Function order

v2/engine/modules/order.c:88–146

LIST * order( FRAME * frame, int flags )
{
    LIST * arg = lol_get( frame->args, 0 );
    LIST * result = L0;
    int src;
    LISTITER iter = list_begin( arg );
    LISTITER const end = list_end( arg );

    /* We need to create a graph of order dependencies between the passed
     * objects. We assume there are no duplicates passed to 'add_pair'.
     */
    int length = list_length( arg );
    int * * graph = ( int * * )BJAM_CALLOC( length, sizeof( int * ) );
    int * order = ( int * )BJAM_MALLOC( ( length + 1 ) * sizeof( int ) );

    for ( src = 0; iter != end; iter = list_next( iter ), ++src )
    {
        /* For all objects this one depends upon, add elements to 'graph'. */
        LIST * dependencies = var_get( frame->module, list_item( iter ) );
        int index = 0;
        LISTITER dep_iter = list_begin( dependencies );
        LISTITER const dep_end = list_end( dependencies );

        graph[ src ] = ( int * )BJAM_CALLOC( list_length( dependencies ) + 1,
            sizeof( int ) );
        for ( ; dep_iter != dep_end; dep_iter = list_next( dep_iter ) )
        {
            int const dst = list_index( arg, list_item( dep_iter ) );
            if ( dst != -1 )
                graph[ src ][ index++ ] = dst;
        }
        graph[ src ][ index ] = -1;
    }

    topological_sort( graph, length, order );

    {
        int index = length - 1;
        for ( ; index >= 0; --index )
        {
            int i;
            LISTITER iter = list_begin( arg );
            LISTITER const end = list_end( arg );
            for ( i = 0; i < order[ index ]; ++i, iter = list_next( iter ) );
            result = list_push_back( result, object_copy( list_item( iter ) ) );
        }
    }

    /* Clean up */
    {
        int i;
        for ( i = 0; i < length; ++i )
            BJAM_FREE( graph[ i ] );
        BJAM_FREE( graph );
        BJAM_FREE( order );
    }

    return result;