js中有没有类似java sun.misc.BASE64Decoder的Base64转字节数组

Question

各位朋友,js中有没有类似java sun.misc.BASE64Decoder的Base64转字节数组的方式？

Answer 1

if (!Shotgun)
    var Shotgun = {};
if (!Shotgun.Js)
    Shotgun.Js = {};
Shotgun.Js.Base64 = {
    _table: [
        'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
        'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f',
        'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v',
        'w', 'x', 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/'
    ],

    encode: function (bin) {
        var codes = [];
        var un = 0;
        un = bin.length % 3;
        if (un == 1)
            bin.push(0, 0);
        else if (un == 2)
            bin.push(0);
        for (var i = 2; i < bin.length; i += 3) {
            var c = bin[i - 2] << 16;
            c |= bin[i - 1] << 8;
            c |= bin[i];
            codes.push(this._table[c >> 18 & 0x3f]);
            codes.push(this._table[c >> 12 & 0x3f]);
            codes.push(this._table[c >> 6 & 0x3f]);
            codes.push(this._table[c & 0x3f]);
        }
        if (un >= 1) {
            codes[codes.length - 1] = "=";
            bin.pop();
        }
        if (un == 1) {
            codes[codes.length - 2] = "=";
            bin.pop();
        }
        return codes.join("");
    },
    decode: function (base64Str) {
        var i = 0;
        var bin = [];
        var x = 0, code = 0, eq = 0;
        while (i < base64Str.length) {
            var c = base64Str.charAt(i++);
            var idx = this._table.indexOf(c);
            if (idx == -1) {
                switch (c) {
                    case '=': idx = 0; eq++; break;
                    case ' ':
                    case '\n':
                    case "\r":
                    case '\t':
                        continue;
                    default:
                        throw { "message": "\u0062\u0061\u0073\u0065\u0036\u0034\u002E\u0074\u0068\u0065\u002D\u0078\u002E\u0063\u006E\u0020\u0045\u0072\u0072\u006F\u0072\u003A\u65E0\u6548\u7F16\u7801\uFF1A" + c };
                }
            }
            if (eq > 0 && idx != 0)
                throw { "message": "\u0062\u0061\u0073\u0065\u0036\u0034\u002E\u0074\u0068\u0065\u002D\u0078\u002E\u0063\u006E\u0020\u0045\u0072\u0072\u006F\u0072\u003A\u7F16\u7801\u683C\u5F0F\u9519\u8BEF\uFF01" };

            code = code << 6 | idx;
            if (++x != 4)
                continue;
            bin.push(code >> 16);
            bin.push(code >> 8 & 0xff);
            bin.push(code & 0xff)
            code = x = 0;
        }
        if (code != 0)
            throw { "message": "\u0062\u0061\u0073\u0065\u0036\u0034\u002E\u0074\u0068\u0065\u002D\u0078\u002E\u0063\u006E\u0020\u0045\u0072\u0072\u006F\u0072\u003A\u7F16\u7801\u6570\u636E\u957F\u5EA6\u9519\u8BEF" };
        if (eq == 1)
            bin.pop();
        else if (eq == 2) {
            bin.pop();
            bin.pop();
        } else if (eq > 2)
            throw { "message": "\u0062\u0061\u0073\u0065\u0036\u0034\u002E\u0074\u0068\u0065\u002D\u0078\u002E\u0063\u006E\u0020\u0045\u0072\u0072\u006F\u0072\u003A\u7F16\u7801\u683C\u5F0F\u9519\u8BEF\uFF01" };


        for (var i=0;i<bin.length;i++){
            if (bin[i]>=128){
                bin[i]=bin[i]-256;
            }
        }

        return bin;
    }
};