research.m1stereo.tv/gitweb/ - melted/blob - src/framework/mlt_service.c

   1 /*
   2  * mlt_service.c -- interface for all service classes
   3  * Copyright (C) 2003-2004 Ushodaya Enterprises Limited
   4  * Author: Charles Yates <charles.yates@pandora.be>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software Foundation,
  18  * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  19  */
  20
  21 #include "config.h"
  22 #include "mlt_service.h"
  23 #include "mlt_frame.h"
  24 #include <stdio.h>
  25 #include <stdlib.h>
  26 #include <string.h>
  27
  28 /** IMPORTANT NOTES
  29
  30         The base service implements a null frame producing service - as such,
  31         it is functional without extension and will produce test cards frames
  32         and PAL sized audio frames.
  33
  34         PLEASE DO NOT CHANGE THIS BEHAVIOUR!!! OVERRIDE THE METHODS THAT
  35         CONTROL THIS IN EXTENDING CLASSES.
  36 */
  37
  38 /** Private service definition.
  39 */
  40
  41 typedef struct
  42 {
  43         int size;
  44         int count;
  45         mlt_service *in;
  46         mlt_service out;
  47 }
  48 mlt_service_base;
  49
  50 /** Private methods
  51 */
  52
  53 static void mlt_service_disconnect( mlt_service this );
  54 static void mlt_service_connect( mlt_service this, mlt_service that );
  55 static int service_get_frame( mlt_service this, mlt_frame_ptr frame, int index );
  56
  57 /** Constructor
  58 */
  59
  60 int mlt_service_init( mlt_service this, void *child )
  61 {
  62         // Initialise everything to NULL
  63         memset( this, 0, sizeof( struct mlt_service_s ) );
  64
  65         // Assign the child
  66         this->child = child;
  67
  68         // Generate local space
  69         this->local = calloc( sizeof( mlt_service_base ), 1 );
  70
  71         // Associate the methods
  72         this->get_frame = service_get_frame;
  73
  74         // Initialise the properties
  75         return mlt_properties_init( &this->parent, this );
  76 }
  77
  78 /** Connect a producer service.
  79         Returns: > 0 warning, == 0 success, < 0 serious error
  80                          1 = this service does not accept input
  81                          2 = the producer is invalid
  82                          3 = the producer is already registered with this consumer
  83 */
  84
  85 int mlt_service_connect_producer( mlt_service this, mlt_service producer, int index )
  86 {
  87         int i = 0;
  88
  89         // Get the service base
  90         mlt_service_base *base = this->local;
  91
  92         // Check if the producer is already registered with this service
  93         for ( i = 0; i < base->count; i ++ )
  94                 if ( base->in[ i ] == producer )
  95                         return 3;
  96
  97         // Allocate space
  98         if ( index >= base->size )
  99         {
 100                 int new_size = base->size + index + 10;
 101                 base->in = realloc( base->in, new_size * sizeof( mlt_service ) );
 102                 if ( base->in != NULL )
 103                 {
 104                         for ( i = base->size; i < new_size; i ++ )
 105                                 base->in[ i ] = NULL;
 106                         base->size = new_size;
 107                 }
 108         }
 109
 110         // If we have space, assign the input
 111         if ( base->in != NULL && index >= 0 && index < base->size )
 112         {
 113                 // Now we disconnect the producer service from its consumer
 114                 mlt_service_disconnect( producer );
 115
 116                 // Add the service to index specified
 117                 base->in[ index ] = producer;
 118
 119                 // Determine the number of active tracks
 120                 if ( index >= base->count )
 121                         base->count = index + 1;
 122
 123                 // Now we connect the producer to its connected consumer
 124                 mlt_service_connect( producer, this );
 125
 126                 // Inform caller that all went well
 127                 return 0;
 128         }
 129         else
 130         {
 131                 return -1;
 132         }
 133 }
 134
 135 /** Disconnect this service from its consumer.
 136 */
 137
 138 static void mlt_service_disconnect( mlt_service this )
 139 {
 140         if ( this != NULL )
 141         {
 142                 // Get the service base
 143                 mlt_service_base *base = this->local;
 144
 145                 // There's a bit more required here...
 146                 base->out = NULL;
 147         }
 148 }
 149
 150 /** Obtain the consumer this service is connected to.
 151 */
 152
 153 mlt_service mlt_service_consumer( mlt_service this )
 154 {
 155         // Get the service base
 156         mlt_service_base *base = this->local;
 157
 158         // Return the connected consumer
 159         return base->out;
 160 }
 161
 162 /** Obtain the producer this service is connected to.
 163 */
 164
 165 mlt_service mlt_service_producer( mlt_service this )
 166 {
 167         // Get the service base
 168         mlt_service_base *base = this->local;
 169
 170         // Return the connected producer
 171         return base->count > 0 ? base->in[ base->count - 1 ] : NULL;
 172 }
 173
 174 /** Associate this service to the consumer.
 175 */
 176
 177 static void mlt_service_connect( mlt_service this, mlt_service that )
 178 {
 179         if ( this != NULL )
 180         {
 181                 // Get the service base
 182                 mlt_service_base *base = this->local;
 183
 184                 // There's a bit more required here...
 185                 base->out = that;
 186         }
 187 }
 188
 189 /** Get the first connected producer service.
 190 */
 191
 192 mlt_service mlt_service_get_producer( mlt_service this )
 193 {
 194         mlt_service producer = NULL;
 195
 196         // Get the service base
 197         mlt_service_base *base = this->local;
 198
 199         if ( base->in != NULL )
 200                 producer = base->in[ 0 ];
 201
 202         return producer;
 203 }
 204
 205 /** Default implementation of get_frame.
 206 */
 207
 208 static int service_get_frame( mlt_service this, mlt_frame_ptr frame, int index )
 209 {
 210         mlt_service_base *base = this->local;
 211         if ( index < base->count )
 212         {
 213                 mlt_service producer = base->in[ index ];
 214                 if ( producer != NULL )
 215                         return mlt_service_get_frame( producer, frame, index );
 216         }
 217         *frame = mlt_frame_init( );
 218         return 0;
 219 }
 220
 221 /** Return the properties object.
 222 */
 223
 224 mlt_properties mlt_service_properties( mlt_service self )
 225 {
 226         return self != NULL ? &self->parent : NULL;
 227 }
 228
 229 /** Obtain a frame.
 230 */
 231
 232 int mlt_service_get_frame( mlt_service this, mlt_frame_ptr frame, int index )
 233 {
 234         if ( this != NULL )
 235                 return this->get_frame( this, frame, index );
 236         *frame = mlt_frame_init( );
 237         return 0;
 238 }
 239
 240 /** Close the service.
 241 */
 242
 243 void mlt_service_close( mlt_service this )
 244 {
 245         mlt_service_base *base = this->local;
 246         free( base->in );
 247         free( base );
 248         mlt_properties_close( &this->parent );
 249 }
 250