2018-06-29字节数组和字符串相互转换

function stringToByte(str) {
var bytes = new Array();
var len, c;
len = str.length;
for(var i = 0; i < len; i++) {
c = str.charCodeAt(i);
if(c >= 0x010000 && c <= 0x10FFFF) {
bytes.push(((c >> 18) & 0x07) | 0xF0);
bytes.push(((c >> 12) & 0x3F) | 0x80);
bytes.push(((c >> 6) & 0x3F) | 0x80);
bytes.push((c & 0x3F) | 0x80);
} else if(c >= 0x000800 && c <= 0x00FFFF) {
bytes.push(((c >> 12) & 0x0F) | 0xE0);
bytes.push(((c >> 6) & 0x3F) | 0x80);
bytes.push((c & 0x3F) | 0x80);
} else if(c >= 0x000080 && c <= 0x0007FF) {
bytes.push(((c >> 6) & 0x1F) | 0xC0);
bytes.push((c & 0x3F) | 0x80);
} else {
bytes.push(c & 0xFF);
}
}
return bytes;

    }


     function byteToString(arr) {
        if(typeof arr === 'string') {
            return arr;
        }
        var str = '',
            _arr = arr;
        for(var i = 0; i < _arr.length; 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;