Jquery Base64源碼__Jquery

拷一份jquery base64的源碼。

/*! * jquery.base64.js 0.1 - https://github.com/yckart/jquery.base64.js * Makes Base64 en & -decoding simpler as it is. * * Based upon: https://gist.github.com/Yaffle/1284012 * * Copyright (c) 2012 Yannick Albert (http://yckart.com) * Licensed under the MIT license (http://www.opensource.org/licenses/mit-license.php). * 2013/02/10 **/;(function($) {    var b64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/",        a256 = '',        r64 = [256],        r256 = [256],        i = 0;    var UTF8 = {        /**         * Encode multi-byte Unicode string into utf-8 multiple single-byte characters         * (BMP / basic multilingual plane only)         *         * Chars in range U+0080 - U+07FF are encoded in 2 chars, U+0800 - U+FFFF in 3 chars         *         * @param {String} strUni Unicode string to be encoded as UTF-8         * @returns {String} encoded string         */        encode: function(strUni) {            // use regular expressions & String.replace callback function for better efficiency            // than procedural approaches            var strUtf = strUni.replace(/[\u0080-\u07ff]/g, // U+0080 - U+07FF => 2 bytes 110yyyyy, 10zzzzzz            function(c) {                var cc = c.charCodeAt(0);                return String.fromCharCode(0xc0 | cc >> 6, 0x80 | cc & 0x3f);            })            .replace(/[\u0800-\uffff]/g, // U+0800 - U+FFFF => 3 bytes 1110xxxx, 10yyyyyy, 10zzzzzz            function(c) {                var cc = c.charCodeAt(0);                return String.fromCharCode(0xe0 | cc >> 12, 0x80 | cc >> 6 & 0x3F, 0x80 | cc & 0x3f);            });            return strUtf;        },        /**         * Decode utf-8 encoded string back into multi-byte Unicode characters         *         * @param {String} strUtf UTF-8 string to be decoded back to Unicode         * @returns {String} decoded string         */        decode: function(strUtf) {            // note: decode 3-byte chars first as decoded 2-byte strings could appear to be 3-byte char!            var strUni = strUtf.replace(/[\u00e0-\u00ef][\u0080-\u00bf][\u0080-\u00bf]/g, // 3-byte chars            function(c) { // (note parentheses for precence)                var cc = ((c.charCodeAt(0) & 0x0f) << 12) | ((c.charCodeAt(1) & 0x3f) << 6) | (c.charCodeAt(2) & 0x3f);                return String.fromCharCode(cc);            })            .replace(/[\u00c0-\u00df][\u0080-\u00bf]/g, // 2-byte chars            function(c) { // (note parentheses for precence)                var cc = (c.charCodeAt(0) & 0x1f) << 6 | c.charCodeAt(1) & 0x3f;                return String.fromCharCode(cc);            });            return strUni;        }    };    while(i < 256) {        var c = String.fromCharCode(i);        a256 += c;        r256[i] = i;        r64[i] = b64.indexOf(c);        ++i;    }    function code(s, discard, alpha, beta, w1, w2) {        s = String(s);        var buffer = 0,            i = 0,            length = s.length,            result = '',            bitsInBuffer = 0;        while(i < length) {            var c = s.charCodeAt(i);            c = c < 256 ? alpha[c] : -1;            buffer = (buffer << w1) + c;            bitsInBuffer += w1;            while(bitsInBuffer >= w2) {                bitsInBuffer -= w2;                var tmp = buffer >> bitsInBuffer;                result += beta.charAt(tmp);                buffer ^= tmp << bitsInBuffer;            }            ++i;        }        if(!discard && bitsInBuffer > 0) result += beta.charAt(buffer << (w2 - bitsInBuffer));        return result;    }    var Plugin = $.base64 = function(dir, input, encode) {            return input ? Plugin[dir](input, encode) : dir ? null : this;        };    Plugin.btoa = Plugin.encode = function(plain, utf8encode) {        plain = Plugin.raw === false || Plugin.utf8encode || utf8encode ? UTF8.encode(plain) : plain;        plain = code(plain, false, r256, b64, 8, 6);        return plain + '===='.slice((plain.length % 4) || 4);    };    Plugin.atob = Plugin.decode = function(coded, utf8decode) {        coded = String(coded).split('=');        var i = coded.length;        do {--i;            coded[i] = code(coded[i], true, r64, a256, 6, 8);        } while (i > 0);        coded = coded.join('');        return Plugin.raw === false || Plugin.utf8decode || utf8decode ? UTF8.decode(coded) : coded;    };}(jQuery));