Convert unicode octal sequence to Javascript usable string

decode-octal-escape-sequence.js

/**
 * An Octal Escape Sequence looks like this \345\225\206
 * The unicode hex value is 0xE5 0x95 0x86
 * The octal value 345 is hexal value E5
 * The octal value 225 is hexal value 95
 * The octal value 206 is hexal value 86
 * This function converts octal values to hexal values first 
 * Then join the hexal values into an url escape code %E5%95%86, 
 * which HTML/Javascript is able to output properly
 * WARNING: not the safest method. If the string has \xxx but not 
 * part of the octal escape sequence, result will not be correct. 
 * The chance of this happening is very low, but possible.
 **/
function decode_octal(input){
    var oct_to_hex = function (oct) {
        // Converts \345 into %E5
        // Supposed to be an inline function, or lambda but I don't know how to write in JS (not interested) 
        var hex = parseInt(oct.substr(1), 8).toString(16);

        if (hex.length == 1) {
            hex = '0' + hex;
        }
        return '%' + hex.toUpperCase();
    };

    // look for \xxx 
    var temp = input.match(/\\\d{3}/g);

    if (temp === null||temp.length<3) {
        return input
    }

    for (var i = 0; i < temp.length / 3; i++) {
        if (i * 3 + 2 > temp.length) {
            break;
        }
        var c1 = temp[i * 3];
        var c2 = temp[i * 3 + 1];
        var c3 = temp[i * 3 + 2];
        var uc = oct_to_hex(c1) + oct_to_hex(c2) + oct_to_hex(c3);
        input = input.replace(c1 + c2 + c3, uc);
    }

    return decodeURI(input);
}
// An example
decode_octal('\345\225\206\351\207\217');