path: root/library/cryptojs/components/enc-utf16.js

/*
CryptoJS v3.1.2
code.google.com/p/crypto-js
(c) 2009-2013 by Jeff Mott. All rights reserved.
code.google.com/p/crypto-js/wiki/License
*/
(function () {
    // Shortcuts
    var C = CryptoJS;
    var C_lib = C.lib;
    var WordArray = C_lib.WordArray;
    var C_enc = C.enc;

    /**
     * UTF-16 BE encoding strategy.
     */
    var Utf16BE = C_enc.Utf16 = C_enc.Utf16BE = {
        /**
         * Converts a word array to a UTF-16 BE string.
         *
         * @param {WordArray} wordArray The word array.
         *
         * @return {string} The UTF-16 BE string.
         *
         * @static
         *
         * @example
         *
         *     var utf16String = CryptoJS.enc.Utf16.stringify(wordArray);
         */
        stringify: function (wordArray) {
            // Shortcuts
            var words = wordArray.words;
            var sigBytes = wordArray.sigBytes;

            // Convert
            var utf16Chars = [];
            for (var i = 0; i < sigBytes; i += 2) {
                var codePoint = (words[i >>> 2] >>> (16 - (i % 4) * 8)) & 0xffff;
                utf16Chars.push(String.fromCharCode(codePoint));
            }

            return utf16Chars.join('');
        },

        /**
         * Converts a UTF-16 BE string to a word array.
         *
         * @param {string} utf16Str The UTF-16 BE string.
         *
         * @return {WordArray} The word array.
         *
         * @static
         *
         * @example
         *
         *     var wordArray = CryptoJS.enc.Utf16.parse(utf16String);
         */
        parse: function (utf16Str) {
            // Shortcut
            var utf16StrLength = utf16Str.length;

            // Convert
            var words = [];
            for (var i = 0; i < utf16StrLength; i++) {
                words[i >>> 1] |= utf16Str.charCodeAt(i) << (16 - (i % 2) * 16);
            }

            return WordArray.create(words, utf16StrLength * 2);
        }
    };

    /**
     * UTF-16 LE encoding strategy.
     */
    C_enc.Utf16LE = {
        /**
         * Converts a word array to a UTF-16 LE string.
         *
         * @param {WordArray} wordArray The word array.
         *
         * @return {string} The UTF-16 LE string.
         *
         * @static
         *
         * @example
         *
         *     var utf16Str = CryptoJS.enc.Utf16LE.stringify(wordArray);
         */
        stringify: function (wordArray) {
            // Shortcuts
            var words = wordArray.words;
            var sigBytes = wordArray.sigBytes;

            // Convert
            var utf16Chars = [];
            for (var i = 0; i < sigBytes; i += 2) {
                var codePoint = swapEndian((words[i >>> 2] >>> (16 - (i % 4) * 8)) & 0xffff);
                utf16Chars.push(String.fromCharCode(codePoint));
            }

            return utf16Chars.join('');
        },

        /**
         * Converts a UTF-16 LE string to a word array.
         *
         * @param {string} utf16Str The UTF-16 LE string.
         *
         * @return {WordArray} The word array.
         *
         * @static
         *
         * @example
         *
         *     var wordArray = CryptoJS.enc.Utf16LE.parse(utf16Str);
         */
        parse: function (utf16Str) {
            // Shortcut
            var utf16StrLength = utf16Str.length;

            // Convert
            var words = [];
            for (var i = 0; i < utf16StrLength; i++) {
                words[i >>> 1] |= swapEndian(utf16Str.charCodeAt(i) << (16 - (i % 2) * 16));
            }

            return WordArray.create(words, utf16StrLength * 2);
        }
    };

    function swapEndian(word) {
        return ((word << 8) & 0xff00ff00) | ((word >>> 8) & 0x00ff00ff);
    }
}());