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
31 block_t *p_chain; /**< byte stream head block */
32 block_t *p_block; /**< byte stream read pointer block */
33 size_t i_offset; /**< byte stream read pointer offset within block */
34 /* TODO? add tail pointer for faster push? */
37 /*****************************************************************************
38 * block_bytestream_t management
39 *****************************************************************************/
40 static inline void block_BytestreamInit( block_bytestream_t *p_bytestream )
42 p_bytestream->p_chain = p_bytestream->p_block = NULL;
43 p_bytestream->i_offset = 0;
46 static inline void block_BytestreamRelease( block_bytestream_t *p_bytestream )
48 for( block_t *block = p_bytestream->p_chain; block != NULL; )
50 block_t *p_next = block->p_next;
52 block_Release( block );
58 * It flush all data (read and unread) from a block_bytestream_t.
60 static inline void block_BytestreamEmpty( block_bytestream_t *p_bytestream )
62 block_BytestreamRelease( p_bytestream );
63 block_BytestreamInit( p_bytestream );
67 * It flushes all already read data from a block_bytestream_t.
69 static inline void block_BytestreamFlush( block_bytestream_t *p_bytestream )
71 block_t *block = p_bytestream->p_chain;
73 while( block != p_bytestream->p_block )
75 block_t *p_next = block->p_next;
77 block_Release( block );
81 while( block != NULL && block->i_buffer == p_bytestream->i_offset )
83 block_t *p_next = block->p_next;
85 block_Release( block );
87 p_bytestream->i_offset = 0;
90 p_bytestream->p_chain = p_bytestream->p_block = block;
93 static inline void block_BytestreamPush( block_bytestream_t *p_bytestream,
96 block_ChainAppend( &p_bytestream->p_chain, p_block );
97 if( !p_bytestream->p_block ) p_bytestream->p_block = p_block;
101 static inline block_t *block_BytestreamPop( block_bytestream_t *p_bytestream )
105 block_BytestreamFlush( p_bytestream );
107 p_block = p_bytestream->p_block;
108 if( p_block == NULL )
112 else if( !p_block->p_next )
114 p_block->p_buffer += p_bytestream->i_offset;
115 p_block->i_buffer -= p_bytestream->i_offset;
116 p_bytestream->i_offset = 0;
117 p_bytestream->p_chain = p_bytestream->p_block = NULL;
121 while( p_block->p_next && p_block->p_next->p_next )
122 p_block = p_block->p_next;
125 block_t *p_block_old = p_block;
126 p_block = p_block->p_next;
127 p_block_old->p_next = NULL;
133 static inline int block_SkipByte( block_bytestream_t *p_bytestream )
135 /* Most common case first */
136 if( p_bytestream->p_block->i_buffer - p_bytestream->i_offset )
138 p_bytestream->i_offset++;
145 /* Less common case which is also slower */
146 for( p_block = p_bytestream->p_block->p_next;
147 p_block != NULL; p_block = p_block->p_next )
149 if( p_block->i_buffer )
151 p_bytestream->i_offset = 1;
152 p_bytestream->p_block = p_block;
158 /* Not enough data, bail out */
162 static inline int block_PeekByte( block_bytestream_t *p_bytestream,
165 /* Most common case first */
166 if( p_bytestream->p_block->i_buffer - p_bytestream->i_offset )
168 *p_data = p_bytestream->p_block->p_buffer[p_bytestream->i_offset];
175 /* Less common case which is also slower */
176 for( p_block = p_bytestream->p_block->p_next;
177 p_block != NULL; p_block = p_block->p_next )
179 if( p_block->i_buffer )
181 *p_data = p_block->p_buffer[0];
187 /* Not enough data, bail out */
191 static inline int block_GetByte( block_bytestream_t *p_bytestream,
194 /* Most common case first */
195 if( p_bytestream->p_block->i_buffer - p_bytestream->i_offset )
197 *p_data = p_bytestream->p_block->p_buffer[p_bytestream->i_offset];
198 p_bytestream->i_offset++;
205 /* Less common case which is also slower */
206 for( p_block = p_bytestream->p_block->p_next;
207 p_block != NULL; p_block = p_block->p_next )
209 if( p_block->i_buffer )
211 *p_data = p_block->p_buffer[0];
212 p_bytestream->i_offset = 1;
213 p_bytestream->p_block = p_block;
219 /* Not enough data, bail out */
223 static inline int block_WaitBytes( block_bytestream_t *p_bytestream,
227 size_t i_offset, i_copy, i_size;
229 /* Check we have that much data */
230 i_offset = p_bytestream->i_offset;
233 for( p_block = p_bytestream->p_block;
234 p_block != NULL; p_block = p_block->p_next )
236 i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
245 /* Not enough data, bail out */
251 static inline int block_SkipBytes( block_bytestream_t *p_bytestream,
255 size_t i_offset, i_copy;
257 /* Check we have that much data */
258 i_offset = p_bytestream->i_offset;
260 for( p_block = p_bytestream->p_block;
261 p_block != NULL; p_block = p_block->p_next )
263 i_copy = __MIN( i_data, p_block->i_buffer - i_offset );
273 /* Not enough data, bail out */
277 p_bytestream->p_block = p_block;
278 p_bytestream->i_offset = i_offset + i_copy;
282 static inline int block_PeekBytes( block_bytestream_t *p_bytestream,
283 uint8_t *p_data, size_t i_data )
286 size_t i_offset, i_copy, i_size;
288 /* Check we have that much data */
289 i_offset = p_bytestream->i_offset;
292 for( p_block = p_bytestream->p_block;
293 p_block != NULL; p_block = p_block->p_next )
295 i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
304 /* Not enough data, bail out */
309 i_offset = p_bytestream->i_offset;
312 for( p_block = p_bytestream->p_block;
313 p_block != NULL; p_block = p_block->p_next )
315 i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
320 memcpy( p_data, p_block->p_buffer + i_offset, i_copy );
332 static inline int block_GetBytes( block_bytestream_t *p_bytestream,
333 uint8_t *p_data, size_t i_data )
336 size_t i_offset, i_copy, i_size;
338 /* Check we have that much data */
339 i_offset = p_bytestream->i_offset;
342 for( p_block = p_bytestream->p_block;
343 p_block != NULL; p_block = p_block->p_next )
345 i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
354 /* Not enough data, bail out */
359 i_offset = p_bytestream->i_offset;
362 for( p_block = p_bytestream->p_block;
363 p_block != NULL; p_block = p_block->p_next )
365 i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
370 memcpy( p_data, p_block->p_buffer + i_offset, i_copy );
379 /* No buffer given, just skip the data */
380 p_bytestream->p_block = p_block;
381 p_bytestream->i_offset = i_offset + i_copy;
386 static inline int block_PeekOffsetBytes( block_bytestream_t *p_bytestream,
387 size_t i_peek_offset, uint8_t *p_data, size_t i_data )
390 size_t i_offset, i_copy, i_size;
392 /* Check we have that much data */
393 i_offset = p_bytestream->i_offset;
394 i_size = i_data + i_peek_offset;
396 for( p_block = p_bytestream->p_block;
397 p_block != NULL; p_block = p_block->p_next )
399 i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
408 /* Not enough data, bail out */
412 /* Find the right place */
413 i_offset = p_bytestream->i_offset;
414 i_size = i_peek_offset;
416 for( p_block = p_bytestream->p_block;
417 p_block != NULL; p_block = p_block->p_next )
419 i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
431 for( ; p_block != NULL; p_block = p_block->p_next )
433 i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
438 memcpy( p_data, p_block->p_buffer + i_offset, i_copy );
450 static inline int block_FindStartcodeFromOffset(
451 block_bytestream_t *p_bytestream, size_t *pi_offset,
452 const uint8_t *p_startcode, int i_startcode_length )
454 block_t *p_block, *p_block_backup = 0;
456 size_t i_offset, i_offset_backup = 0;
457 int i_caller_offset_backup = 0, i_match;
459 /* Find the right place */
460 i_size = *pi_offset + p_bytestream->i_offset;
461 for( p_block = p_bytestream->p_block;
462 p_block != NULL; p_block = p_block->p_next )
464 i_size -= p_block->i_buffer;
465 if( i_size < 0 ) break;
470 /* Not enough data, bail out */
475 * We first look for an occurrence of the 1st startcode byte and
476 * if found, we do a more thorough check. */
477 i_size += p_block->i_buffer;
478 *pi_offset -= i_size;
480 for( ; p_block != NULL; p_block = p_block->p_next )
482 for( i_offset = i_size; i_offset < p_block->i_buffer; i_offset++ )
484 if( p_block->p_buffer[i_offset] == p_startcode[i_match] )
488 p_block_backup = p_block;
489 i_offset_backup = i_offset;
490 i_caller_offset_backup = *pi_offset;
493 if( i_match + 1 == i_startcode_length )
496 *pi_offset += i_offset - i_match;
505 p_block = p_block_backup;
506 i_offset = i_offset_backup;
507 *pi_offset = i_caller_offset_backup;
513 *pi_offset += i_offset;
516 *pi_offset -= i_match;
520 #endif /* VLC_BLOCK_HELPER_H */