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;
    }
};

Answer 2

有的，你是要截图吗？还是做别的操作。

Answer 3

window.btoa 和atob

Answer 4

//字符串转byte[]
function str2Bytes(str) {
    var ch, stack, result = [];
    for (var i = 0, len = str.length; i < len; i++) {
        ch = str.charCodeAt(i);
        stack = []; 
        do {
            if (ch >= 0x010000 && ch <= 0x10FFFF) {
                stack.push(((ch >> 18) & 0x07) | 0xF0);
                stack.push(((ch >> 12) & 0x3F) | 0x80);
                stack.push(((ch >> 6) & 0x3F) | 0x80);
                stack.push((ch & 0x3F) | 0x80);
            } else if (ch >= 0x000800 && ch <= 0x00FFFF) {
                stack.push(((ch >> 12) & 0x0F) | 0xE0);
                stack.push(((ch >> 6) & 0x3F) | 0x80);
                stack.push((ch & 0x3F) | 0x80);
            } else if (ch >= 0x000080 && ch <= 0x0007FF) {
                stack.push(((ch >> 6) & 0x1F) | 0xC0);
                stack.push((ch & 0x3F) | 0x80);
            } else {
                stack.push(ch & 0xFF);
            }
            ch = ch >> 8; 
        } while (ch);
        result = result.concat(stack.reverse());
    }
    return result;
}

//byte[]转string
function bytes2Str(_arr) {
    var str = '';
    //字节序列转ASCII码
    //[0x24, 0x26, 0x28, 0x2A] ==> "$&C*"
    for (var i = 0, len = _arr.length; i < len; i++) {
        var one = _arr[i].toString(2),
        v = one.match(/^1+?(?=0)/);
        if (v && one.length == 8) {
            var bytesLength = v[0].length;
            var store = _arr[i].toString(2).slice(7 - bytesLength);
            for (var st = 1; st < bytesLength; st++) {
                store += _arr[st + i].toString(2).slice(2);
            }
            str += String.fromCharCode(parseInt(store, 2));
            i += bytesLength - 1;
        } else {
            str += String.fromCharCode(_arr[i]);
        }
    }
    return str;
}

Answer 5

//int转byte
function int2Byte(i) {
    var b = i & 0xFF; //[0-255]
    var c = 0;
    if (b >= 0x80) {
        c = b % 0x80;
        c = -1 * (0x80 - c);
    } else {
        c = b;
    }
    return c;
}

//字符串转byte[]
function str2Bytes(str) {
    var ch, stack, result = [];
    for (var i = 0, len = str.length; i < len; i++) {
        ch = str.charCodeAt(i);
        stack = []; 
        if (ch >= 0x010000 && ch <= 0x10FFFF) {
            stack.push(int2Byte(((ch >> 18) & 0x07) | 0xF0));
            stack.push(int2Byte(((ch >> 12) & 0x3F) | 0x80));
            stack.push(int2Byte(((ch >> 6) & 0x3F) | 0x80));
            stack.push(int2Byte((ch & 0x3F) | 0x80));
        } else if (ch >= 0x000800 && ch <= 0x00FFFF) {
            stack.push(int2Byte(((ch >> 12) & 0x0F) | 0xE0));
            stack.push(int2Byte(((ch >> 6) & 0x3F) | 0x80));
            stack.push(int2Byte((ch & 0x3F) | 0x80));
        } else if (ch >= 0x000080 && ch <= 0x0007FF) {
            stack.push(int2Byte(((ch >> 6) & 0x1F) | 0xC0));
            stack.push(int2Byte((ch & 0x3F) | 0x80));
        } else {
            stack.push(ch & 0xFF);
        }
        result = result.concat(stack);
    }
    return result;
}

//byte[]转string
function bytes2Str(_arr) {
    var unicodeStr = '';
    for (var pos = 0, len = _arr.length; pos < len;) {
        var flag = _arr[pos];
        var unicode = 0;
        if ((flag >>> 7) === 0) {
            unicodeStr += String.fromCharCode(_arr[pos]);
            pos += 1;
        } else if ((flag & 0xF0) === 0xF0) {
            unicode = (_arr[pos] & 0xF) << 18;
            unicode |= (_arr[pos + 1] & 0x3F) << 12;
            unicode |= (_arr[pos + 2] & 0x3F) << 6;
            unicode |= (_arr[pos + 3] & 0x3F);
            unicodeStr += String.fromCodePoint(unicode);
            pos += 4;
        } else if ((flag & 0xE0) === 0xE0) {
            unicode = (_arr[pos] & 0x1F) << 12;;
            unicode |= (_arr[pos + 1] & 0x3F) << 6;
            unicode |= (_arr[pos + 2] & 0x3F);
            unicodeStr += String.fromCharCode(unicode);
            pos += 3;
        } else if ((flag & 0xC0) === 0xC0) {
            unicode = (_arr[pos] & 0x3F) << 6;
            unicode |= (_arr[pos + 1] & 0x3F);
            unicodeStr += String.fromCharCode(unicode);
            pos += 2;
        } else {
            unicodeStr += String.fromCharCode(_arr[pos]);
            pos += 1;
        }
    }
    return unicodeStr;
}

var toBase64 = [
    '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', '+', '/'
];

var fromBase64 = new Array();
for (var i = 0, len = 256; i < len; i++) {
    fromBase64[i] = -1;
}
for (var j = 0; j < toBase64.length; j++) {
    fromBase64[toBase64[j].charCodeAt(0)] = j;
}
fromBase64['='.charCodeAt(0)] = -2;

//base64编码 string return byte[]
function encodeBase64(src) {
    src = src || '';
    var bsrc = str2Bytes(src);
    var end = bsrc.length;
    var off = 0;
    var dst = [];
    var base64 = [];
    for (var i = 0, len = toBase64.length; i < len; i++) {
        base64[i] = toBase64[i].charCodeAt(0);
    }
    var sp = off;
    var slen = Math.trunc((end - off) / 3) * 3;
    var sl = off + slen;
    var dp = 0;
    while (sp < sl) {
        var sl0 = Math.min(sp + slen, sl);
        for (var sp0 = sp, dp0 = dp; sp0 < sl0;) {
            var bits = (bsrc[sp0++] & 0xff) << 16 | (bsrc[sp0++] & 0xff) << 8 | (bsrc[sp0++] & 0xff);
            dst[dp0++] = int2Byte(base64[(bits >>> 18) & 0x3f]);
            dst[dp0++] = int2Byte(base64[(bits >>> 12) & 0x3f]);
            dst[dp0++] = int2Byte(base64[(bits >>> 6) & 0x3f]);
            dst[dp0++] = int2Byte(base64[bits & 0x3f]);
        }
        var dlen = (sl0 - sp) / 3 * 4;
        dp += dlen;
        sp = sl0;
    }
    if (sp < end) {
        var b0 = bsrc[sp++] & 0xff;
        dst[dp++] = int2Byte(base64[b0 >> 2]);
        if (sp == end) {
            dst[dp++] = int2Byte(base64[(b0 << 4) & 0x3f]);
            dst[dp++] = '='.charCodeAt(0);
            dst[dp++] = '='.charCodeAt(0);
        } else {
            var b1 = bsrc[sp++] & 0xff;
            dst[dp++] = int2Byte(base64[(b0 << 4) & 0x3f | (b1 >> 4)]);
            dst[dp++] = int2Byte(base64[(b1 << 2) & 0x3f]);
            dst[dp++] = '='.charCodeAt(0);
        }
    }
    return dst;
}

//base64解码 string return byte[]
function decodeBase64(src) {
    src = (src || '').replace(/[^A-z0-9+/]/g, '');
    var bsrc = str2Bytes(src);
    var sl = bsrc.length;
    var sp = 0;
    var dst = [];
    var base64 = fromBase64;
    var dp = 0;
    var bits = 0;
    var shiftto = 18; 
    while (sl > sp) {
        var b = bsrc[sp++] & 0xff;
        if ((b = base64[b]) < 0) {
            if (b == -2) { 
                break;
            }
        }
        bits |= (b << shiftto);
        shiftto -= 6;
        if (shiftto < 0) {
            dst[dp++] = int2Byte(bits >> 16);
            dst[dp++] = int2Byte(bits >> 8);
            dst[dp++] = int2Byte(bits);
            shiftto = 18;
            bits = 0;
        }
    }
    if (shiftto == 6) {
        dst[dp++] = int2Byte(bits >> 16);
    } else if (shiftto == 0) {
        dst[dp++] = int2Byte(bits >> 16);
        dst[dp++] = int2Byte(bits >> 8);
    }
    return dst;
}

Answer 6

搞定了