diff --git a/benchmark/profile.js b/benchmark/profile.js
index e553aa1..d7a191d 100755
--- a/benchmark/profile.js
+++ b/benchmark/profile.js
@@ -6,10 +6,14 @@ var fs = require('fs');
 var path = require('path');
 var Remarkable = require('../');
 
-var md = new Remarkable('commonmark');
+var md = new Remarkable({
+  html: true,
+  linkify: true,
+  typographer: true
+});
 
 var data = fs.readFileSync(path.join(__dirname, '/samples/lorem1.txt'), 'utf8');
 
-for (var i = 0; i < 20000; i++) {
+for (var i = 0; i < 200; i++) {
   md.render(data);
 }
diff --git a/lib/rules_block/lheading.js b/lib/rules_block/lheading.js
index 42a1ffb..733c828 100644
--- a/lib/rules_block/lheading.js
+++ b/lib/rules_block/lheading.js
@@ -17,6 +17,8 @@ module.exports = function lheading(state, startLine, endLine, silent) {
   pos = state.bMarks[next] + state.tShift[next];
   max = state.eMarks[next];
 
+  if (pos >= max) { return false; }
+
   marker = state.src.charCodeAt(pos);
 
   if (marker !== 0x2D/* - */ && marker !== 0x3D/* = */) { return false; }
diff --git a/lib/typographer.js b/lib/typographer.js
index db53161..c5525b2 100644
--- a/lib/typographer.js
+++ b/lib/typographer.js
@@ -20,6 +20,8 @@ rules.push(require('./rules_typographer/smartquotes'));
 
 
 function Typographer() {
+  this._rules = [];
+
   this.options  = assign({}, defaults);
 
   this.ruler = new Ruler(this.rulesUpdate.bind(this));