+if ( !function_exists( 'wp_text_diff' ) ) :
+/**
+ * Displays a human readable HTML representation of the difference between two strings.
+ *
+ * The Diff is available for getting the changes between versions. The output is
+ * HTML, so the primary use is for displaying the changes. If the two strings
+ * are equivalent, then an empty string will be returned.
+ *
+ * The arguments supported and can be changed are listed below.
+ *
+ * 'title' : Default is an empty string. Titles the diff in a manner compatible
+ * with the output.
+ * 'title_left' : Default is an empty string. Change the HTML to the left of the
+ * title.
+ * 'title_right' : Default is an empty string. Change the HTML to the right of
+ * the title.
+ *
+ * @since 2.6
+ * @see wp_parse_args() Used to change defaults to user defined settings.
+ * @uses Text_Diff
+ * @uses WP_Text_Diff_Renderer_Table
+ *
+ * @param string $left_string "old" (left) version of string
+ * @param string $right_string "new" (right) version of string
+ * @param string|array $args Optional. Change 'title', 'title_left', and 'title_right' defaults.
+ * @return string Empty string if strings are equivalent or HTML with differences.
+ */
+function wp_text_diff( $left_string, $right_string, $args = null ) {
+ $defaults = array( 'title' => '', 'title_left' => '', 'title_right' => '' );
+ $args = wp_parse_args( $args, $defaults );
+
+ if ( !class_exists( 'WP_Text_Diff_Renderer_Table' ) )
+ require( ABSPATH . WPINC . '/wp-diff.php' );
+
+ // Normalize whitespace
+ $left_string = trim($left_string);
+ $right_string = trim($right_string);
+ $left_string = str_replace("\r", "\n", $left_string);
+ $right_string = str_replace("\r", "\n", $right_string);
+ $left_string = preg_replace( array( '/\n+/', '/[ \t]+/' ), array( "\n", ' ' ), $left_string );
+ $right_string = preg_replace( array( '/\n+/', '/[ \t]+/' ), array( "\n", ' ' ), $right_string );
+
+ $left_lines = split("\n", $left_string);
+ $right_lines = split("\n", $right_string);
+
+ $text_diff = new Text_Diff($left_lines, $right_lines);
+ $renderer = new WP_Text_Diff_Renderer_Table();
+ $diff = $renderer->render($text_diff);
+
+ if ( !$diff )
+ return '';
+
+ $r = "<table class='diff'>\n";
+ $r .= "<col class='ltype' /><col class='content' /><col class='ltype' /><col class='content' />";
+
+ if ( $args['title'] || $args['title_left'] || $args['title_right'] )
+ $r .= "<thead>";
+ if ( $args['title'] )
+ $r .= "<tr class='diff-title'><th colspan='4'>$args[title]</th></tr>\n";
+ if ( $args['title_left'] || $args['title_right'] ) {
+ $r .= "<tr class='diff-sub-title'>\n";
+ $r .= "\t<td></td><th>$args[title_left]</th>\n";
+ $r .= "\t<td></td><th>$args[title_right]</th>\n";
+ $r .= "</tr>\n";
+ }
+ if ( $args['title'] || $args['title_left'] || $args['title_right'] )
+ $r .= "</thead>\n";
+
+ $r .= "<tbody>\n$diff\n</tbody>\n";
+ $r .= "</table>";
+
+ return $r;
+}
+endif;
+
+?>
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