1 /*****************************************************************************
2 * vlc_block_helper.h: Helper functions for data blocks management.
3 *****************************************************************************
4 * Copyright (C) 2003 the VideoLAN team
7 * Authors: Gildas Bazin <gbazin@netcourrier.com>
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.
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.
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 *****************************************************************************/
24 #ifndef VLC_BLOCK_HELPER_H
25 #define VLC_BLOCK_HELPER_H 1
27 #include <vlc_block.h>
29 typedef struct block_bytestream_t
37 /*****************************************************************************
38 * block_bytestream_t management
39 *****************************************************************************/
40 static inline block_bytestream_t block_BytestreamInit( void )
42 block_bytestream_t bytestream;
44 bytestream.i_offset = 0;
45 bytestream.p_chain = bytestream.p_block = NULL;
50 static inline void block_BytestreamRelease( block_bytestream_t *p_bytestream )
52 while( p_bytestream->p_chain )
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;
59 p_bytestream->i_offset = 0;
60 p_bytestream->p_chain = p_bytestream->p_block = NULL;
64 * It flush all data (read and unread) from a block_bytestream_t.
66 static inline void block_BytestreamEmpty( block_bytestream_t *p_bytestream )
68 block_BytestreamRelease( p_bytestream );
70 *p_bytestream = block_BytestreamInit();
74 * It flushes all already read data from a block_bytestream_t.
76 static inline void block_BytestreamFlush( block_bytestream_t *p_bytestream )
78 while( p_bytestream->p_chain != p_bytestream->p_block )
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;
85 while( p_bytestream->p_block &&
86 (p_bytestream->p_block->i_buffer - p_bytestream->i_offset) == 0 )
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;
96 static inline void block_BytestreamPush( block_bytestream_t *p_bytestream,
99 block_ChainAppend( &p_bytestream->p_chain, p_block );
100 if( !p_bytestream->p_block ) p_bytestream->p_block = p_block;
104 static inline block_t *block_BytestreamPop( block_bytestream_t *p_bytestream )
108 block_BytestreamFlush( p_bytestream );
110 p_block = p_bytestream->p_block;
111 if( p_block == NULL )
115 else if( !p_block->p_next )
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;
124 while( p_block->p_next && p_block->p_next->p_next )
125 p_block = p_block->p_next;
128 block_t *p_block_old = p_block;
129 p_block = p_block->p_next;
130 p_block_old->p_next = NULL;
136 static inline int block_SkipByte( block_bytestream_t *p_bytestream )
138 /* Most common case first */
139 if( p_bytestream->p_block->i_buffer - p_bytestream->i_offset )
141 p_bytestream->i_offset++;
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 )
152 if( p_block->i_buffer )
154 p_bytestream->i_offset = 1;
155 p_bytestream->p_block = p_block;
161 /* Not enough data, bail out */
165 static inline int block_PeekByte( block_bytestream_t *p_bytestream,
168 /* Most common case first */
169 if( p_bytestream->p_block->i_buffer - p_bytestream->i_offset )
171 *p_data = p_bytestream->p_block->p_buffer[p_bytestream->i_offset];
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 )
182 if( p_block->i_buffer )
184 *p_data = p_block->p_buffer[0];
190 /* Not enough data, bail out */
194 static inline int block_GetByte( block_bytestream_t *p_bytestream,
197 /* Most common case first */
198 if( p_bytestream->p_block->i_buffer - p_bytestream->i_offset )
200 *p_data = p_bytestream->p_block->p_buffer[p_bytestream->i_offset];
201 p_bytestream->i_offset++;
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 )
212 if( p_block->i_buffer )
214 *p_data = p_block->p_buffer[0];
215 p_bytestream->i_offset = 1;
216 p_bytestream->p_block = p_block;
222 /* Not enough data, bail out */
226 static inline int block_WaitBytes( block_bytestream_t *p_bytestream,
230 size_t i_offset, i_copy, i_size;
232 /* Check we have that much data */
233 i_offset = p_bytestream->i_offset;
236 for( p_block = p_bytestream->p_block;
237 p_block != NULL; p_block = p_block->p_next )
239 i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
248 /* Not enough data, bail out */
254 static inline int block_SkipBytes( block_bytestream_t *p_bytestream,
258 size_t i_offset, i_copy;
260 /* Check we have that much data */
261 i_offset = p_bytestream->i_offset;
263 for( p_block = p_bytestream->p_block;
264 p_block != NULL; p_block = p_block->p_next )
266 i_copy = __MIN( i_data, p_block->i_buffer - i_offset );
276 /* Not enough data, bail out */
280 p_bytestream->p_block = p_block;
281 p_bytestream->i_offset = i_offset + i_copy;
285 static inline int block_PeekBytes( block_bytestream_t *p_bytestream,
286 uint8_t *p_data, size_t i_data )
289 size_t i_offset, i_copy, i_size;
291 /* Check we have that much data */
292 i_offset = p_bytestream->i_offset;
295 for( p_block = p_bytestream->p_block;
296 p_block != NULL; p_block = p_block->p_next )
298 i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
307 /* Not enough data, bail out */
312 i_offset = p_bytestream->i_offset;
315 for( p_block = p_bytestream->p_block;
316 p_block != NULL; p_block = p_block->p_next )
318 i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
323 memcpy( p_data, p_block->p_buffer + i_offset, i_copy );
335 static inline int block_GetBytes( block_bytestream_t *p_bytestream,
336 uint8_t *p_data, size_t i_data )
339 size_t i_offset, i_copy, i_size;
341 /* Check we have that much data */
342 i_offset = p_bytestream->i_offset;
345 for( p_block = p_bytestream->p_block;
346 p_block != NULL; p_block = p_block->p_next )
348 i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
357 /* Not enough data, bail out */
362 i_offset = p_bytestream->i_offset;
365 for( p_block = p_bytestream->p_block;
366 p_block != NULL; p_block = p_block->p_next )
368 i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
373 memcpy( p_data, p_block->p_buffer + i_offset, i_copy );
382 /* No buffer given, just skip the data */
383 p_bytestream->p_block = p_block;
384 p_bytestream->i_offset = i_offset + i_copy;
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 )
393 size_t i_offset, i_copy, i_size;
395 /* Check we have that much data */
396 i_offset = p_bytestream->i_offset;
397 i_size = i_data + i_peek_offset;
399 for( p_block = p_bytestream->p_block;
400 p_block != NULL; p_block = p_block->p_next )
402 i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
411 /* Not enough data, bail out */
415 /* Find the right place */
416 i_offset = p_bytestream->i_offset;
417 i_size = i_peek_offset;
419 for( p_block = p_bytestream->p_block;
420 p_block != NULL; p_block = p_block->p_next )
422 i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
434 for( ; p_block != NULL; p_block = p_block->p_next )
436 i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
441 memcpy( p_data, p_block->p_buffer + i_offset, i_copy );
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 )
457 block_t *p_block, *p_block_backup = 0;
459 size_t i_offset, i_offset_backup = 0;
460 int i_caller_offset_backup = 0, i_match;
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 )
467 i_size -= p_block->i_buffer;
468 if( i_size < 0 ) break;
473 /* Not enough data, bail out */
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;
483 for( ; p_block != NULL; p_block = p_block->p_next )
485 for( i_offset = i_size; i_offset < p_block->i_buffer; i_offset++ )
487 if( p_block->p_buffer[i_offset] == p_startcode[i_match] )
491 p_block_backup = p_block;
492 i_offset_backup = i_offset;
493 i_caller_offset_backup = *pi_offset;
496 if( i_match + 1 == i_startcode_length )
499 *pi_offset += i_offset - i_match;
508 p_block = p_block_backup;
509 i_offset = i_offset_backup;
510 *pi_offset = i_caller_offset_backup;
516 *pi_offset += i_offset;
519 *pi_offset -= i_match;
523 #endif /* VLC_BLOCK_HELPER_H */