[javascript] UTF-8 을 고려한 js base64 encode / js base64 decode

var Base64={
    _keyStr:“ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=”,
    encode:function(e) {
        var t=“”;
        var n,r,i,s,o,u,a;
        var f=0;
        e=Base64._utf8_encode(e);
        
        while (f<e.length) {
            n=e.charCodeAt(f++);
            r=e.charCodeAt(f++);
            i=e.charCodeAt(f++);
            s=n>>2;
            o=(n&3)<<4|r>>4;
            u=(r&15)<<2|i>>6;
            a=i&63;
            
            if (isNaN(r)) {
                u=a=64;
            } else if(isNaN(i)) {
                a=64;
            }
            
            t=t+this._keyStr.charAt(s) + this._keyStr.charAt(o) + this._keyStr.charAt(u) + this._keyStr.charAt(a);
        }
            
        return t;
    },
    decode:function(e) {
        var t=“”;
        var n,r,i;
        var s,o,u,a;
        var f=0;
        e=e.replace(/[^A-Za-z0-9+/=]/g,“”);
        
        while (f<e.length) {
            s=this._keyStr.indexOf(e.charAt(f++));
            o=this._keyStr.indexOf(e.charAt(f++));
            u=this._keyStr.indexOf(e.charAt(f++));
            a=this._keyStr.indexOf(e.charAt(f++));
            n=s<<2|o>>4;
            r=(o&15)<<4|u>>2;
            i=(u&3)<<6|a;
            t=t+String.fromCharCode(n);
            
            if (u!=64) {
                t=t+String.fromCharCode(r);
            }
        
            if (a!=64) {
                t=t+String.fromCharCode(i);
            }
        }
        
        t=Base64._utf8_decode(t);
        
        return t;
    },
    _utf8_encode:function(e) {
        e=e.replace(/rn/g,“n”);
        var t=“”;
        
        for (var n=0;n<e.length;n++) {
            var r=e.charCodeAt(n);
            
            if (r<128) {
                t+=String.fromCharCode(r);
            } else if(r>127&&r<2048) {
                t+=String.fromCharCode(r>>6|192);
                t+=String.fromCharCode(r&63|128);
            } else {
                t+=String.fromCharCode(r>>12|224);
                t+=String.fromCharCode(r>>6&63|128);
                t+=String.fromCharCode(r&63|128);
            }
        }
        
        return t;
    },
    _utf8_decode:function(e) {
        var t=“”;
        var n=0;
        var r=c1=c2=0;
    
        while (n<e.length) {
            r=e.charCodeAt(n);
            if (r<128) {
                t+=String.fromCharCode(r);
                n++;
            } else if (r>191&&r<224) {
                c2=e.charCodeAt(n+1);
                t+=String.fromCharCode((r&31)<<6|c2&63);
                n+=2;
            } else {
                c2=e.charCodeAt(n+1);
                c3=e.charCodeAt(n+2);
                t+=String.fromCharCode((r&15)<<12|(c2&63)<<6|c3&63);
                n+=3;
            }
        }        
        return t;
    }    
}

// 인코딩 테스트
var string = ‘Hello World!’;
var encodedString = Base64.encode(string);
console.log(encodedString); // Outputs: “SGVsbG8gV29ybGQh”

// 디코딩 테스트
var decodedString = Base64.decode(encodedString);
console.log(decodedString); // Outputs: “Hello World!”