Merge pull request #65 from stof/no_substr

Refactor the lexer to avoid altering the input

Author: Seldaek

src/Seld/JsonLint/Lexer.php

@@ -20,20 +20,20 @@ class Lexer
 {
     private $EOF = 1;
     private $rules = array(
-        0 => '/^\s+/',
-        1 => '/^-?([0-9]|[1-9][0-9]+)(\.[0-9]+)?([eE][+-]?[0-9]+)?\b/',
-        2 => '{^"(?>\\\\["bfnrt/\\\\]|\\\\u[a-fA-F0-9]{4}|[^\0-\x1f\\\\"]++)*+"}',
-        3 => '/^\{/',
-        4 => '/^\}/',
-        5 => '/^\[/',
-        6 => '/^\]/',
-        7 => '/^,/',
-        8 => '/^:/',
-        9 => '/^true\b/',
-        10 => '/^false\b/',
-        11 => '/^null\b/',
-        12 => '/^$/',
-        13 => '/^./',
+        0 => '/\G\s+/',
+        1 => '/\G-?([0-9]|[1-9][0-9]+)(\.[0-9]+)?([eE][+-]?[0-9]+)?\b/',
+        2 => '{\G"(?>\\\\["bfnrt/\\\\]|\\\\u[a-fA-F0-9]{4}|[^\0-\x1f\\\\"]++)*+"}',
+        3 => '/\G\{/',
+        4 => '/\G\}/',
+        5 => '/\G\[/',
+        6 => '/\G\]/',
+        7 => '/\G,/',
+        8 => '/\G:/',
+        9 => '/\Gtrue\b/',
+        10 => '/\Gfalse\b/',
+        11 => '/\Gnull\b/',
+        12 => '/\G$/',
+        13 => '/\G./',
     );
 
     private $conditions = array(
@@ -47,7 +47,7 @@ class Lexer
     private $input;
     private $more;
     private $done;
-    private $matched;
+    private $offset;
 
     public $match;
     public $yylineno;
@@ -70,8 +70,9 @@ public function setInput($input)
         $this->input = $input;
         $this->more = false;
         $this->done = false;
+        $this->offset = 0;
         $this->yylineno = $this->yyleng = 0;
-        $this->yytext = $this->matched = $this->match = '';
+        $this->yytext = $this->match = '';
         $this->conditionStack = array('INITIAL');
         $this->yylloc = array('first_line' => 1, 'first_column' => 0, 'last_line' => 1, 'last_column' => 0);
 
@@ -88,16 +89,16 @@ public function showPosition()
 
     public function getPastInput()
     {
-        $past = substr($this->matched, 0, \strlen($this->matched) - \strlen($this->match));
+        $pastLength = $this->offset - \strlen($this->match);
 
-        return (\strlen($past) > 20 ? '...' : '') . substr($past, -20);
+        return ($pastLength > 20 ? '...' : '') . substr($this->input, max(0, $pastLength - 20), min(20, $pastLength));
     }
 
     public function getUpcomingInput()
     {
         $next = $this->match;
         if (\strlen($next) < 20) {
-            $next .= substr($this->input, 0, 20 - \strlen($next));
+            $next .= substr($this->input, $this->offset, 20 - \strlen($next));
         }
 
         return substr($next, 0, 20) . (\strlen($next) > 20 ? '...' : '');
@@ -113,7 +114,7 @@ private function next()
         if ($this->done) {
             return $this->EOF;
         }
-        if ($this->input === '') {
+        if ($this->offset === \strlen($this->input)) {
             $this->done = true;
         }
 
@@ -131,7 +132,7 @@ private function next()
         $rulesLen = \count($rules);
 
         for ($i=0; $i < $rulesLen; $i++) {
-            if (preg_match($this->rules[$rules[$i]], $this->input, $match)) {
+            if (preg_match($this->rules[$rules[$i]], $this->input, $match, 0, $this->offset)) {
                 preg_match_all('/\n.*/', $match[0], $lines);
                 $lines = $lines[0];
                 if ($lines) {
@@ -148,8 +149,7 @@ private function next()
                 $this->match .= $match[0];
                 $this->yyleng = \strlen($this->yytext);
                 $this->more = false;
-                $this->input = substr($this->input, \strlen($match[0]));
-                $this->matched .= $match[0];
+                $this->offset += \strlen($match[0]);
                 $token = $this->performAction($rules[$i], $this->conditionStack[\count($this->conditionStack)-1]);
                 if ($token) {
                     return $token;
@@ -159,7 +159,7 @@ private function next()
             }
         }
 
-        if ($this->input === "") {
+        if ($this->offset === \strlen($this->input)) {
             return $this->EOF;
         }