int rle_canonize( struct rle_item *begin, int length )
{
    const struct rle_item *read = begin;
    struct rle_item *write = begin;

    while ( length > 0 )
    {
        struct rle_item collapsed = *read;
        while ( --length > 0 )
        {
            ++ read;
            if ( read->value == collapsed.value )
                collapsed.count += read->count;
            else if ( read->count )
                break;
        }

        if ( collapsed.count )
            *write++ = collapsed;
    }

    return write - begin;
}