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

   1 /*****************************************************************************
   2  * block.c: Data blocks management functions
   3  *****************************************************************************
   4  * Copyright (C) 2003-2004 the VideoLAN team
   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., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  22  *****************************************************************************/
  23
  24 /*****************************************************************************
  25  * Preamble
  26  *****************************************************************************/
  27 #include <vlc/vlc.h>
  28 #include "vlc_block.h"
  29
  30 /*****************************************************************************
  31  * Block functions.
  32  *****************************************************************************/
  33 /* private */
  34 struct block_sys_t
  35 {
  36     uint8_t     *p_allocated_buffer;
  37     int         i_allocated_buffer;
  38 };
  39
  40 #define BLOCK_PADDING_SIZE 32
  41 static void BlockRelease( block_t * );
  42
  43 block_t *__block_New( vlc_object_t *p_obj, int i_size )
  44 {
  45     /* We do only one malloc
  46      * TODO bench if doing 2 malloc but keeping a pool of buffer is better
  47      * 16 -> align on 16
  48      * 2 * BLOCK_PADDING_SIZE -> pre + post padding
  49      */
  50     block_sys_t *p_sys;
  51     const int i_alloc = i_size + 2 * BLOCK_PADDING_SIZE + 16;
  52     block_t *p_block =
  53         malloc( sizeof( block_t ) + sizeof( block_sys_t ) + i_alloc );
  54
  55     if( p_block == NULL )
  56         return NULL;
  57
  58     /* Fill opaque data */
  59     p_sys = (block_sys_t*)( (uint8_t*)p_block + sizeof( block_t ) );
  60     p_sys->i_allocated_buffer = i_alloc;
  61     p_sys->p_allocated_buffer = (uint8_t*)p_block + sizeof( block_t ) +
  62         sizeof( block_sys_t );
  63
  64     /* Fill all fields */
  65     p_block->p_next         = NULL;
  66     p_block->p_prev         = 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_libvlc );
  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         if( !p_dup )
  96             return NULL;
  97
  98         p_block = p_dup;
  99     }
 100
 101     i_buffer_size = i_prebody + i_body;
 102
 103     if( i_body < 0 || i_buffer_size <= 0 )
 104     {
 105         block_Release( p_block );
 106         return NULL;
 107     }
 108
 109     if( p_block->p_buffer - i_prebody > p_block->p_sys->p_allocated_buffer &&
 110         p_block->p_buffer - i_prebody < p_block->p_sys->p_allocated_buffer +
 111         p_block->p_sys->i_allocated_buffer )
 112     {
 113         p_block->p_buffer -= i_prebody;
 114         p_block->i_buffer += i_prebody;
 115         i_prebody = 0;
 116     }
 117     if( p_block->p_buffer + i_body < p_block->p_sys->p_allocated_buffer +
 118         p_block->p_sys->i_allocated_buffer )
 119     {
 120         p_block->i_buffer = i_buffer_size;
 121         i_body = 0;
 122     }
 123
 124     if( i_body > 0 || i_prebody > 0 )
 125     {
 126         block_t *p_rea = block_New( p_block->p_manager, i_buffer_size );
 127
 128         if( p_rea )
 129         {
 130             p_rea->i_dts     = p_block->i_dts;
 131             p_rea->i_pts     = p_block->i_pts;
 132             p_rea->i_flags   = p_block->i_flags;
 133             p_rea->i_length  = p_block->i_length;
 134             p_rea->i_rate    = p_block->i_rate;
 135             p_rea->i_samples = p_block->i_samples;
 136
 137             memcpy( p_rea->p_buffer + i_prebody, p_block->p_buffer,
 138                     __MIN( p_block->i_buffer, p_rea->i_buffer - i_prebody ) );
 139         }
 140
 141         block_Release( p_block );
 142
 143         return p_rea;
 144     }
 145
 146     return p_block;
 147 }
 148
 149 static void BlockRelease( block_t *p_block )
 150 {
 151     free( p_block );
 152 }
 153
 154
 155 /*****************************************************************************
 156  * block_fifo_t management
 157  *****************************************************************************/
 158 struct block_fifo_t
 159 {
 160     vlc_mutex_t         lock;                         /* fifo data lock */
 161     vlc_cond_t          wait;         /* fifo data conditional variable */
 162
 163     block_t             *p_first;
 164     block_t             **pp_last;
 165     size_t              i_depth;
 166     size_t              i_size;
 167     vlc_bool_t          b_force_wake;
 168 };
 169
 170 block_fifo_t *__block_FifoNew( vlc_object_t *p_obj )
 171 {
 172     block_fifo_t *p_fifo;
 173
 174     p_fifo = malloc( sizeof( block_fifo_t ) );
 175     if( !p_fifo ) return NULL;
 176     vlc_mutex_init( p_obj, &p_fifo->lock );
 177     vlc_cond_init( p_obj, &p_fifo->wait );
 178     p_fifo->p_first = NULL;
 179     p_fifo->pp_last = &p_fifo->p_first;
 180     p_fifo->i_depth = p_fifo->i_size = 0;
 181     p_fifo->b_force_wake = VLC_FALSE;
 182
 183     return p_fifo;
 184 }
 185
 186 void block_FifoRelease( block_fifo_t *p_fifo )
 187 {
 188     block_FifoEmpty( p_fifo );
 189     vlc_cond_destroy( &p_fifo->wait );
 190     vlc_mutex_destroy( &p_fifo->lock );
 191     free( p_fifo );
 192 }
 193
 194 void block_FifoEmpty( block_fifo_t *p_fifo )
 195 {
 196     block_t *b;
 197
 198     vlc_mutex_lock( &p_fifo->lock );
 199     for( b = p_fifo->p_first; b != NULL; )
 200     {
 201         block_t *p_next;
 202
 203         p_next = b->p_next;
 204         block_Release( b );
 205         b = p_next;
 206     }
 207
 208     p_fifo->i_depth = p_fifo->i_size = 0;
 209     p_fifo->p_first = NULL;
 210     p_fifo->pp_last = &p_fifo->p_first;
 211     vlc_mutex_unlock( &p_fifo->lock );
 212 }
 213
 214 int block_FifoPut( block_fifo_t *p_fifo, block_t *p_block )
 215 {
 216     int i_size = 0;
 217     vlc_mutex_lock( &p_fifo->lock );
 218
 219     do
 220     {
 221         i_size += p_block->i_buffer;
 222
 223         *p_fifo->pp_last = p_block;
 224         p_fifo->pp_last = &p_block->p_next;
 225         p_fifo->i_depth++;
 226         p_fifo->i_size += p_block->i_buffer;
 227
 228         p_block = p_block->p_next;
 229
 230     } while( p_block );
 231
 232     /* warn there is data in this fifo */
 233     vlc_cond_signal( &p_fifo->wait );
 234     vlc_mutex_unlock( &p_fifo->lock );
 235
 236     return i_size;
 237 }
 238
 239 void block_FifoWake( block_fifo_t *p_fifo )
 240 {
 241     vlc_mutex_lock( &p_fifo->lock );
 242     if( p_fifo->p_first == NULL )
 243         p_fifo->b_force_wake = VLC_TRUE;
 244     vlc_cond_signal( &p_fifo->wait );
 245     vlc_mutex_unlock( &p_fifo->lock );
 246 }
 247
 248 block_t *block_FifoGet( block_fifo_t *p_fifo )
 249 {
 250     block_t *b;
 251
 252     vlc_mutex_lock( &p_fifo->lock );
 253
 254     /* Remember vlc_cond_wait() may cause spurious wakeups
 255      * (on both Win32 and POSIX) */
 256     while( ( p_fifo->p_first == NULL ) && !p_fifo->b_force_wake )
 257     {
 258         vlc_cond_wait( &p_fifo->wait, &p_fifo->lock );
 259     }
 260
 261     b = p_fifo->p_first;
 262
 263     p_fifo->b_force_wake = VLC_FALSE;
 264     if( b == NULL )
 265     {
 266         /* Forced wakeup */
 267         vlc_mutex_unlock( &p_fifo->lock );
 268         return NULL;
 269     }
 270
 271     p_fifo->p_first = b->p_next;
 272     p_fifo->i_depth--;
 273     p_fifo->i_size -= b->i_buffer;
 274
 275     if( p_fifo->p_first == NULL )
 276     {
 277         p_fifo->pp_last = &p_fifo->p_first;
 278     }
 279
 280     vlc_mutex_unlock( &p_fifo->lock );
 281
 282     b->p_next = NULL;
 283     return b;
 284 }
 285
 286 block_t *block_FifoShow( block_fifo_t *p_fifo )
 287 {
 288     block_t *b;
 289
 290     vlc_mutex_lock( &p_fifo->lock );
 291
 292     if( p_fifo->p_first == NULL )
 293     {
 294         vlc_cond_wait( &p_fifo->wait, &p_fifo->lock );
 295     }
 296
 297     b = p_fifo->p_first;
 298
 299     vlc_mutex_unlock( &p_fifo->lock );
 300
 301     return( b );
 302 }
 303
 304 size_t block_FifoSize( const block_fifo_t *p_fifo )
 305 {
 306     return p_fifo->i_size;
 307 }
 308
 309 size_t block_FifoCount( const block_fifo_t *p_fifo )
 310 {
 311     return p_fifo->i_depth;
 312 }