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     size_t      i_allocated_buffer;
  37     uint8_t     p_allocated_buffer[0];
  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, size_t 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 size_t 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
  62     /* Fill all fields */
  63     p_block->p_next         = NULL;
  64     p_block->p_prev         = NULL;
  65     p_block->i_flags        = 0;
  66     p_block->i_pts          = 0;
  67     p_block->i_dts          = 0;
  68     p_block->i_length       = 0;
  69     p_block->i_rate         = 0;
  70     p_block->i_buffer       = i_size;
  71     p_block->p_buffer       =
  72         &p_sys->p_allocated_buffer[BLOCK_PADDING_SIZE +
  73             16 - ((uintptr_t)p_sys->p_allocated_buffer % 16 )];
  74     p_block->pf_release     = BlockRelease;
  75
  76     /* Is ok, as no comunication between p_vlc */
  77     p_block->p_sys          = p_sys;
  78
  79     return p_block;
  80 }
  81
  82 block_t *block_Realloc( block_t *p_block, ssize_t i_prebody, size_t i_body )
  83 {
  84     ssize_t i_buffer_size;
  85
  86     if( p_block->pf_release != BlockRelease )
  87     {
  88         /* Special case when pf_release if overloaded
  89          * TODO if used one day, them implement it in a smarter way */
  90         block_t *p_dup = block_Duplicate( p_block );
  91         block_Release( p_block );
  92         if( !p_dup )
  93             return NULL;
  94
  95         p_block = p_dup;
  96     }
  97
  98     i_buffer_size = i_prebody + i_body;
  99
 100     if( i_buffer_size <= 0 )
 101     {
 102         block_Release( p_block );
 103         return NULL;
 104     }
 105
 106     if( p_block->p_buffer - i_prebody > p_block->p_sys->p_allocated_buffer &&
 107         p_block->p_buffer - i_prebody < p_block->p_sys->p_allocated_buffer +
 108         p_block->p_sys->i_allocated_buffer )
 109     {
 110         p_block->p_buffer -= i_prebody;
 111         p_block->i_buffer += i_prebody;
 112         i_prebody = 0;
 113     }
 114     if( p_block->p_buffer + i_body < p_block->p_sys->p_allocated_buffer +
 115         p_block->p_sys->i_allocated_buffer )
 116     {
 117         p_block->i_buffer = i_buffer_size;
 118         i_body = 0;
 119     }
 120
 121     if( i_body > 0 || i_prebody > 0 )
 122     {
 123         block_t *p_rea = block_New( NULL, i_buffer_size );
 124
 125         if( p_rea )
 126         {
 127             p_rea->i_dts     = p_block->i_dts;
 128             p_rea->i_pts     = p_block->i_pts;
 129             p_rea->i_flags   = p_block->i_flags;
 130             p_rea->i_length  = p_block->i_length;
 131             p_rea->i_rate    = p_block->i_rate;
 132             p_rea->i_samples = p_block->i_samples;
 133
 134             memcpy( p_rea->p_buffer + i_prebody, p_block->p_buffer,
 135                     __MIN( p_block->i_buffer, p_rea->i_buffer - i_prebody ) );
 136         }
 137
 138         block_Release( p_block );
 139
 140         return p_rea;
 141     }
 142
 143     return p_block;
 144 }
 145
 146 static void BlockRelease( block_t *p_block )
 147 {
 148     free( p_block );
 149 }
 150
 151
 152 /*****************************************************************************
 153  * block_fifo_t management
 154  *****************************************************************************/
 155 struct block_fifo_t
 156 {
 157     vlc_mutex_t         lock;                         /* fifo data lock */
 158     vlc_cond_t          wait;         /* fifo data conditional variable */
 159
 160     block_t             *p_first;
 161     block_t             **pp_last;
 162     size_t              i_depth;
 163     size_t              i_size;
 164     vlc_bool_t          b_force_wake;
 165 };
 166
 167 block_fifo_t *__block_FifoNew( vlc_object_t *p_obj )
 168 {
 169     block_fifo_t *p_fifo;
 170
 171     p_fifo = malloc( sizeof( block_fifo_t ) );
 172     if( !p_fifo ) return NULL;
 173     vlc_mutex_init( p_obj, &p_fifo->lock );
 174     vlc_cond_init( p_obj, &p_fifo->wait );
 175     p_fifo->p_first = NULL;
 176     p_fifo->pp_last = &p_fifo->p_first;
 177     p_fifo->i_depth = p_fifo->i_size = 0;
 178     p_fifo->b_force_wake = VLC_FALSE;
 179
 180     return p_fifo;
 181 }
 182
 183 void block_FifoRelease( block_fifo_t *p_fifo )
 184 {
 185     block_FifoEmpty( p_fifo );
 186     vlc_cond_destroy( &p_fifo->wait );
 187     vlc_mutex_destroy( &p_fifo->lock );
 188     free( p_fifo );
 189 }
 190
 191 void block_FifoEmpty( block_fifo_t *p_fifo )
 192 {
 193     block_t *b;
 194
 195     vlc_mutex_lock( &p_fifo->lock );
 196     for( b = p_fifo->p_first; b != NULL; )
 197     {
 198         block_t *p_next;
 199
 200         p_next = b->p_next;
 201         block_Release( b );
 202         b = p_next;
 203     }
 204
 205     p_fifo->i_depth = p_fifo->i_size = 0;
 206     p_fifo->p_first = NULL;
 207     p_fifo->pp_last = &p_fifo->p_first;
 208     vlc_mutex_unlock( &p_fifo->lock );
 209 }
 210
 211 size_t block_FifoPut( block_fifo_t *p_fifo, block_t *p_block )
 212 {
 213     size_t i_size = 0;
 214     vlc_mutex_lock( &p_fifo->lock );
 215
 216     do
 217     {
 218         i_size += p_block->i_buffer;
 219
 220         *p_fifo->pp_last = p_block;
 221         p_fifo->pp_last = &p_block->p_next;
 222         p_fifo->i_depth++;
 223         p_fifo->i_size += p_block->i_buffer;
 224
 225         p_block = p_block->p_next;
 226
 227     } while( p_block );
 228
 229     /* warn there is data in this fifo */
 230     vlc_cond_signal( &p_fifo->wait );
 231     vlc_mutex_unlock( &p_fifo->lock );
 232
 233     return i_size;
 234 }
 235
 236 void block_FifoWake( block_fifo_t *p_fifo )
 237 {
 238     vlc_mutex_lock( &p_fifo->lock );
 239     if( p_fifo->p_first == NULL )
 240         p_fifo->b_force_wake = VLC_TRUE;
 241     vlc_cond_signal( &p_fifo->wait );
 242     vlc_mutex_unlock( &p_fifo->lock );
 243 }
 244
 245 block_t *block_FifoGet( block_fifo_t *p_fifo )
 246 {
 247     block_t *b;
 248
 249     vlc_mutex_lock( &p_fifo->lock );
 250
 251     /* Remember vlc_cond_wait() may cause spurious wakeups
 252      * (on both Win32 and POSIX) */
 253     while( ( p_fifo->p_first == NULL ) && !p_fifo->b_force_wake )
 254     {
 255         vlc_cond_wait( &p_fifo->wait, &p_fifo->lock );
 256     }
 257
 258     b = p_fifo->p_first;
 259
 260     p_fifo->b_force_wake = VLC_FALSE;
 261     if( b == NULL )
 262     {
 263         /* Forced wakeup */
 264         vlc_mutex_unlock( &p_fifo->lock );
 265         return NULL;
 266     }
 267
 268     p_fifo->p_first = b->p_next;
 269     p_fifo->i_depth--;
 270     p_fifo->i_size -= b->i_buffer;
 271
 272     if( p_fifo->p_first == NULL )
 273     {
 274         p_fifo->pp_last = &p_fifo->p_first;
 275     }
 276
 277     vlc_mutex_unlock( &p_fifo->lock );
 278
 279     b->p_next = NULL;
 280     return b;
 281 }
 282
 283 block_t *block_FifoShow( block_fifo_t *p_fifo )
 284 {
 285     block_t *b;
 286
 287     vlc_mutex_lock( &p_fifo->lock );
 288
 289     if( p_fifo->p_first == NULL )
 290     {
 291         vlc_cond_wait( &p_fifo->wait, &p_fifo->lock );
 292     }
 293
 294     b = p_fifo->p_first;
 295
 296     vlc_mutex_unlock( &p_fifo->lock );
 297
 298     return( b );
 299 }
 300
 301 size_t block_FifoSize( const block_fifo_t *p_fifo )
 302 {
 303     return p_fifo->i_size;
 304 }
 305
 306 size_t block_FifoCount( const block_fifo_t *p_fifo )
 307 {
 308     return p_fifo->i_depth;
 309 }