1 /*****************************************************************************
2 * vlc_block.h: Data blocks management functions
3 *****************************************************************************
4 * Copyright (C) 2003 the VideoLAN team
7 * Authors: Laurent Aimar <fenrir@via.ecp.fr>
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 *****************************************************************************/
29 * This file implements functions and structures to handle blocks of data in vlc
33 /****************************************************************************
35 ****************************************************************************
36 * - block_sys_t is opaque and thus block_t->p_sys is PRIVATE
37 * - i_flags may not always be set (ie could be 0, even for a key frame
38 * it depends where you receive the buffer (before/after a packetizer
39 * and the demux/packetizer implementations.
40 * - i_dts/i_pts could be 0, it means no pts
41 * - i_length: length in microseond of the packet, can be null except in the
42 * sout where it is mandatory.
43 * - i_rate 0 or a valid input rate, look at vlc_input.h
45 * - i_buffer number of valid data pointed by p_buffer
46 * you can freely decrease it but never increase it yourself
48 * - p_buffer: pointer over datas. You should never overwrite it, you can
49 * only incremment it to skip datas, in others cases use block_Realloc
50 * (don't duplicate yourself in a bigger buffer, block_Realloc is
51 * optimised for prehader/postdatas increase)
52 ****************************************************************************/
53 typedef struct block_sys_t block_sys_t;
55 /** The content doesn't follow the last block, or is probably broken */
56 #define BLOCK_FLAG_DISCONTINUITY 0x0001
58 #define BLOCK_FLAG_TYPE_I 0x0002
59 /** Inter frame with backward reference only */
60 #define BLOCK_FLAG_TYPE_P 0x0004
61 /** Inter frame with backward and forward reference */
62 #define BLOCK_FLAG_TYPE_B 0x0008
63 /** For inter frame when you don't know the real type */
64 #define BLOCK_FLAG_TYPE_PB 0x0010
65 /** Warn that this block is a header one */
66 #define BLOCK_FLAG_HEADER 0x0020
67 /** This is the last block of the frame */
68 #define BLOCK_FLAG_END_OF_FRAME 0x0040
69 /** This is not a key frame for bitrate shaping */
70 #define BLOCK_FLAG_NO_KEYFRAME 0x0080
71 /** This block contains a clock reference */
72 #define BLOCK_FLAG_CLOCK 0x0200
73 /** This block is scrambled */
74 #define BLOCK_FLAG_SCRAMBLED 0x0400
75 /** This block has to be decoded but not be displayed */
76 #define BLOCK_FLAG_PREROLL 0x0800
77 /** This block is corrupted and/or there is data loss */
78 #define BLOCK_FLAG_CORRUPTED 0x1000
80 #define BLOCK_FLAG_PRIVATE_MASK 0xffff0000
81 #define BLOCK_FLAG_PRIVATE_SHIFT 16
83 typedef void (*block_free_t) (block_t *);
96 int i_samples; /* Used for audio */
102 /* Rudimentary support for overloading block (de)allocation. */
103 block_free_t pf_release;
106 /****************************************************************************
108 ****************************************************************************
109 * - block_Alloc : create a new block with the requested size ( >= 0 ), return
111 * - block_Release : release a block allocated with block_Alloc.
112 * - block_Realloc : realloc a block,
113 * i_pre: how many bytes to insert before body if > 0, else how many
114 * bytes of body to skip (the latter can be done without using
115 * block_Realloc i_buffer -= -i_pre, p_buffer += -i_pre as i_pre < 0)
116 * i_body (>= 0): the final size of the body (decreasing it can directly
117 * be done with i_buffer = i_body).
118 * with preheader and or body (increase
119 * and decrease are supported). Use it as it is optimised.
120 * - block_Duplicate : create a copy of a block.
121 ****************************************************************************/
122 VLC_EXPORT( void, block_Init, ( block_t *, void *, size_t ) );
123 VLC_EXPORT( block_t *, block_Alloc, ( size_t ) );
124 VLC_EXPORT( block_t *, block_Realloc, ( block_t *, ssize_t i_pre, size_t i_body ) );
126 #define block_New( dummy, size ) block_Alloc(size)
128 static inline block_t *block_Duplicate( block_t *p_block )
130 block_t *p_dup = block_Alloc( p_block->i_buffer );
134 p_dup->i_dts = p_block->i_dts;
135 p_dup->i_pts = p_block->i_pts;
136 p_dup->i_flags = p_block->i_flags;
137 p_dup->i_length = p_block->i_length;
138 p_dup->i_rate = p_block->i_rate;
139 p_dup->i_samples = p_block->i_samples;
140 memcpy( p_dup->p_buffer, p_block->p_buffer, p_block->i_buffer );
145 static inline void block_Release( block_t *p_block )
147 p_block->pf_release( p_block );
150 VLC_EXPORT( block_t *, block_mmap_Alloc, (void *addr, size_t length) );
151 VLC_EXPORT( block_t *, block_File, (int fd) );
153 /****************************************************************************
154 * Chains of blocks functions helper
155 ****************************************************************************
156 * - block_ChainAppend : append a block to the last block of a chain. Try to
157 * avoid using with a lot of data as it's really slow, prefer
158 * block_ChainLastAppend
159 * - block_ChainLastAppend : use a pointer over a pointer to the next blocks,
161 * - block_ChainRelease : release a chain of block
162 * - block_ChainExtract : extract data from a chain, return real bytes counts
163 * - block_ChainGather : gather a chain, free it and return one block.
164 ****************************************************************************/
165 static inline void block_ChainAppend( block_t **pp_list, block_t *p_block )
167 if( *pp_list == NULL )
173 block_t *p = *pp_list;
175 while( p->p_next ) p = p->p_next;
180 static inline void block_ChainLastAppend( block_t ***ppp_last, block_t *p_block )
182 block_t *p_last = p_block;
184 **ppp_last = p_block;
186 while( p_last->p_next ) p_last = p_last->p_next;
187 *ppp_last = &p_last->p_next;
190 static inline void block_ChainRelease( block_t *p_block )
194 block_t *p_next = p_block->p_next;
195 block_Release( p_block );
200 static size_t block_ChainExtract( block_t *p_list, void *p_data, size_t i_max )
203 uint8_t *p = (uint8_t*)p_data;
205 while( p_list && i_max )
207 size_t i_copy = __MIN( i_max, p_list->i_buffer );
208 memcpy( p, p_list->p_buffer, i_copy );
213 p_list = p_list->p_next;
218 static inline block_t *block_ChainGather( block_t *p_list )
221 mtime_t i_length = 0;
224 if( p_list->p_next == NULL )
225 return p_list; /* Already gathered */
227 for( b = p_list; b != NULL; b = b->p_next )
229 i_total += b->i_buffer;
230 i_length += b->i_length;
233 g = block_Alloc( i_total );
234 block_ChainExtract( p_list, g->p_buffer, g->i_buffer );
236 g->i_flags = p_list->i_flags;
237 g->i_pts = p_list->i_pts;
238 g->i_dts = p_list->i_dts;
239 g->i_length = i_length;
242 block_ChainRelease( p_list );
246 /****************************************************************************
248 ****************************************************************************
249 * - block_FifoNew : create and init a new fifo
250 * - block_FifoRelease : destroy a fifo and free all blocks in it.
251 * - block_FifoEmpty : free all blocks in a fifo
252 * - block_FifoPut : put a block
253 * - block_FifoGet : get a packet from the fifo (and wait if it is empty)
254 * - block_FifoShow : show the first packet of the fifo (and wait if
255 * needed), be carefull, you can use it ONLY if you are sure to be the
256 * only one getting data from the fifo.
257 * - block_FifoCount : how many packets are waiting in the fifo
258 * - block_FifoSize : how many cumulated bytes are waiting in the fifo
259 * - block_FifoWake : wake ups a thread with block_FifoGet() = NULL
260 * (this is used to wakeup a thread when there is no data to queue)
261 ****************************************************************************/
263 VLC_EXPORT( block_fifo_t *, block_FifoNew, ( void ) );
264 VLC_EXPORT( void, block_FifoRelease, ( block_fifo_t * ) );
265 VLC_EXPORT( void, block_FifoEmpty, ( block_fifo_t * ) );
266 VLC_EXPORT( size_t, block_FifoPut, ( block_fifo_t *, block_t * ) );
267 VLC_EXPORT( void, block_FifoWake, ( block_fifo_t * ) );
268 VLC_EXPORT( block_t *, block_FifoGet, ( block_fifo_t * ) );
269 VLC_EXPORT( block_t *, block_FifoShow, ( block_fifo_t * ) );
270 VLC_EXPORT( size_t, block_FifoSize, ( const block_fifo_t *p_fifo ) );
271 VLC_EXPORT( size_t, block_FifoCount, ( const block_fifo_t *p_fifo ) );
273 #endif /* VLC_BLOCK_H */