Like do_shortcode() does, check to see if any of the plugin's shortcodes are in use before running the post content through regex.

Author: Viper007Bond

syntaxhighlighter.php

@@ -348,14 +348,19 @@ function output_shortcodes_for_tinymce() {
 	 *
 	 * Phew!
 	 *
-	 * @param string $content The post content.
+	 * @param string $content  The post content.
 	 * @param string $callback The callback function that should be used for add_shortcode()
 	 *
 	 * @return string The filtered content, with this plugin's shortcodes parsed.
 	 */
 	function shortcode_hack( $content, $callback ) {
 		global $shortcode_tags;
 
+		// Regex is slow. Let's do some strpos() checks first.
+		if ( ! $this->string_has_shortcodes( $content, $this->shortcodes ) ) {
+			return $content;
+		}
+
 		// Backup current registered shortcodes and clear them all out
 		$orig_shortcode_tags = $shortcode_tags;
 		remove_all_shortcodes();
@@ -382,6 +387,26 @@ function shortcode_hack( $content, $callback ) {
 	}
 
 
+	/**
+	 * A quick checker to see if any of this plugin's shortcodes are in use in a string.
+	 * Since all of the tags can't be self-closing, we look for the closing tag.
+	 *
+	 * @param string $string     The string to look through. This is a post's contents usually.
+	 * @param array  $shortcodes The array of shortcodes to look for.
+	 *
+	 * @return bool Whether any shortcode usage was found.
+	 */
+	function string_has_shortcodes( $string, $shortcodes ) {
+		foreach ( $shortcodes as $shortcode ) {
+			if ( false !== strpos( $string, "[/{$shortcode}]" ) ) {
+				return true;
+			}
+		}
+
+		return false;
+	}
+
+
 	/**
 	 * Add extra square brackets around escaped shortcodes.
 	 * This is to counteract the beginning of the do_shortcode_tag() function.