diff --git a/lib/parser_inline.js b/lib/parser_inline.js
index abc4edd..cd30260 100644
--- a/lib/parser_inline.js
+++ b/lib/parser_inline.js
@@ -61,18 +61,18 @@ ParserInline.prototype.rulesUpdate = function () {
 // returns `true` if any rule reported success
 //
 ParserInline.prototype.skipToken = function (state) {
-  var i, pos = state.pos,
+  var i, cached_pos, pos = state.pos,
       rules = this._rules,
       len = this._rules.length;
 
-  if (state.cache[pos] !== undefined) {
-    state.pos = state.cache[pos];
+  if ((cached_pos = state.cacheGet(pos)) > 0) {
+    state.pos = cached_pos;
     return true;
   }
 
   for (i = 0; i < len; i++) {
     if (rules[i](state, true)) {
-      state.cache[pos] = state.pos;
+      state.cacheSet(pos, state.pos);
       return true;
     }
   }
diff --git a/lib/rules_inline/state_inline.js b/lib/rules_inline/state_inline.js
index 723833e..5a85bb0 100644
--- a/lib/rules_inline/state_inline.js
+++ b/lib/rules_inline/state_inline.js
@@ -15,7 +15,7 @@ function StateInline(src, parser, options, env) {
   this.pending = '';
   this.pendingLevel = 0;
 
-  this.cache = {};        // Stores { start: end } pairs. Useful for backtrack
+  this.cache = [];        // Stores { start: end } pairs. Useful for backtrack
                           // optimization of pairs parse (emphasis, strikes).
 
   // Link parser state vars
@@ -34,6 +34,8 @@ function StateInline(src, parser, options, env) {
 }
 
 
+// Flush pending text
+//
 StateInline.prototype.pushPending = function () {
   this.tokens.push({
     type: 'text',
@@ -43,6 +45,10 @@ StateInline.prototype.pushPending = function () {
   this.pending = '';
 };
 
+
+// Push new token to "stream".
+// If pending text exists - flush it as text token
+//
 StateInline.prototype.push = function (token) {
   if (this.pending) {
     this.pushPending();
@@ -53,4 +59,24 @@ StateInline.prototype.push = function (token) {
 };
 
 
+// Store value to cache.
+// !!! Implementation has parser-specific optimizations
+// !!! keys MUST be integer, >= 0; values MUST be integer, > 0
+//
+StateInline.prototype.cacheSet = function (key, val) {
+  for (var i = this.cache.length; i <= key; i++) {
+    this.cache.push(0);
+  }
+
+  this.cache[key] = val;
+};
+
+
+// Get cache value
+//
+StateInline.prototype.cacheGet = function (key) {
+  return key < this.cache.length ? this.cache[key] : 0;
+};
+
+
 module.exports = StateInline;