fixing performance bug (see #64) in PHP implementation

Author: getify

minify.json.php

@@ -1,7 +1,7 @@
 <?php
 
 /*! JSON.minify()
-	v0.1 (c) Kyle Simpson
+	v2.0 (c) Kyle Simpson
 	MIT License
 */
 
@@ -10,7 +10,7 @@ function json_minify($json) {
 	$in_string = false;
 	$in_multiline_comment = false;
 	$in_singleline_comment = false;
-	$tmp; $tmp2; $new_str = array(); $ns = 0; $from = 0; $lc; $rc; $lastIndex = 0;
+	$tmp; $tmp2; $new_str = array(); $ns = 0; $from = 0; $prevFrom = 0; $lc; $rc; $lastIndex = 0;
 
 	while (preg_match($tokenizer,$json,$tmp,PREG_OFFSET_CAPTURE,$lastIndex)) {
 		$tmp = $tmp[0];
@@ -24,10 +24,11 @@ function json_minify($json) {
 			}
 			$new_str[] = $tmp2;
 		}
+		$prevFrom = $from;
 		$from = $lastIndex;
 
 		if ($tmp[0] == "\"" && !$in_multiline_comment && !$in_singleline_comment) {
-			preg_match("/(\\\\)*$/",$lc,$tmp2);
+			preg_match("/(\\\\)*$/",$lc,$tmp2,PREG_PATTERN_ORDER,$prevFrom);
 			if (!$in_string || !$tmp2 || (strlen($tmp2[0]) % 2) == 0) {	// start of string with ", or unescaped " character found to end string
 				$in_string = !$in_string;
 			}
@@ -54,4 +55,4 @@ function json_minify($json) {
 	return implode("",$new_str);
 }
 
-?>
+?>