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;
63 static inline void block_BytestreamFlush( block_bytestream_t *p_bytestream )
65 while( p_bytestream->p_chain != p_bytestream->p_block )
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;
72 while( p_bytestream->p_block &&
73 (p_bytestream->p_block->i_buffer - p_bytestream->i_offset) == 0 )
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;
83 static inline void block_BytestreamPush( block_bytestream_t *p_bytestream,
86 block_ChainAppend( &p_bytestream->p_chain, p_block );
87 if( !p_bytestream->p_block ) p_bytestream->p_block = p_block;
91 static inline block_t *block_BytestreamPop( block_bytestream_t *p_bytestream )
95 block_BytestreamFlush( p_bytestream );
97 p_block = p_bytestream->p_block;
102 else if( !p_block->p_next )
104 p_block->p_buffer += p_bytestream->i_offset;
105 p_block->i_buffer -= p_bytestream->i_offset;
106 p_bytestream->i_offset = 0;
107 p_bytestream->p_chain = p_bytestream->p_block = NULL;
111 while( p_block->p_next && p_block->p_next->p_next )
112 p_block = p_block->p_next;
115 block_t *p_block_old = p_block;
116 p_block = p_block->p_next;
117 p_block_old->p_next = NULL;
123 static inline int block_SkipByte( block_bytestream_t *p_bytestream )
125 /* Most common case first */
126 if( p_bytestream->p_block->i_buffer - p_bytestream->i_offset )
128 p_bytestream->i_offset++;
135 /* Less common case which is also slower */
136 for( p_block = p_bytestream->p_block->p_next;
137 p_block != NULL; p_block = p_block->p_next )
139 if( p_block->i_buffer )
141 p_bytestream->i_offset = 1;
142 p_bytestream->p_block = p_block;
148 /* Not enough data, bail out */
152 static inline int block_PeekByte( block_bytestream_t *p_bytestream,
155 /* Most common case first */
156 if( p_bytestream->p_block->i_buffer - p_bytestream->i_offset )
158 *p_data = p_bytestream->p_block->p_buffer[p_bytestream->i_offset];
165 /* Less common case which is also slower */
166 for( p_block = p_bytestream->p_block->p_next;
167 p_block != NULL; p_block = p_block->p_next )
169 if( p_block->i_buffer )
171 *p_data = p_block->p_buffer[0];
177 /* Not enough data, bail out */
181 static inline int block_GetByte( block_bytestream_t *p_bytestream,
184 /* Most common case first */
185 if( p_bytestream->p_block->i_buffer - p_bytestream->i_offset )
187 *p_data = p_bytestream->p_block->p_buffer[p_bytestream->i_offset];
188 p_bytestream->i_offset++;
195 /* Less common case which is also slower */
196 for( p_block = p_bytestream->p_block->p_next;
197 p_block != NULL; p_block = p_block->p_next )
199 if( p_block->i_buffer )
201 *p_data = p_block->p_buffer[0];
202 p_bytestream->i_offset = 1;
203 p_bytestream->p_block = p_block;
209 /* Not enough data, bail out */
213 static inline int block_WaitBytes( block_bytestream_t *p_bytestream,
217 size_t i_offset, i_copy, i_size;
219 /* Check we have that much data */
220 i_offset = p_bytestream->i_offset;
223 for( p_block = p_bytestream->p_block;
224 p_block != NULL; p_block = p_block->p_next )
226 i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
235 /* Not enough data, bail out */
241 static inline int block_SkipBytes( block_bytestream_t *p_bytestream,
245 size_t i_offset, i_copy;
247 /* Check we have that much data */
248 i_offset = p_bytestream->i_offset;
250 for( p_block = p_bytestream->p_block;
251 p_block != NULL; p_block = p_block->p_next )
253 i_copy = __MIN( i_data, p_block->i_buffer - i_offset );
263 /* Not enough data, bail out */
267 p_bytestream->p_block = p_block;
268 p_bytestream->i_offset = i_offset + i_copy;
272 static inline int block_PeekBytes( block_bytestream_t *p_bytestream,
273 uint8_t *p_data, size_t i_data )
276 size_t i_offset, i_copy, i_size;
278 /* Check we have that much data */
279 i_offset = p_bytestream->i_offset;
282 for( p_block = p_bytestream->p_block;
283 p_block != NULL; p_block = p_block->p_next )
285 i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
294 /* Not enough data, bail out */
299 i_offset = p_bytestream->i_offset;
302 for( p_block = p_bytestream->p_block;
303 p_block != NULL; p_block = p_block->p_next )
305 i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
310 memcpy( p_data, p_block->p_buffer + i_offset, i_copy );
322 static inline int block_GetBytes( block_bytestream_t *p_bytestream,
323 uint8_t *p_data, size_t i_data )
326 size_t i_offset, i_copy, i_size;
328 /* Check we have that much data */
329 i_offset = p_bytestream->i_offset;
332 for( p_block = p_bytestream->p_block;
333 p_block != NULL; p_block = p_block->p_next )
335 i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
344 /* Not enough data, bail out */
349 i_offset = p_bytestream->i_offset;
352 for( p_block = p_bytestream->p_block;
353 p_block != NULL; p_block = p_block->p_next )
355 i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
360 memcpy( p_data, p_block->p_buffer + i_offset, i_copy );
369 /* No buffer given, just skip the data */
370 p_bytestream->p_block = p_block;
371 p_bytestream->i_offset = i_offset + i_copy;
376 static inline int block_PeekOffsetBytes( block_bytestream_t *p_bytestream,
377 size_t i_peek_offset, uint8_t *p_data, size_t i_data )
380 size_t i_offset, i_copy, i_size;
382 /* Check we have that much data */
383 i_offset = p_bytestream->i_offset;
384 i_size = i_data + i_peek_offset;
386 for( p_block = p_bytestream->p_block;
387 p_block != NULL; p_block = p_block->p_next )
389 i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
398 /* Not enough data, bail out */
402 /* Find the right place */
403 i_offset = p_bytestream->i_offset;
404 i_size = i_peek_offset;
406 for( p_block = p_bytestream->p_block;
407 p_block != NULL; p_block = p_block->p_next )
409 i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
421 for( ; p_block != NULL; p_block = p_block->p_next )
423 i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
428 memcpy( p_data, p_block->p_buffer + i_offset, i_copy );
440 static inline int block_FindStartcodeFromOffset(
441 block_bytestream_t *p_bytestream, size_t *pi_offset,
442 const uint8_t *p_startcode, int i_startcode_length )
444 block_t *p_block, *p_block_backup = 0;
446 size_t i_offset, i_offset_backup = 0;
447 int i_caller_offset_backup = 0, i_match;
449 /* Find the right place */
450 i_size = *pi_offset + p_bytestream->i_offset;
451 for( p_block = p_bytestream->p_block;
452 p_block != NULL; p_block = p_block->p_next )
454 i_size -= p_block->i_buffer;
455 if( i_size < 0 ) break;
460 /* Not enough data, bail out */
465 * We first look for an occurrence of the 1st startcode byte and
466 * if found, we do a more thorough check. */
467 i_size += p_block->i_buffer;
468 *pi_offset -= i_size;
470 for( ; p_block != NULL; p_block = p_block->p_next )
472 for( i_offset = i_size; i_offset < p_block->i_buffer; i_offset++ )
474 if( p_block->p_buffer[i_offset] == p_startcode[i_match] )
478 p_block_backup = p_block;
479 i_offset_backup = i_offset;
480 i_caller_offset_backup = *pi_offset;
483 if( i_match + 1 == i_startcode_length )
486 *pi_offset += i_offset - i_match;
495 p_block = p_block_backup;
496 i_offset = i_offset_backup;
497 *pi_offset = i_caller_offset_backup;
503 *pi_offset += i_offset;
506 *pi_offset -= i_match;
510 #endif /* VLC_BLOCK_HELPER_H */