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 static inline void block_BytestreamFlush( block_bytestream_t *p_bytestream )
  64 {
  65     while( p_bytestream->p_chain != p_bytestream->p_block )
  66     {
  67         block_t *p_next;
  68         p_next = p_bytestream->p_chain->p_next;
  69         p_bytestream->p_chain->pf_release( p_bytestream->p_chain );
  70         p_bytestream->p_chain = p_next;
  71     }
  72     while( p_bytestream->p_block &&
  73            (p_bytestream->p_block->i_buffer - p_bytestream->i_offset) == 0 )
  74     {
  75         block_t *p_next;
  76         p_next = p_bytestream->p_chain->p_next;
  77         p_bytestream->p_chain->pf_release( p_bytestream->p_chain );
  78         p_bytestream->p_chain = p_bytestream->p_block = p_next;
  79         p_bytestream->i_offset = 0;
  80     }
  81 }
  82
  83 static inline void block_BytestreamPush( block_bytestream_t *p_bytestream,
  84                                          block_t *p_block )
  85 {
  86     block_ChainAppend( &p_bytestream->p_chain, p_block );
  87     if( !p_bytestream->p_block ) p_bytestream->p_block = p_block;
  88 }
  89
  90 static inline block_t *block_BytestreamPop( block_bytestream_t *p_bytestream )
  91 {
  92     block_t *p_block;
  93
  94     block_BytestreamFlush( p_bytestream );
  95
  96     p_block = p_bytestream->p_block;
  97     if( p_block == NULL )
  98     {
  99         return NULL;
 100     }
 101     else if( !p_block->p_next )
 102     {
 103         p_block->p_buffer += p_bytestream->i_offset;
 104         p_block->i_buffer -= p_bytestream->i_offset;
 105         p_bytestream->i_offset = 0;
 106         p_bytestream->p_chain = p_bytestream->p_block = NULL;
 107         return p_block;
 108     }
 109
 110     while( p_block->p_next && p_block->p_next->p_next )
 111         p_block = p_block->p_next;
 112
 113     {
 114         block_t *p_block_old = p_block;
 115         p_block = p_block->p_next;
 116         p_block_old->p_next = NULL;
 117     }
 118
 119     return p_block;
 120 }
 121
 122 static inline int block_SkipByte( block_bytestream_t *p_bytestream )
 123 {
 124     /* Most common case first */
 125     if( p_bytestream->p_block->i_buffer - p_bytestream->i_offset )
 126     {
 127         p_bytestream->i_offset++;
 128         return VLC_SUCCESS;
 129     }
 130     else
 131     {
 132         block_t *p_block;
 133
 134         /* Less common case which is also slower */
 135         for( p_block = p_bytestream->p_block->p_next;
 136              p_block != NULL; p_block = p_block->p_next )
 137         {
 138             if( p_block->i_buffer )
 139             {
 140                 p_bytestream->i_offset = 1;
 141                 p_bytestream->p_block = p_block;
 142                 return VLC_SUCCESS;
 143             }
 144         }
 145     }
 146
 147     /* Not enough data, bail out */
 148     return VLC_EGENERIC;
 149 }
 150
 151 static inline int block_PeekByte( block_bytestream_t *p_bytestream,
 152                                   uint8_t *p_data )
 153 {
 154     /* Most common case first */
 155     if( p_bytestream->p_block->i_buffer - p_bytestream->i_offset )
 156     {
 157         *p_data = p_bytestream->p_block->p_buffer[p_bytestream->i_offset];
 158         return VLC_SUCCESS;
 159     }
 160     else
 161     {
 162         block_t *p_block;
 163
 164         /* Less common case which is also slower */
 165         for( p_block = p_bytestream->p_block->p_next;
 166              p_block != NULL; p_block = p_block->p_next )
 167         {
 168             if( p_block->i_buffer )
 169             {
 170                 *p_data = p_block->p_buffer[0];
 171                 return VLC_SUCCESS;
 172             }
 173         }
 174     }
 175
 176     /* Not enough data, bail out */
 177     return VLC_EGENERIC;
 178 }
 179
 180 static inline int block_GetByte( block_bytestream_t *p_bytestream,
 181                                  uint8_t *p_data )
 182 {
 183     /* Most common case first */
 184     if( p_bytestream->p_block->i_buffer - p_bytestream->i_offset )
 185     {
 186         *p_data = p_bytestream->p_block->p_buffer[p_bytestream->i_offset];
 187         p_bytestream->i_offset++;
 188         return VLC_SUCCESS;
 189     }
 190     else
 191     {
 192         block_t *p_block;
 193
 194         /* Less common case which is also slower */
 195         for( p_block = p_bytestream->p_block->p_next;
 196              p_block != NULL; p_block = p_block->p_next )
 197         {
 198             if( p_block->i_buffer )
 199             {
 200                 *p_data = p_block->p_buffer[0];
 201                 p_bytestream->i_offset = 1;
 202                 p_bytestream->p_block = p_block;
 203                 return VLC_SUCCESS;
 204             }
 205         }
 206     }
 207
 208     /* Not enough data, bail out */
 209     return VLC_EGENERIC;
 210 }
 211
 212 static inline int block_WaitBytes( block_bytestream_t *p_bytestream,
 213                                    size_t i_data )
 214 {
 215     block_t *p_block;
 216     size_t i_offset, i_copy, i_size;
 217
 218     /* Check we have that much data */
 219     i_offset = p_bytestream->i_offset;
 220     i_size = i_data;
 221     i_copy = 0;
 222     for( p_block = p_bytestream->p_block;
 223          p_block != NULL; p_block = p_block->p_next )
 224     {
 225         i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
 226         i_size -= i_copy;
 227         i_offset = 0;
 228
 229         if( !i_size ) break;
 230     }
 231
 232     if( i_size )
 233     {
 234         /* Not enough data, bail out */
 235         return VLC_EGENERIC;
 236     }
 237     return VLC_SUCCESS;
 238 }
 239
 240 static inline int block_SkipBytes( block_bytestream_t *p_bytestream,
 241                                    size_t i_data )
 242 {
 243     block_t *p_block;
 244     size_t i_offset, i_copy;
 245
 246     /* Check we have that much data */
 247     i_offset = p_bytestream->i_offset;
 248     i_copy = 0;
 249     for( p_block = p_bytestream->p_block;
 250          p_block != NULL; p_block = p_block->p_next )
 251     {
 252         i_copy = __MIN( i_data, p_block->i_buffer - i_offset );
 253         i_data -= i_copy;
 254
 255         if( !i_data ) break;
 256
 257         i_offset = 0;
 258     }
 259
 260     if( i_data )
 261     {
 262         /* Not enough data, bail out */
 263         return VLC_EGENERIC;
 264     }
 265
 266     p_bytestream->p_block = p_block;
 267     p_bytestream->i_offset = i_offset + i_copy;
 268     return VLC_SUCCESS;
 269 }
 270
 271 static inline int block_PeekBytes( block_bytestream_t *p_bytestream,
 272                                    uint8_t *p_data, size_t i_data )
 273 {
 274     block_t *p_block;
 275     size_t i_offset, i_copy, i_size;
 276
 277     /* Check we have that much data */
 278     i_offset = p_bytestream->i_offset;
 279     i_size = i_data;
 280     i_copy = 0;
 281     for( p_block = p_bytestream->p_block;
 282          p_block != NULL; p_block = p_block->p_next )
 283     {
 284         i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
 285         i_size -= i_copy;
 286         i_offset = 0;
 287
 288         if( !i_size ) break;
 289     }
 290
 291     if( i_size )
 292     {
 293         /* Not enough data, bail out */
 294         return VLC_EGENERIC;
 295     }
 296
 297     /* Copy the data */
 298     i_offset = p_bytestream->i_offset;
 299     i_size = i_data;
 300     i_copy = 0;
 301     for( p_block = p_bytestream->p_block;
 302          p_block != NULL; p_block = p_block->p_next )
 303     {
 304         i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
 305         i_size -= i_copy;
 306
 307         if( i_copy )
 308         {
 309             memcpy( p_data, p_block->p_buffer + i_offset, i_copy );
 310             p_data += i_copy;
 311         }
 312
 313         i_offset = 0;
 314
 315         if( !i_size ) break;
 316     }
 317
 318     return VLC_SUCCESS;
 319 }
 320
 321 static inline int block_GetBytes( block_bytestream_t *p_bytestream,
 322                                   uint8_t *p_data, size_t i_data )
 323 {
 324     block_t *p_block;
 325     size_t i_offset, i_copy, i_size;
 326
 327     /* Check we have that much data */
 328     i_offset = p_bytestream->i_offset;
 329     i_size = i_data;
 330     i_copy = 0;
 331     for( p_block = p_bytestream->p_block;
 332          p_block != NULL; p_block = p_block->p_next )
 333     {
 334         i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
 335         i_size -= i_copy;
 336         i_offset = 0;
 337
 338         if( !i_size ) break;
 339     }
 340
 341     if( i_size )
 342     {
 343         /* Not enough data, bail out */
 344         return VLC_EGENERIC;
 345     }
 346
 347     /* Copy the data */
 348     i_offset = p_bytestream->i_offset;
 349     i_size = i_data;
 350     i_copy = 0;
 351     for( p_block = p_bytestream->p_block;
 352          p_block != NULL; p_block = p_block->p_next )
 353     {
 354         i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
 355         i_size -= i_copy;
 356
 357         if( i_copy )
 358         {
 359             memcpy( p_data, p_block->p_buffer + i_offset, i_copy );
 360             p_data += i_copy;
 361         }
 362
 363         if( !i_size ) break;
 364
 365         i_offset = 0;
 366     }
 367
 368     /* No buffer given, just skip the data */
 369     p_bytestream->p_block = p_block;
 370     p_bytestream->i_offset = i_offset + i_copy;
 371
 372     return VLC_SUCCESS;
 373 }
 374
 375 static inline int block_PeekOffsetBytes( block_bytestream_t *p_bytestream,
 376     size_t i_peek_offset, uint8_t *p_data, size_t i_data )
 377 {
 378     block_t *p_block;
 379     size_t i_offset, i_copy, i_size;
 380
 381     /* Check we have that much data */
 382     i_offset = p_bytestream->i_offset;
 383     i_size = i_data + i_peek_offset;
 384     i_copy = 0;
 385     for( p_block = p_bytestream->p_block;
 386          p_block != NULL; p_block = p_block->p_next )
 387     {
 388         i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
 389         i_size -= i_copy;
 390         i_offset = 0;
 391
 392         if( !i_size ) break;
 393     }
 394
 395     if( i_size )
 396     {
 397         /* Not enough data, bail out */
 398         return VLC_EGENERIC;
 399     }
 400
 401     /* Find the right place */
 402     i_offset = p_bytestream->i_offset;
 403     i_size = i_peek_offset;
 404     i_copy = 0;
 405     for( p_block = p_bytestream->p_block;
 406          p_block != NULL; p_block = p_block->p_next )
 407     {
 408         i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
 409         i_size -= i_copy;
 410
 411         if( !i_size ) break;
 412
 413         i_offset = 0;
 414     }
 415
 416     /* Copy the data */
 417     i_offset += i_copy;
 418     i_size = i_data;
 419     i_copy = 0;
 420     for( ; 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_copy )
 426         {
 427             memcpy( p_data, p_block->p_buffer + i_offset, i_copy );
 428             p_data += i_copy;
 429         }
 430
 431         i_offset = 0;
 432
 433         if( !i_size ) break;
 434     }
 435
 436     return VLC_SUCCESS;
 437 }
 438
 439 static inline int block_FindStartcodeFromOffset(
 440     block_bytestream_t *p_bytestream, size_t *pi_offset,
 441     uint8_t *p_startcode, int i_startcode_length )
 442 {
 443     block_t *p_block, *p_block_backup = 0;
 444     int i_size = 0;
 445     size_t i_offset, i_offset_backup = 0;
 446     int i_caller_offset_backup = 0, i_match;
 447
 448     /* Find the right place */
 449     i_size = *pi_offset + p_bytestream->i_offset;
 450     for( p_block = p_bytestream->p_block;
 451          p_block != NULL; p_block = p_block->p_next )
 452     {
 453         i_size -= p_block->i_buffer;
 454         if( i_size < 0 ) break;
 455     }
 456
 457     if( i_size >= 0 )
 458     {
 459         /* Not enough data, bail out */
 460         return VLC_EGENERIC;
 461     }
 462
 463     /* Begin the search.
 464      * We first look for an occurrence of the 1st startcode byte and
 465      * if found, we do a more thorough check. */
 466     i_size += p_block->i_buffer;
 467     *pi_offset -= i_size;
 468     i_match = 0;
 469     for( ; p_block != NULL; p_block = p_block->p_next )
 470     {
 471         for( i_offset = i_size; i_offset < p_block->i_buffer; i_offset++ )
 472         {
 473             if( p_block->p_buffer[i_offset] == p_startcode[i_match] )
 474             {
 475                 if( !i_match )
 476                 {
 477                     p_block_backup = p_block;
 478                     i_offset_backup = i_offset;
 479                     i_caller_offset_backup = *pi_offset;
 480                 }
 481
 482                 if( i_match + 1 == i_startcode_length )
 483                 {
 484                     /* We have it */
 485                     *pi_offset += i_offset - i_match;
 486                     return VLC_SUCCESS;
 487                 }
 488
 489                 i_match++;
 490             }
 491             else if ( i_match )
 492             {
 493                 /* False positive */
 494                 p_block = p_block_backup;
 495                 i_offset = i_offset_backup;
 496                 *pi_offset = i_caller_offset_backup;
 497                 i_match = 0;
 498             }
 499
 500         }
 501         i_size = 0;
 502         *pi_offset += i_offset;
 503     }
 504
 505     *pi_offset -= i_match;
 506     return VLC_EGENERIC;
 507 }
 508
 509 #endif /* VLC_BLOCK_HELPER_H */