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 #if !defined( __LIBVLC__ )
25 #error You are not libvlc or one of its plugins. You cannot include this file
28 #ifndef _VLC_BLOCK_HELPER_H
29 #define _VLC_BLOCK_HELPER_H 1
31 #include <vlc_block.h>
33 typedef struct block_bytestream_t
41 /*****************************************************************************
42 * block_bytestream_t management
43 *****************************************************************************/
44 static inline block_bytestream_t block_BytestreamInit( void )
46 block_bytestream_t bytestream;
48 bytestream.i_offset = 0;
49 bytestream.p_chain = bytestream.p_block = NULL;
54 static inline void block_BytestreamRelease( block_bytestream_t *p_bytestream )
56 while( p_bytestream->p_chain )
59 p_next = p_bytestream->p_chain->p_next;
60 p_bytestream->p_chain->pf_release( p_bytestream->p_chain );
61 p_bytestream->p_chain = p_next;
63 p_bytestream->i_offset = 0;
64 p_bytestream->p_chain = p_bytestream->p_block = NULL;
67 static inline void block_BytestreamFlush( block_bytestream_t *p_bytestream )
69 while( p_bytestream->p_chain != p_bytestream->p_block )
72 p_next = p_bytestream->p_chain->p_next;
73 p_bytestream->p_chain->pf_release( p_bytestream->p_chain );
74 p_bytestream->p_chain = p_next;
76 while( p_bytestream->p_block &&
77 (p_bytestream->p_block->i_buffer - p_bytestream->i_offset) == 0 )
80 p_next = p_bytestream->p_chain->p_next;
81 p_bytestream->p_chain->pf_release( p_bytestream->p_chain );
82 p_bytestream->p_chain = p_bytestream->p_block = p_next;
83 p_bytestream->i_offset = 0;
87 static inline void block_BytestreamPush( block_bytestream_t *p_bytestream,
90 block_ChainAppend( &p_bytestream->p_chain, p_block );
91 if( !p_bytestream->p_block ) p_bytestream->p_block = p_block;
94 static inline block_t *block_BytestreamPop( block_bytestream_t *p_bytestream )
98 block_BytestreamFlush( p_bytestream );
100 p_block = p_bytestream->p_block;
101 if( p_block == NULL )
105 else if( !p_block->p_next )
107 p_block->p_buffer += p_bytestream->i_offset;
108 p_block->i_buffer -= p_bytestream->i_offset;
109 p_bytestream->i_offset = 0;
110 p_bytestream->p_chain = p_bytestream->p_block = NULL;
114 while( p_block->p_next && p_block->p_next->p_next )
115 p_block = p_block->p_next;
118 block_t *p_block_old = p_block;
119 p_block = p_block->p_next;
120 p_block_old->p_next = NULL;
126 static inline int block_SkipByte( block_bytestream_t *p_bytestream )
128 /* Most common case first */
129 if( p_bytestream->p_block->i_buffer - p_bytestream->i_offset )
131 p_bytestream->i_offset++;
138 /* Less common case which is also slower */
139 for( p_block = p_bytestream->p_block->p_next;
140 p_block != NULL; p_block = p_block->p_next )
142 if( p_block->i_buffer )
144 p_bytestream->i_offset = 1;
145 p_bytestream->p_block = p_block;
151 /* Not enough data, bail out */
155 static inline int block_PeekByte( block_bytestream_t *p_bytestream,
158 /* Most common case first */
159 if( p_bytestream->p_block->i_buffer - p_bytestream->i_offset )
161 *p_data = p_bytestream->p_block->p_buffer[p_bytestream->i_offset];
168 /* Less common case which is also slower */
169 for( p_block = p_bytestream->p_block->p_next;
170 p_block != NULL; p_block = p_block->p_next )
172 if( p_block->i_buffer )
174 *p_data = p_block->p_buffer[0];
180 /* Not enough data, bail out */
184 static inline int block_GetByte( block_bytestream_t *p_bytestream,
187 /* Most common case first */
188 if( p_bytestream->p_block->i_buffer - p_bytestream->i_offset )
190 *p_data = p_bytestream->p_block->p_buffer[p_bytestream->i_offset];
191 p_bytestream->i_offset++;
198 /* Less common case which is also slower */
199 for( p_block = p_bytestream->p_block->p_next;
200 p_block != NULL; p_block = p_block->p_next )
202 if( p_block->i_buffer )
204 *p_data = p_block->p_buffer[0];
205 p_bytestream->i_offset = 1;
206 p_bytestream->p_block = p_block;
212 /* Not enough data, bail out */
216 static inline int block_WaitBytes( block_bytestream_t *p_bytestream,
220 size_t i_offset, i_copy, i_size;
222 /* Check we have that much data */
223 i_offset = p_bytestream->i_offset;
226 for( p_block = p_bytestream->p_block;
227 p_block != NULL; p_block = p_block->p_next )
229 i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
238 /* Not enough data, bail out */
244 static inline int block_SkipBytes( block_bytestream_t *p_bytestream,
248 size_t i_offset, i_copy;
250 /* Check we have that much data */
251 i_offset = p_bytestream->i_offset;
253 for( p_block = p_bytestream->p_block;
254 p_block != NULL; p_block = p_block->p_next )
256 i_copy = __MIN( i_data, p_block->i_buffer - i_offset );
266 /* Not enough data, bail out */
270 p_bytestream->p_block = p_block;
271 p_bytestream->i_offset = i_offset + i_copy;
275 static inline int block_PeekBytes( block_bytestream_t *p_bytestream,
276 uint8_t *p_data, size_t i_data )
279 size_t i_offset, i_copy, i_size;
281 /* Check we have that much data */
282 i_offset = p_bytestream->i_offset;
285 for( p_block = p_bytestream->p_block;
286 p_block != NULL; p_block = p_block->p_next )
288 i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
297 /* Not enough data, bail out */
302 i_offset = p_bytestream->i_offset;
305 for( p_block = p_bytestream->p_block;
306 p_block != NULL; p_block = p_block->p_next )
308 i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
313 memcpy( p_data, p_block->p_buffer + i_offset, i_copy );
325 static inline int block_GetBytes( block_bytestream_t *p_bytestream,
326 uint8_t *p_data, size_t i_data )
329 size_t i_offset, i_copy, i_size;
331 /* Check we have that much data */
332 i_offset = p_bytestream->i_offset;
335 for( p_block = p_bytestream->p_block;
336 p_block != NULL; p_block = p_block->p_next )
338 i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
347 /* Not enough data, bail out */
352 i_offset = p_bytestream->i_offset;
355 for( p_block = p_bytestream->p_block;
356 p_block != NULL; p_block = p_block->p_next )
358 i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
363 memcpy( p_data, p_block->p_buffer + i_offset, i_copy );
372 /* No buffer given, just skip the data */
373 p_bytestream->p_block = p_block;
374 p_bytestream->i_offset = i_offset + i_copy;
379 static inline int block_PeekOffsetBytes( block_bytestream_t *p_bytestream,
380 size_t i_peek_offset, uint8_t *p_data, size_t i_data )
383 size_t i_offset, i_copy, i_size;
385 /* Check we have that much data */
386 i_offset = p_bytestream->i_offset;
387 i_size = i_data + i_peek_offset;
389 for( p_block = p_bytestream->p_block;
390 p_block != NULL; p_block = p_block->p_next )
392 i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
401 /* Not enough data, bail out */
405 /* Find the right place */
406 i_offset = p_bytestream->i_offset;
407 i_size = i_peek_offset;
409 for( p_block = p_bytestream->p_block;
410 p_block != NULL; p_block = p_block->p_next )
412 i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
424 for( ; p_block != NULL; p_block = p_block->p_next )
426 i_copy = __MIN( i_size, p_block->i_buffer - i_offset );
431 memcpy( p_data, p_block->p_buffer + i_offset, i_copy );
443 static inline int block_FindStartcodeFromOffset(
444 block_bytestream_t *p_bytestream, size_t *pi_offset,
445 uint8_t *p_startcode, int i_startcode_length )
447 block_t *p_block, *p_block_backup = 0;
449 size_t i_offset, i_offset_backup = 0;
450 int i_caller_offset_backup = 0, i_match;
452 /* Find the right place */
453 i_size = *pi_offset + p_bytestream->i_offset;
454 for( p_block = p_bytestream->p_block;
455 p_block != NULL; p_block = p_block->p_next )
457 i_size -= p_block->i_buffer;
458 if( i_size < 0 ) break;
463 /* Not enough data, bail out */
468 * We first look for an occurrence of the 1st startcode byte and
469 * if found, we do a more thorough check. */
470 i_size += p_block->i_buffer;
471 *pi_offset -= i_size;
473 for( ; p_block != NULL; p_block = p_block->p_next )
475 for( i_offset = i_size; i_offset < p_block->i_buffer; i_offset++ )
477 if( p_block->p_buffer[i_offset] == p_startcode[i_match] )
481 p_block_backup = p_block;
482 i_offset_backup = i_offset;
483 i_caller_offset_backup = *pi_offset;
486 if( i_match + 1 == i_startcode_length )
489 *pi_offset += i_offset - i_match;
498 p_block = p_block_backup;
499 i_offset = i_offset_backup;
500 *pi_offset = i_caller_offset_backup;
506 *pi_offset += i_offset;
509 *pi_offset -= i_match;
513 #endif /* VLC_BLOCK_HELPER_H */