1 /*****************************************************************************
2 * vlc_block_helper.h: Helper functions for data blocks management.
3 *****************************************************************************
4 * Copyright (C) 2003 VideoLAN
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., 59 Temple Place - Suite 330, Boston, MA 02111, USA.
22 *****************************************************************************/
24 #ifndef _VLC_BLOCK_HELPER_H
25 #define _VLC_BLOCK_HELPER_H 1
27 typedef struct block_bytestream_t
35 #define block_BytestreamInit( a ) __block_BytestreamInit( VLC_OBJECT(a) )
37 /*****************************************************************************
38 * block_bytestream_t management
39 *****************************************************************************/
40 static inline block_bytestream_t __block_BytestreamInit( vlc_object_t *p_obj )
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;
90 static inline block_t *block_BytestreamPop( block_bytestream_t *p_bytestream )
94 block_BytestreamFlush( p_bytestream );
96 p_block = p_bytestream->p_block;
101 else if( !p_block->p_next )
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;
110 while( p_block->p_next && p_block->p_next->p_next )
111 p_block = p_block->p_next;
114 block_t *p_block_old = p_block;
115 p_block = p_block->p_next;
116 p_block_old->p_next = NULL;
122 static inline int block_SkipByte( block_bytestream_t *p_bytestream )
124 /* Most common case first */
125 if( p_bytestream->p_block->i_buffer - p_bytestream->i_offset )
127 p_bytestream->i_offset++;
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 )
138 if( p_block->i_buffer )
140 p_bytestream->i_offset = 1;
141 p_bytestream->p_block = p_block;
147 /* Not enough data, bail out */
151 static inline int block_PeekByte( block_bytestream_t *p_bytestream,
154 /* Most common case first */
155 if( p_bytestream->p_block->i_buffer - p_bytestream->i_offset )
157 *p_data = p_bytestream->p_block->p_buffer[p_bytestream->i_offset];
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 )
168 if( p_block->i_buffer )
170 *p_data = p_block->p_buffer[0];
176 /* Not enough data, bail out */
180 static inline int block_GetByte( block_bytestream_t *p_bytestream,
183 /* Most common case first */
184 if( p_bytestream->p_block->i_buffer - p_bytestream->i_offset )
186 *p_data = p_bytestream->p_block->p_buffer[p_bytestream->i_offset];
187 p_bytestream->i_offset++;
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 )
198 if( p_block->i_buffer )
200 *p_data = p_block->p_buffer[0];
201 p_bytestream->i_offset = 1;
202 p_bytestream->p_block = p_block;
208 /* Not enough data, bail out */
212 static inline int block_WaitBytes( block_bytestream_t *p_bytestream,
216 int i_offset, i_copy, i_size;
218 /* Check we have that much data */
219 i_offset = p_bytestream->i_offset;
222 for( p_block = p_bytestream->p_block;
223 p_block != NULL; p_block = p_block->p_next )
225 i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
234 /* Not enough data, bail out */
240 static inline int block_SkipBytes( block_bytestream_t *p_bytestream,
244 int i_offset, i_copy;
246 /* Check we have that much data */
247 i_offset = p_bytestream->i_offset;
249 for( p_block = p_bytestream->p_block;
250 p_block != NULL; p_block = p_block->p_next )
252 i_copy = __MIN( i_data, p_block->i_buffer - i_offset );
262 /* Not enough data, bail out */
266 p_bytestream->p_block = p_block;
267 p_bytestream->i_offset = i_offset + i_copy;
271 static inline int block_PeekBytes( block_bytestream_t *p_bytestream,
272 uint8_t *p_data, int i_data )
275 int i_offset, i_copy, i_size;
277 /* Check we have that much data */
278 i_offset = p_bytestream->i_offset;
281 for( p_block = p_bytestream->p_block;
282 p_block != NULL; p_block = p_block->p_next )
284 i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
293 /* Not enough data, bail out */
298 i_offset = p_bytestream->i_offset;
301 for( p_block = p_bytestream->p_block;
302 p_block != NULL; p_block = p_block->p_next )
304 i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
309 memcpy( p_data, p_block->p_buffer + i_offset, i_copy );
321 static inline int block_GetBytes( block_bytestream_t *p_bytestream,
322 uint8_t *p_data, int i_data )
325 int i_offset, i_copy, i_size;
327 /* Check we have that much data */
328 i_offset = p_bytestream->i_offset;
331 for( p_block = p_bytestream->p_block;
332 p_block != NULL; p_block = p_block->p_next )
334 i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
343 /* Not enough data, bail out */
348 i_offset = p_bytestream->i_offset;
351 for( p_block = p_bytestream->p_block;
352 p_block != NULL; p_block = p_block->p_next )
354 i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
359 memcpy( p_data, p_block->p_buffer + i_offset, i_copy );
368 /* No buffer given, just skip the data */
369 p_bytestream->p_block = p_block;
370 p_bytestream->i_offset = i_offset + i_copy;
375 static inline int block_PeekOffsetBytes( block_bytestream_t *p_bytestream,
376 int i_peek_offset, uint8_t *p_data, int i_data )
379 int i_offset, i_copy, i_size;
381 /* Check we have that much data */
382 i_offset = p_bytestream->i_offset;
383 i_size = i_data + i_peek_offset;
385 for( p_block = p_bytestream->p_block;
386 p_block != NULL; p_block = p_block->p_next )
388 i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
397 /* Not enough data, bail out */
401 /* Find the right place */
402 i_offset = p_bytestream->i_offset;
403 i_size = i_peek_offset;
405 for( p_block = p_bytestream->p_block;
406 p_block != NULL; p_block = p_block->p_next )
408 i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
420 for( ; p_block != NULL; p_block = p_block->p_next )
422 i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
427 memcpy( p_data, p_block->p_buffer + i_offset, i_copy );
439 static inline int block_FindStartcodeFromOffset(
440 block_bytestream_t *p_bytestream, int *pi_offset,
441 uint8_t *p_startcode, int i_startcode_length )
443 block_t *p_block, *p_block_backup = 0;
444 int i_size, i_offset, i_offset_backup = 0;
445 int i_caller_offset_backup = 0, i_match;
447 /* Find the right place */
448 i_size = *pi_offset + p_bytestream->i_offset;
449 for( p_block = p_bytestream->p_block;
450 p_block != NULL; p_block = p_block->p_next )
452 i_size -= p_block->i_buffer;
453 if( i_size < 0 ) break;
458 /* Not enough data, bail out */
463 * We first look for an occurrence of the 1st startcode byte and
464 * if found, we do a more thorough check. */
465 i_size = p_block->i_buffer + i_size;
466 *pi_offset -= i_size;
468 for( ; p_block != NULL; p_block = p_block->p_next )
470 for( i_offset = i_size; i_offset < p_block->i_buffer; i_offset++ )
472 if( p_block->p_buffer[i_offset] == p_startcode[i_match] )
476 p_block_backup = p_block;
477 i_offset_backup = i_offset;
478 i_caller_offset_backup = *pi_offset;
481 if( i_match + 1 == i_startcode_length )
484 *pi_offset += i_offset - i_match;
493 p_block = p_block_backup;
494 i_offset = i_offset_backup;
495 *pi_offset = i_caller_offset_backup;
501 *pi_offset += i_offset;
504 *pi_offset -= i_match;
508 #endif /* VLC_BLOCK_HELPER_H */