/*
 *  call-seq:
 *     enum.minmax                   => [min,max]
 *     enum.minmax {|a,b| block }    => [min,max]
 *
 *  Returns two elements array which contains the minimum and the
 *  maximum value in the enumerable.  The first form assumes all
 *  objects implement <code>Comparable</code>; the second uses the
 *  block to return <em>a <=> b</em>.
 *
 *     a = %w(albatross dog horse)
 *     a.minmax                                  #=> ["albatross", "horse"]
 *     a.minmax {|a,b| a.length <=> b.length }   #=> ["dog", "albatross"]
 */

static VALUE
enum_minmax(VALUE obj)
{
    VALUE result[3];
    VALUE ary = rb_ary_new3(2, Qnil, Qnil);

    result[0] = Qundef;
    if (rb_block_given_p()) {
        result[2] = ary;
        rb_block_call(obj, id_each, 0, 0, minmax_ii, (VALUE)result);
    }
    else {
        rb_block_call(obj, id_each, 0, 0, minmax_i, (VALUE)result);
    }
    if (result[0] != Qundef) {
        RARRAY_PTR(ary)[0] = result[0];
        RARRAY_PTR(ary)[1] = result[1];
    }
    return ary;
}