/**
 * Gets gallery attachments from post content
 *
 * @param int $post Post ID or object.
 * @return mixed False on failure, array with attachment objects on succes
 */
function get_gallery_attachments( $post = null ) {

	$post = get_post( $post );
	if ( !$post )
		return false;

	$gallery_attachments = array();
	$pattern = get_shortcode_regex();
	preg_match_all( "/$pattern/s", $post->post_content , $matches, PREG_SET_ORDER );

	if ( !empty( $matches ) ) {
		foreach ( $matches as $match ) {
			if ( $match[2] == 'gallery' ) {
				// allow [[gallery]] syntax for escaping a tag
				if ( !( $match[1] == '[' && $match[6] == ']' ) ) {

					$attr = shortcode_parse_atts( $match[3] );

					if ( ! empty( $attr['ids'] ) ) {
						// 'ids' is explicitly ordered, unless you specify otherwise.
						if ( empty( $attr['orderby'] ) )
							$attr['orderby'] = 'post__in';
						$attr['include'] = $attr['ids'];
					}

					if ( isset( $attr['orderby'] ) ) {
						$attr['orderby'] = sanitize_sql_orderby( $attr['orderby'] );
						if ( !$attr['orderby'] )
							unset( $attr['orderby'] );
					}

					$defaults = array(
						'order'      => 'ASC',
						'orderby'    => 'menu_order ID',
						'id'         => $post->ID,
						'include'    => '',
						'exclude'    => ''
					);
					$args = wp_parse_args( $attr, $defaults );
					extract( $args );
					$id = intval( $id );
					if ( 'RAND' == $order )
						$orderby = 'none';

					if ( !empty( $include ) ) {
						$_attachments = get_posts( array( 'include' => $include, 'post_status' => 'inherit', 'post_type' => 'attachment', 'post_mime_type' => 'image', 'order' => $order, 'orderby' => $orderby ) );
						$attachments = array();
						foreach ( $_attachments as $key => $val ) {
							$attachments[$val->ID] = $_attachments[$key];
						}
					} elseif ( !empty( $exclude ) ) {
						$attachments = get_children( array( 'post_parent' => $id, 'exclude' => $exclude, 'post_status' => 'inherit', 'post_type' => 'attachment', 'post_mime_type' => 'image', 'order' => $order, 'orderby' => $orderby ) );
					} else {
						$attachments = get_children( array( 'post_parent' => $id, 'post_status' => 'inherit', 'post_type' => 'attachment', 'post_mime_type' => 'image', 'order' => $order, 'orderby' => $orderby ) );
					}

					if ( !empty( $attachments ) )
						$gallery_attachments[] = $attachments;
				}
			}
		}
	}

	if ( !empty( $gallery_attachments ) )
		return $gallery_attachments;
	else
		return false;
}