.
  75  */
  76 static inline void block_BytestreamFlush( block_bytestream_t *p_bytestream )
  77 {
  78     while( p_bytestream->p_chain != p_bytestream->p_block )
  79     {
  80         block_t *p_next;
  81         p_next = p_bytestream->p_chain->p_next;
  82         p_bytestream->p_chain->pf_release( p_bytestream->p_chain );
  83         p_bytestream->p_chain = p_next;
  84     }
  85     while( p_bytestream->p_block &&
  86            (p_bytestream->p_block->i_buffer - p_bytestream->i_offset) == 0 )
  87     {
  88         block_t *p_next;
  89         p_next = p_bytestream->p_chain->p_next;
  90         p_bytestream->p_chain->pf_release( p_bytestream->p_chain );
  91         p_bytestream->p_chain = p_bytestream->p_block = p_next;
  92         p_bytestream->i_offset = 0;
  93     }
  94 }
  95
  96 static inline void block_BytestreamPush( block_bytestream_t *p_bytestream,
  97                                          block_t *p_block )
  98 {
  99     block_ChainAppend( &p_bytestream->p_chain, p_block );
 100     if( !p_bytestream->p_block ) p_bytestream->p_block = p_block;
 101 }
 102
 103 LIBVLC_USED
 104 static inline block_t *block_BytestreamPop( block_bytestream_t *p_bytestream )
 105 {
 106     block_t *p_block;
 107
 108     block_BytestreamFlush( p_bytestream );
 109
 110     p_block = p_bytestream->p_block;
 111     if( p_block == NULL )
 112     {
 113         return NULL;
 114     }
 115     else if( !p_block->p_next )
 116     {
 117         p_block->p_buffer += p_bytestream->i_offset;
 118         p_block->i_buffer -= p_bytestream->i_offset;
 119         p_bytestream->i_offset = 0;
 120         p_bytestream->p_chain = p_bytestream->p_block = NULL;
 121         return p_block;
 122     }
 123
 124     while( p_block->p_next && p_block->p_next->p_next )
 125         p_block = p_block->p_next;
 126
 127     {
 128         block_t *p_block_old = p_block;
 129         p_block = p_block->p_next;
 130         p_block_old->p_next = NULL;
 131     }
 132
 133     return p_block;
 134 }
 135
 136 static inline int block_SkipByte( block_bytestream_t *p_bytestream )
 137 {
 138     /* Most common case first */
 139     if( p_bytestream->p_block->i_buffer - p_bytestream->i_offset )
 140     {
 141         p_bytestream->i_offset++;
 142         return VLC_SUCCESS;
 143     }
 144     else
 145     {
 146         block_t *p_block;
 147
 148         /* Less common case which is also slower */
 149         for( p_block = p_bytestream->p_block->p_next;
 150              p_block != NULL; p_block = p_block->p_next )
 151         {
 152             if( p_block->i_buffer )
 153             {
 154                 p_bytestream->i_offset = 1;
 155                 p_bytestream->p_block = p_block;
 156                 return VLC_SUCCESS;
 157             }
 158         }
 159     }
 160
 161     /* Not enough data, bail out */
 162     return VLC_EGENERIC;
 163 }
 164
 165 static inline int block_PeekByte( block_bytestream_t *p_bytestream,
 166                                   uint8_t *p_data )
 167 {
 168     /* Most common case first */
 169     if( p_bytestream->p_block->i_buffer - p_bytestream->i_offset )
 170     {
 171         *p_data = p_bytestream->p_block->p_buffer[p_bytestream->i_offset];
 172         return VLC_SUCCESS;
 173     }
 174     else
 175     {
 176         block_t *p_block;
 177
 178         /* Less common case which is also slower */
 179         for( p_block = p_bytestream->p_block->p_next;
 180              p_block != NULL; p_block = p_block->p_next )
 181         {
 182             if( p_block->i_buffer )
 183             {
 184                 *p_data = p_block->p_buffer[0];
 185                 return VLC_SUCCESS;
 186             }
 187         }
 188     }
 189
 190     /* Not enough data, bail out */
 191     return VLC_EGENERIC;
 192 }
 193
 194 static inline int block_GetByte( block_bytestream_t *p_bytestream,
 195                                  uint8_t *p_data )
 196 {
 197     /* Most common case first */
 198     if( p_bytestream->p_block->i_buffer - p_bytestream->i_offset )
 199     {
 200         *p_data = p_bytestream->p_block->p_buffer[p_bytestream->i_offset];
 201         p_bytestream->i_offset++;
 202         return VLC_SUCCESS;
 203     }
 204     else
 205     {
 206         block_t *p_block;
 207
 208         /* Less common case which is also slower */
 209         for( p_block = p_bytestream->p_block->p_next;
 210              p_block != NULL; p_block = p_block->p_next )
 211         {
 212             if( p_block->i_buffer )
 213             {
 214                 *p_data = p_block->p_buffer[0];
 215                 p_bytestream->i_offset = 1;
 216                 p_bytestream->p_block = p_block;
 217                 return VLC_SUCCESS;
 218             }
 219         }
 220     }
 221
 222     /* Not enough data, bail out */
 223     return VLC_EGENERIC;
 224 }
 225
 226 static inline int block_WaitBytes( block_bytestream_t *p_bytestream,
 227                                    size_t i_data )
 228 {
 229     block_t *p_block;
 230     size_t i_offset, i_copy, i_size;
 231
 232     /* Check we have that much data */
 233     i_offset = p_bytestream->i_offset;
 234     i_size = i_data;
 235     i_copy = 0;
 236     for( p_block = p_bytestream->p_block;
 237          p_block != NULL; p_block = p_block->p_next )
 238     {
 239         i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
 240         i_size -= i_copy;
 241         i_offset = 0;
 242
 243         if( !i_size ) break;
 244     }
 245
 246     if( i_size )
 247     {
 248         /* Not enough data, bail out */
 249         return VLC_EGENERIC;
 250     }
 251     return VLC_SUCCESS;
 252 }
 253
 254 static inline int block_SkipBytes( block_bytestream_t *p_bytestream,
 255                                    size_t i_data )
 256 {
 257     block_t *p_block;
 258     size_t i_offset, i_copy;
 259
 260     /* Check we have that much data */
 261     i_offset = p_bytestream->i_offset;
 262     i_copy = 0;
 263     for( p_block = p_bytestream->p_block;
 264          p_block != NULL; p_block = p_block->p_next )
 265     {
 266         i_copy = __MIN( i_data, p_block->i_buffer - i_offset );
 267         i_data -= i_copy;
 268
 269         if( !i_data ) break;
 270
 271         i_offset = 0;
 272     }
 273
 274     if( i_data )
 275     {
 276         /* Not enough data, bail out */
 277         return VLC_EGENERIC;
 278     }
 279
 280     p_bytestream->p_block = p_block;
 281     p_bytestream->i_offset = i_offset + i_copy;
 282     return VLC_SUCCESS;
 283 }
 284
 285 static inline int block_PeekBytes( block_bytestream_t *p_bytestream,
 286                                    uint8_t *p_data, size_t i_data )
 287 {
 288     block_t *p_block;
 289     size_t i_offset, i_copy, i_size;
 290
 291     /* Check we have that much data */
 292     i_offset = p_bytestream->i_offset;
 293     i_size = i_data;
 294     i_copy = 0;
 295     for( p_block = p_bytestream->p_block;
 296          p_block != NULL; p_block = p_block->p_next )
 297     {
 298         i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
 299         i_size -= i_copy;
 300         i_offset = 0;
 301
 302         if( !i_size ) break;
 303     }
 304
 305     if( i_size )
 306     {
 307         /* Not enough data, bail out */
 308         return VLC_EGENERIC;
 309     }
 310
 311     /* Copy the data */
 312     i_offset = p_bytestream->i_offset;
 313     i_size = i_data;
 314     i_copy = 0;
 315     for( p_block = p_bytestream->p_block;
 316          p_block != NULL; p_block = p_block->p_next )
 317     {
 318         i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
 319         i_size -= i_copy;
 320
 321         if( i_copy )
 322         {
 323             memcpy( p_data, p_block->p_buffer + i_offset, i_copy );
 324             p_data += i_copy;
 325         }
 326
 327         i_offset = 0;
 328
 329         if( !i_size ) break;
 330     }
 331
 332     return VLC_SUCCESS;
 333 }
 334
 335 static inline int block_GetBytes( block_bytestream_t *p_bytestream,
 336                                   uint8_t *p_data, size_t i_data )
 337 {
 338     block_t *p_block;
 339     size_t i_offset, i_copy, i_size;
 340
 341     /* Check we have that much data */
 342     i_offset = p_bytestream->i_offset;
 343     i_size = i_data;
 344     i_copy = 0;
 345     for( p_block = p_bytestream->p_block;
 346          p_block != NULL; p_block = p_block->p_next )
 347     {
 348         i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
 349         i_size -= i_copy;
 350         i_offset = 0;
 351
 352         if( !i_size ) break;
 353     }
 354
 355     if( i_size )
 356     {
 357         /* Not enough data, bail out */
 358         return VLC_EGENERIC;
 359     }
 360
 361     /* Copy the data */
 362     i_offset = p_bytestream->i_offset;
 363     i_size = i_data;
 364     i_copy = 0;
 365     for( p_block = p_bytestream->p_block;
 366          p_block != NULL; p_block = p_block->p_next )
 367     {
 368         i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
 369         i_size -= i_copy;
 370
 371         if( i_copy )
 372         {
 373             memcpy( p_data, p_block->p_buffer + i_offset, i_copy );
 374             p_data += i_copy;
 375         }
 376
 377         if( !i_size ) break;
 378
 379         i_offset = 0;
 380     }
 381
 382     /* No buffer given, just skip the data */
 383     p_bytestream->p_block = p_block;
 384     p_bytestream->i_offset = i_offset + i_copy;
 385
 386     return VLC_SUCCESS;
 387 }
 388
 389 static inline int block_PeekOffsetBytes( block_bytestream_t *p_bytestream,
 390     size_t i_peek_offset, uint8_t *p_data, size_t i_data )
 391 {
 392     block_t *p_block;
 393     size_t i_offset, i_copy, i_size;
 394
 395     /* Check we have that much data */
 396     i_offset = p_bytestream->i_offset;
 397     i_size = i_data + i_peek_offset;
 398     i_copy = 0;
 399     for( p_block = p_bytestream->p_block;
 400          p_block != NULL; p_block = p_block->p_next )
 401     {
 402         i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
 403         i_size -= i_copy;
 404         i_offset = 0;
 405
 406         if( !i_size ) break;
 407     }
 408
 409     if( i_size )
 410     {
 411         /* Not enough data, bail out */
 412         return VLC_EGENERIC;
 413     }
 414
 415     /* Find the right place */
 416     i_offset = p_bytestream->i_offset;
 417     i_size = i_peek_offset;
 418     i_copy = 0;
 419     for( p_block = p_bytestream->p_block;
 420          p_block != NULL; p_block = p_block->p_next )
 421     {
 422         i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
 423         i_size -= i_copy;
 424
 425         if( !i_size ) break;
 426
 427         i_offset = 0;
 428     }
 429
 430     /* Copy the data */
 431     i_offset += i_copy;
 432     i_size = i_data;
 433     i_copy = 0;
 434     for( ; p_block != NULL; p_block = p_block->p_next )
 435     {
 436         i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
 437         i_size -= i_copy;
 438
 439         if( i_copy )
 440         {
 441             memcpy( p_data, p_block->p_buffer + i_offset, i_copy );
 442             p_data += i_copy;
 443         }
 444
 445         i_offset = 0;
 446
 447         if( !i_size ) break;
 448     }
 449
 450     return VLC_SUCCESS;
 451 }
 452
 453 static inline int block_FindStartcodeFromOffset(
 454     block_bytestream_t *p_bytestream, size_t *pi_offset,
 455     const uint8_t *p_startcode, int i_startcode_length )
 456 {
 457     block_t *p_block, *p_block_backup = 0;
 458     int i_size = 0;
 459     size_t i_offset, i_offset_backup = 0;
 460     int i_caller_offset_backup = 0, i_match;
 461
 462     /* Find the right place */
 463     i_size = *pi_offset + p_bytestream->i_offset;
 464     for( p_block = p_bytestream->p_block;
 465          p_block != NULL; p_block = p_block->p_next )
 466     {
 467         i_size -= p_block->i_buffer;
 468         if( i_size < 0 ) break;
 469     }
 470
 471     if( i_size >= 0 )
 472     {
 473         /* Not enough data, bail out */
 474         return VLC_EGENERIC;
 475     }
 476
 477     /* Begin the search.
 478      * We first look for an occurrence of the 1st startcode byte and
 479      * if found, we do a more thorough check. */
 480     i_size += p_block->i_buffer;
 481     *pi_offset -= i_size;
 482     i_match = 0;
 483     for( ; p_block != NULL; p_block = p_block->p_next )
 484     {
 485         for( i_offset = i_size; i_offset < p_block->i_buffer; i_offset++ )
 486         {
 487             if( p_block->p_buffer[i_offset] == p_startcode[i_match] )
 488             {
 489                 if( !i_match )
 490                 {
 491                     p_block_backup = p_block;
 492                     i_offset_backup = i_offset;
 493                     i_caller_offset_backup = *pi_offset;
 494                 }
 495
 496                 if( i_match + 1 == i_startcode_length )
 497                 {
 498                     /* We have it */
 499                     *pi_offset += i_offset - i_match;
 500                     return VLC_SUCCESS;
 501                 }
 502
 503                 i_match++;
 504             }
 505             else if ( i_match )
 506             {
 507                 /* False positive */
 508                 p_block = p_block_backup;
 509                 i_offset = i_offset_backup;
 510                 *pi_offset = i_caller_offset_backup;
 511                 i_match = 0;
 512             }
 513
 514         }
 515         i_size = 0;
 516         *pi_offset += i_offset;
 517     }
 518
 519     *pi_offset -= i_match;
 520     return VLC_EGENERIC;
 521 }
 522
 523 #endif /* VLC_BLOCK_HELPER_H */