Added support for double_encode param

Author: Rafal Kukawski

functions/strings/htmlentities.js

@@ -1,4 +1,4 @@
-function htmlentities (string, quote_style) {
+function htmlentities (string, quote_style, charset, double_encode) {
     // http://kevin.vanzonneveld.net
     // +   original by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
     // +    revised by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
@@ -8,25 +8,34 @@ function htmlentities (string, quote_style) {
     // +    revised by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
     // +    bugfixed by: Brett Zamir (http://brett-zamir.me)
     // +      input by: Ratheous
+    // +   improved by: Rafał Kukawski (http://blog.kukawski.pl)
     // -    depends on: get_html_translation_table
     // *     example 1: htmlentities('Kevin & van Zonneveld');
     // *     returns 1: 'Kevin & van Zonneveld'
     // *     example 2: htmlentities("foo'bar","ENT_QUOTES");
     // *     returns 2: 'foo'bar'
     var hash_map = {},
         symbol = '',
-        tmp_str = '',
-        entity = '';
-    tmp_str = string.toString();
+        entity = '',
+        self = this;
+    string += '';
+    double_encode = !!double_encode || double_encode == null;
 
     if (false === (hash_map = this.get_html_translation_table('HTML_ENTITIES', quote_style))) {
         return false;
     }
     hash_map["'"] = ''';
-    for (symbol in hash_map) {
-        entity = hash_map[symbol];
-        tmp_str = tmp_str.split(symbol).join(entity);
+    
+    if (double_encode) {
+        for (symbol in hash_map) {
+            entity = hash_map[symbol];
+            string = string.split(symbol).join(entity);
+        }
+    } else {
+        string = string.replace(/([\s\S]*?)(&(?:#\d+|#x[\da-f]+|[a-z][\da-z]*);|$)/g, function (ignore, text, entity) {
+            return self.htmlentities(text, quote_style, charset) + entity;
+        });
     }
 
-    return tmp_str;
+    return string;
 }