Function get_iters

v2/engine/function.c:992–1038

 */

static void get_iters( subscript_t const subscript, LISTITER * const first,
    LISTITER * const last, int const length )
{
    int start;
    int size;
    LISTITER iter;
    LISTITER end;
    {

        if ( subscript.sub1 < 0 )
            start = length + subscript.sub1;
        else if ( subscript.sub1 > length )
            start = length;
        else
            start = subscript.sub1 - 1;

        size = subscript.sub2 < 0
            ? length + 1 + subscript.sub2 - start
            : subscript.sub2 - start;

        /*
         * HACK: When the first subscript is before the start of the list, it
         * magically becomes the beginning of the list. This is inconsistent,
         * but needed for backwards compatibility.
         */
        if ( start < 0 )
            start = 0;

        /* The "sub2 < 0" test handles the semantic error of sub2 < sub1. */
        if ( size < 0 )
            size = 0;

        if ( start + size > length )
            size = length - start;
    }

    iter = *first;
    while ( start-- > 0 )
        iter = list_next( iter );

    end = iter;
    while ( size-- > 0 )
        end = list_next( end );

    *first = iter;
    *last = end;
}

static LIST * apply_modifiers_empty( LIST * result, string * buf,
    VAR_EDITS * edits, int n )