git.sesse.net Git - vlc/blob - src/misc/block.c

   1 /*****************************************************************************
   2  * block.c: Data blocks management functions
   3  *****************************************************************************
   4  * Copyright (C) 2003-2004 VideoLAN
   5  * $Id$
   6  *
   7  * Authors: Laurent Aimar <fenrir@videolan.org>
   8  *
   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.
  13  *
  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.
  18  *
  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  *****************************************************************************/
  23
  24 /*****************************************************************************
  25  * Preamble
  26  *****************************************************************************/
  27 #include <stdlib.h>
  28
  29 #include <vlc/vlc.h>
  30 #include "vlc_block.h"
  31
  32 /*****************************************************************************
  33  * Block functions.
  34  *****************************************************************************/
  35 /* private */
  36 struct block_sys_t
  37 {
  38     uint8_t     *p_allocated_buffer;
  39     int         i_allocated_buffer;
  40 };
  41
  42 #define BLOCK_PADDING_SIZE 32
  43 static void BlockRelease( block_t * );
  44
  45 block_t *__block_New( vlc_object_t *p_obj, int i_size )
  46 {
  47     /* We do only one malloc
  48      * TODO bench if doing 2 malloc but keeping a pool of buffer is better
  49      * 16 -> align on 16
  50      * 2 * BLOCK_PADDING_SIZE -> pre + post padding
  51      */
  52     block_sys_t *p_sys;
  53     const int i_alloc = i_size + 2 * BLOCK_PADDING_SIZE + 16;
  54     block_t *p_block =
  55         malloc( sizeof( block_t ) + sizeof( block_sys_t ) + i_alloc );
  56
  57     if( p_block == NULL ) return NULL;
  58
  59     /* Fill opaque data */
  60     p_sys = (block_sys_t*)( (uint8_t*)p_block + sizeof( block_t ) );
  61     p_sys->i_allocated_buffer = i_alloc;
  62     p_sys->p_allocated_buffer = (uint8_t*)p_block + sizeof( block_t ) +
  63         sizeof( block_sys_t );
  64
  65     /* Fill all fields */
  66     p_block->p_next         = NULL;
  67     p_block->i_flags        = 0;
  68     p_block->i_pts          = 0;
  69     p_block->i_dts          = 0;
  70     p_block->i_length       = 0;
  71     p_block->i_rate         = 0;
  72     p_block->i_buffer       = i_size;
  73     p_block->p_buffer       =
  74         &p_sys->p_allocated_buffer[BLOCK_PADDING_SIZE +
  75             16 - ((uintptr_t)p_sys->p_allocated_buffer % 16 )];
  76     p_block->pf_release     = BlockRelease;
  77
  78     /* Is ok, as no comunication between p_vlc */
  79     p_block->p_manager      = VLC_OBJECT( p_obj->p_vlc );
  80     p_block->p_sys          = p_sys;
  81
  82     return p_block;
  83 }
  84
  85 block_t *block_Realloc( block_t *p_block, int i_prebody, int i_body )
  86 {
  87     int i_buffer_size;
  88
  89     if( p_block->pf_release != BlockRelease )
  90     {
  91         /* Special case when pf_release if overloaded
  92          * TODO if used one day, them implement it in a smarter way */
  93         block_t *p_dup = block_Duplicate( p_block );
  94         block_Release( p_block );
  95
  96         p_block = p_dup;
  97     }
  98
  99     i_buffer_size = i_prebody + i_body;
 100
 101     if( i_body < 0 || i_buffer_size <= 0 ) return NULL;
 102
 103     if( i_prebody < ( p_block->p_buffer - p_block->p_sys->p_allocated_buffer +
 104                       p_block->p_sys->i_allocated_buffer ) ||
 105         p_block->p_buffer - i_prebody > p_block->p_sys->p_allocated_buffer )
 106     {
 107         p_block->p_buffer -= i_prebody;
 108         p_block->i_buffer += i_prebody;
 109         i_prebody = 0;
 110     }
 111     if( p_block->p_buffer + i_body < p_block->p_sys->p_allocated_buffer +
 112         p_block->p_sys->i_allocated_buffer )
 113     {
 114         p_block->i_buffer = i_buffer_size;
 115         i_body = 0;
 116     }
 117
 118     if( i_body > 0 || i_prebody > 0 )
 119     {
 120         block_t *p_rea = block_New( p_block->p_manager, i_buffer_size );
 121
 122         p_rea->i_dts     = p_block->i_dts;
 123         p_rea->i_pts     = p_block->i_pts;
 124         p_rea->i_flags   = p_block->i_flags;
 125         p_rea->i_length  = p_block->i_length;
 126         p_rea->i_rate    = p_block->i_rate;
 127         p_rea->i_samples = p_block->i_samples;
 128
 129         memcpy( p_rea->p_buffer + i_prebody, p_block->p_buffer,
 130                 __MIN( p_block->i_buffer, p_rea->i_buffer - i_prebody ) );
 131
 132         block_Release( p_block );
 133
 134         return p_rea;
 135     }
 136
 137     return p_block;
 138 }
 139
 140 static void BlockRelease( block_t *p_block )
 141 {
 142     free( p_block );
 143 }
 144
 145
 146 /*****************************************************************************
 147  * block_fifo_t management
 148  *****************************************************************************/
 149 block_fifo_t *__block_FifoNew( vlc_object_t *p_obj )
 150 {
 151     block_fifo_t *p_fifo;
 152
 153     p_fifo = malloc( sizeof( vlc_object_t ) );
 154     vlc_mutex_init( p_obj, &p_fifo->lock );
 155     vlc_cond_init( p_obj, &p_fifo->wait );
 156     p_fifo->i_depth = p_fifo->i_size = 0;
 157     p_fifo->p_first = NULL;
 158     p_fifo->pp_last = &p_fifo->p_first;
 159
 160     return p_fifo;
 161 }
 162
 163 void block_FifoRelease( block_fifo_t *p_fifo )
 164 {
 165     block_FifoEmpty( p_fifo );
 166     vlc_cond_destroy( &p_fifo->wait );
 167     vlc_mutex_destroy( &p_fifo->lock );
 168     free( p_fifo );
 169 }
 170
 171 void block_FifoEmpty( block_fifo_t *p_fifo )
 172 {
 173     block_t *b;
 174
 175     vlc_mutex_lock( &p_fifo->lock );
 176     for( b = p_fifo->p_first; b != NULL; )
 177     {
 178         block_t *p_next;
 179
 180         p_next = b->p_next;
 181         block_Release( b );
 182         b = p_next;
 183     }
 184
 185     p_fifo->i_depth = p_fifo->i_size = 0;
 186     p_fifo->p_first = NULL;
 187     p_fifo->pp_last = &p_fifo->p_first;
 188     vlc_mutex_unlock( &p_fifo->lock );
 189 }
 190
 191 int block_FifoPut( block_fifo_t *p_fifo, block_t *p_block )
 192 {
 193     int i_size = 0;
 194     vlc_mutex_lock( &p_fifo->lock );
 195
 196     do
 197     {
 198         i_size += p_block->i_buffer;
 199
 200         *p_fifo->pp_last = p_block;
 201         p_fifo->pp_last = &p_block->p_next;
 202         p_fifo->i_depth++;
 203         p_fifo->i_size += p_block->i_buffer;
 204
 205         p_block = p_block->p_next;
 206
 207     } while( p_block );
 208
 209     /* warn there is data in this fifo */
 210     vlc_cond_signal( &p_fifo->wait );
 211     vlc_mutex_unlock( &p_fifo->lock );
 212
 213     return i_size;
 214 }
 215
 216 block_t *block_FifoGet( block_fifo_t *p_fifo )
 217 {
 218     block_t *b;
 219
 220     vlc_mutex_lock( &p_fifo->lock );
 221
 222     /* We do a while here because there is a race condition in the
 223      * win32 implementation of vlc_cond_wait() (We can't be sure the fifo
 224      * hasn't been emptied again since we were signaled). */
 225     while( p_fifo->p_first == NULL )
 226     {
 227         vlc_cond_wait( &p_fifo->wait, &p_fifo->lock );
 228     }
 229
 230     b = p_fifo->p_first;
 231
 232     p_fifo->p_first = b->p_next;
 233     p_fifo->i_depth--;
 234     p_fifo->i_size -= b->i_buffer;
 235
 236     if( p_fifo->p_first == NULL )
 237     {
 238         p_fifo->pp_last = &p_fifo->p_first;
 239     }
 240
 241     vlc_mutex_unlock( &p_fifo->lock );
 242
 243     b->p_next = NULL;
 244     return b;
 245 }
 246
 247 block_t *block_FifoShow( block_fifo_t *p_fifo )
 248 {
 249     block_t *b;
 250
 251     vlc_mutex_lock( &p_fifo->lock );
 252
 253     if( p_fifo->p_first == NULL )
 254     {
 255         vlc_cond_wait( &p_fifo->wait, &p_fifo->lock );
 256     }
 257
 258     b = p_fifo->p_first;
 259
 260     vlc_mutex_unlock( &p_fifo->lock );
 261
 262     return( b );
 263
 264 }
 265