Retrieve all instances of the specified shortcode (WordPress)

gistfile1.php

/**
 * Retrieve all instances of the specified shortcode
 *
 * @since Never
 *
 * @global array $shortcode_tags
 * @param string $tag
 * @return boolean/array
 */
function oe_filter_shortcodes( $content, $tag, $result = array() ) {

	if ( ! empty( $result ) || shortcode_exists( $tag ) ) {

		preg_match_all( '/' . get_shortcode_regex() . '/s', $content, $matches, PREG_SET_ORDER );

		if ( empty( $matches ) )
			return empty( $result ) ? false : $result;

		foreach ( $matches as $shortcode ) {

			if ( $tag === $shortcode[2] ) {

				$result[] = $shortcode[0];

				$position = strpos( $content,$shortcode[0] );

				if ( $position !== false ) {

					$length = strlen( $shortcode[0] );

					$content = substr_replace( $content, '', $position, $length );
 
				}

				return oe_filter_shortcodes( $content, $tag, $result );

			} else if ( ! empty( $shortcode[5] ) ) {

				return oe_filter_shortcodes( $shortcode[5], $tag, $result );

			}

		}

	}

	return false;

}