• yEnc

  • ¶

    jshint parameters

    /*jshint curly:true, eqeqeq:true, strict:true, boss:true, laxcomma:true */

(function(attach){
	'use strict';
  • ¶

    yEnc

    A minimal yEnc [en|de]coder 

    	var yEnc = function(){
  • ¶
    Private Variables
    		var
			self = {}
		,	reserved = [0, 10, 13, 61]
		;
  • ¶
    Public Variables
    Private Methods
  • ¶

    each()

    @param obj [collection] our source collection
    @param iterator [function] the function that will be called for each element in the collection
    @param context [object] the context our iterator should operate within

    essentially copied from underscore.js

    		var each = function(obj, iterator, context) {
			var breaker = {};
			if (obj === null) { return; }
			if (Array.prototype.forEach && obj.forEach === Array.prototype.forEach) {
				obj.forEach(iterator, context);
			} else if (obj.length === +obj.length) {
				for (var i = 0, l = obj.length; i < l; i++) {
					if (iterator.call(context, obj[i], i, obj) === breaker) { return; }
				}
			} else {
				for (var key in obj) {
					if (obj.hasOwnProperty(key)) {
						if (iterator.call(context, obj[key], key, obj) === breaker) { return; }
					}
				}
			}
		};
  • ¶

    toBytes()

    @param source [array] our source UTF-8 string

    toBytes takes a UTF8 string and returns an array of bytes (as integers)

    		var toBytes = function(source) {
			var
				output = []
			,	i = 0
			,	j = 0
			,	subchar
			;
			for (; i < source.length; i++) {
				if (source.charCodeAt(i) <= 0x7F) {
					output.push(source.charCodeAt(i));
				} else {
					subchar = encodeURIComponent(source.charAt(i)).substr(1).split('%');
					for (j = 0; j < subchar.length; j++) {
						output.push(parseInt(subchar[j], 16));
					}
				}
			}
			return output;
		};
  • ¶

    fromBytes()

    @param source [array] our source array of integers

    fromBytes turns an array of bytes (as integers) into a UTF8 string

    		var fromBytes = function(source) {
			var
				output = ''
			,	i = 0
			;

			for (; i < source.length; i++) {
				if (source[i] <= 127) {
					if (source[i] === 37) {
						output += "%25";
					} else {
						output += String.fromCharCode(source[i]);
					}
				} else {
					output += "%"+ source[i].toString(16).toUpperCase();
				}
			}
			return decodeURIComponent(output);
		};
  • ¶
    Public Methods
    yEnc.encode()

    @param source [string] the source string we will be encoding

    This is our encoding method for taking a text string and encoding it into the yEnc format, the output string is a UTF-8 string

    		self.encode = function(source) {
			var
				output = ''
			,	bytes = []
			,	converted
			;

			bytes = toBytes(source);
			each(bytes, function(ele, i){
				converted = (ele + 42) % 256;
				if (reserved.indexOf(converted) < 0) {
					output += String.fromCharCode(converted);
				} else {
					converted = (converted + 64) % 256;
					output += "="+ String.fromCharCode(converted);
				}
			});

			return output;
		};
  • ¶

    yEnc.decode()

    @param source [string] the source string we will be decoding

    This is our encoding method for taking a UTF-8 text string and decoding it into the original text string

    		self.decode = function(source) {
			var
				output = []
			,	ck = false
			,	bytes = []
			,	i = 0
			,	c
			;

			for (i = 0; i < source.length; i++) {
				c = source.charCodeAt(i);
  • ¶

    ignore newlines

    				if (c === 13 || c === 10) { continue; }
  • ¶

    if we're an "=" and we haven't been flagged, set flag

    				if (c === 61 && !ck) {
					ck = true;
					continue;
				}
				if (ck) {
					ck = false;
					c = c - 64;
				}
				if (c < 42 && c > 0) {
					output.push(c + 214);
				} else {
					output.push(c - 42);
				}
			}

			return fromBytes(output);
		};

		return self;
	}();
  • ¶

    exports for various module managers

    	if (typeof define !== 'undefined' && define.amd) {
  • ¶

    require.js/amd

    		define([], function() { return yEnc; });
	} else if (typeof module !== 'undefined' && module.exports) {
  • ¶

    node.js

    		module.exports = yEnc;
	} else if (attach !== undefined) {
  • ¶

    user provided attachment

    		attach.yEnc = yEnc;
	} else {
  • ¶

    browser global

    		this.yEnc = yEnc;
	}

})();