1 files changed, 108 insertions, 0 deletions
diff --git a/src/YamlUnescaper.js b/src/YamlUnescaper.js
new file mode 100644
index 0000000..ea4a2c6
--- /dev/null
+++ b/src/YamlUnescaper.js
@@ -0,0 +1,108 @@
+/**
+ * YamlUnescaper encapsulates unescaping rules for single and double-quoted
+ * YAML strings.
+ *
+ * @author Matthew Lewinski <matthew@lewinski.org>
+ */
+var YamlUnescaper = function(){};
+YamlUnescaper.prototype =
+{
+	/**
+	 * Unescapes a single quoted string.
+	 *
+	 * @param string value A single quoted string.
+	 *
+	 * @return string The unescaped string.
+	 */
+	unescapeSingleQuotedString: function(value)
+	{
+		return value.replace(/''/g, "'");
+	},
+
+	/**
+	 * Unescapes a double quoted string.
+	 *
+	 * @param string value A double quoted string.
+	 *
+	 * @return string The unescaped string.
+	 */
+	unescapeDoubleQuotedString: function(value)
+	{
+		var callback = function(m) {
+			return new YamlUnescaper().unescapeCharacter(m);
+		};
+
+		// evaluate the string
+		return value.replace(new RegExp(YamlUnescaper.REGEX_ESCAPED_CHARACTER, 'g'), callback);
+	},
+
+	/**
+	 * Unescapes a character that was found in a double-quoted string
+	 *
+	 * @param string value An escaped character
+	 *
+	 * @return string The unescaped character
+	 */
+	unescapeCharacter: function(value)
+	{
+		switch (value.charAt(1)) {
+			case '0':
+				return String.fromCharCode(0);
+			case 'a':
+				return String.fromCharCode(7);
+			case 'b':
+				return String.fromCharCode(8);
+			case 't':
+				return "\t";
+			case "\t":
+				return "\t";
+			case 'n':
+				return "\n";
+			case 'v':
+				return String.fromCharCode(11);
+			case 'f':
+				return String.fromCharCode(12);
+			case 'r':
+				return String.fromCharCode(13);
+			case 'e':
+				return "\x1b";
+			case ' ':
+				return ' ';
+			case '"':
+				return '"';
+			case '/':
+				return '/';
+			case '\\':
+				return '\\';
+			case 'N':
+				// U+0085 NEXT LINE
+				return "\x00\x85";
+			case '_':
+				// U+00A0 NO-BREAK SPACE
+				return "\x00\xA0";
+			case 'L':
+				// U+2028 LINE SEPARATOR
+				return "\x20\x28";
+			case 'P':
+				// U+2029 PARAGRAPH SEPARATOR
+				return "\x20\x29";
+			case 'x':
+				return this.pack('n', new YamlInline().hexdec(value.substr(2, 2)));
+			case 'u':
+				return this.pack('n', new YamlInline().hexdec(value.substr(2, 4)));
+			case 'U':
+				return this.pack('N', new YamlInline().hexdec(value.substr(2, 8)));
+		}
+	},
+	
+	/**
+	 * @see http://phpjs.org/functions/pack
+	 * @warning only modes used above copied
+	 */
+	 pack: function(B){var g=0,o=1,m="",l="",z=0,p=[],E,s,C,I,h,c;var d,b,x,H,u,e,A,q,D,t,w,a,G,F,y,v,f;while(g<B.length){E=B.charAt(g);s="";g++;while((g<B.length)&&(B.charAt(g).match(/[\d\*]/)!==null)){s+=B.charAt(g);g++}if(s===""){s="1"}switch(E){case"n":if(s==="*"){s=arguments.length-o}if(s>(arguments.length-o)){throw new Error("Warning:  pack() Type "+E+": too few arguments")}for(z=0;z<s;z++){m+=String.fromCharCode(arguments[o]>>8&255);m+=String.fromCharCode(arguments[o]&255);o++}break;case"N":if(s==="*"){s=arguments.length-o}if(s>(arguments.length-o)){throw new Error("Warning:  pack() Type "+E+": too few arguments")}for(z=0;z<s;z++){m+=String.fromCharCode(arguments[o]>>24&255);m+=String.fromCharCode(arguments[o]>>16&255);m+=String.fromCharCode(arguments[o]>>8&255);m+=String.fromCharCode(arguments[o]&255);o++}break;default:throw new Error("Warning:  pack() Type "+E+": unknown format code")}}if(o<arguments.length){throw new Error("Warning: pack(): "+(arguments.length-o)+" arguments unused")}return m}
+}
+
+// Regex fragment that matches an escaped character in a double quoted
+// string.
+// why escape quotes, ffs!
+YamlUnescaper.REGEX_ESCAPED_CHARACTER = '\\\\([0abt\tnvfre "\\/\\\\N_LP]|x[0-9a-fA-F]{2}|u[0-9a-fA-F]{4}|U[0-9a-fA-F]{8})';