[melted] / src / framework / mlt_service.c

/*
 * mlt_service.c -- interface for all service classes
 * Copyright (C) 2003-2004 Ushodaya Enterprises Limited
 * Author: Charles Yates <charles.yates@pandora.be>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#include "config.h"
#include "mlt_service.h"
#include "mlt_frame.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

/** IMPORTANT NOTES

        The base service implements a null frame producing service - as such,
        it is functional without extension and will produce test cards frames 
        and PAL sized audio frames.

        PLEASE DO NOT CHANGE THIS BEHAVIOUR!!! OVERRIDE THE METHODS THAT 
        CONTROL THIS IN EXTENDING CLASSES.
*/

/** Private service definition.
*/

typedef struct
{
        int size;
        int count;
        mlt_service *in;
        mlt_service out;
}
mlt_service_base;

/** Private methods
*/

static void mlt_service_disconnect( mlt_service this );
static void mlt_service_connect( mlt_service this, mlt_service that );
static int service_get_frame( mlt_service this, mlt_frame_ptr frame, int index );

/** Constructor
*/

int mlt_service_init( mlt_service this, void *child )
{
        // Initialise everything to NULL
        memset( this, 0, sizeof( struct mlt_service_s ) );

        // Assign the child
        this->child = child;

        // Generate local space
        this->local = calloc( sizeof( mlt_service_base ), 1 );

        // Associate the methods
        this->get_frame = service_get_frame;
        
        // Initialise the properties
        return mlt_properties_init( &this->parent, this );
}

/** Connect a producer service.
        Returns: > 0 warning, == 0 success, < 0 serious error
                         1 = this service does not accept input
                         2 = the producer is invalid
                         3 = the producer is already registered with this consumer
*/

int mlt_service_connect_producer( mlt_service this, mlt_service producer, int index )
{
        int i = 0;

        // Get the service base
        mlt_service_base *base = this->local;

        // Check if the producer is already registered with this service
        for ( i = 0; i < base->count; i ++ )
                if ( base->in[ i ] == producer )
                        return 3;

        // Allocate space
        if ( index >= base->size )
        {
                int new_size = base->size + index + 10;
                base->in = realloc( base->in, new_size * sizeof( mlt_service ) );
                if ( base->in != NULL )
                {
                        for ( i = base->size; i < new_size; i ++ )
                                base->in[ i ] = NULL;
                        base->size = new_size;
                }
        }

        // If we have space, assign the input
        if ( base->in != NULL && index >= 0 && index < base->size )
        {
                // Now we disconnect the producer service from its consumer
                mlt_service_disconnect( producer );
                
                // Add the service to index specified
                base->in[ index ] = producer;
                
                // Determine the number of active tracks
                if ( index >= base->count )
                        base->count = index + 1;

                // Now we connect the producer to its connected consumer
                mlt_service_connect( producer, this );

                // Inform caller that all went well
                return 0;
        }
        else
        {
                return -1;
        }
}

/** Disconnect this service from its consumer.
*/

static void mlt_service_disconnect( mlt_service this )
{
        // Get the service base
        mlt_service_base *base = this->local;

        // There's a bit more required here...
        base->out = NULL;
}

/** Associate this service to the its consumer.
*/

static void mlt_service_connect( mlt_service this, mlt_service that )
{
        // Get the service base
        mlt_service_base *base = this->local;

        // There's a bit more required here...
        base->out = that;
}

/** Get the first connected producer service.
*/

mlt_service mlt_service_get_producer( mlt_service this )
{
        mlt_service producer = NULL;

        // Get the service base
        mlt_service_base *base = this->local;

        if ( base->in != NULL )
                producer = base->in[ 0 ];
        
        return producer;
}

/** Default implementation of get_frame.
*/

static int service_get_frame( mlt_service this, mlt_frame_ptr frame, int index )
{
        mlt_service_base *base = this->local;
        if ( index < base->count )
        {
                mlt_service producer = base->in[ index ];
                if ( producer != NULL )
                        return mlt_service_get_frame( producer, frame, index );
        }
        *frame = mlt_frame_init( );
        return 0;
}

/** Return the properties object.
*/

mlt_properties mlt_service_properties( mlt_service self )
{
        return &self->parent;
}

/** Obtain a frame.
*/

int mlt_service_get_frame( mlt_service this, mlt_frame_ptr frame, int index )
{
        return this->get_frame( this, frame, index );
}

/** Close the service.
*/

void mlt_service_close( mlt_service this )
{
        mlt_service_base *base = this->local;
        free( base->in );
        free( base );
        mlt_properties_close( &this->parent );
}