what and where is the issue in Base64bitEncoder.decodeToByteArray - actionscript-3

Question

Now, I do Flash Actionscript 3.0 development, I have a Base64bitEncoder class with the encodeByteArray(...) and decodeToByteArray(...) function.
but when I write the below testing code, but the byteArray.length at before Encoding and after decoding are different, could you help to see see where I wrong?
Test Sample Code as below:
var _loc_2:XML = new XML("<formXML>aaaaa</formXML>");;
var _loc_3:ByteArray;
_loc_3 = new ByteArray();
//_loc_3.endian = Endian.LITTLE_ENDIAN;
_loc_3.writeUTFBytes(_loc_2);
trace("Before Encoding Length:" + _loc_3.length);
var baseString:String = Base64bitEncoder.encodeByteArray(_loc_3);
trace(baseString);
var strArray:ByteArray = Base64bitEncoder.decodeToByteArray(baseString);
trace("After Decoding length:" + strArray.length);
The Output log as below:
Before Encoding Length:5
GFhAGFhA
After Decoding length:**6**
Why the after is 6, where I do wrong?
Base64bitEncoder source code as below:
package
{
import flash.utils.*;
public class Base64bitEncoder extends Object
{
private static const BASE64_CHARS:String = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
private static const BASE64_URL_CHARS:String = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_!";
public function Base64bitEncoder()
{
return;
}// end function
public static function encode(param1:String, param2:Boolean = false) : String
{
var _loc_3:ByteArray;
_loc_3 = new ByteArray();
_loc_3.writeUTFBytes(param1);
return encodeByteArray(_loc_3, param2);
}// end function
public static function decodeToByteArray(param1:String, param2:Boolean = false) : ByteArray
{
var _loc_3:ByteArray;
var _loc_4:Array;
var _loc_5:Array;
var _loc_6:uint;
var _loc_7:uint;
var _loc_8:uint;
_loc_3 = new ByteArray();
_loc_4 = new Array(4);
_loc_5 = new Array(3);
_loc_6 = 0;
while (_loc_6 < param1.length)
{
// label
_loc_7 = 0;
while (_loc_7++ < 4 && _loc_6 + _loc_7 < param1.length)
{
// label
_loc_4[_loc_7] = param2 == true ? (BASE64_URL_CHARS.indexOf(param1.charAt(_loc_6 + _loc_7))) : (BASE64_CHARS.indexOf(param1.charAt(_loc_6 + _loc_7)));
}// end while
_loc_5[0] = (_loc_4[0] << 2) + ((_loc_4[1] & 48) >> 4);
_loc_5[1] = ((_loc_4[1] & 15) << 4) + ((_loc_4[2] & 60) >> 2);
_loc_5[2] = ((_loc_4[2] & 3) << 6) + _loc_4[3];
_loc_8 = 0;
while (_loc_8++ < _loc_5.length)
{
// label
if (_loc_4[_loc_8 + 1] == 64)
{
break;
}// end if
_loc_3.writeByte(_loc_5[_loc_8]);
}// end while
_loc_6 = _loc_6 + 4;
}// end while
_loc_3.position = 0;
return _loc_3;
}// end function
public static function encodeByteArray(param1:ByteArray, param2:Boolean = false) : String
{
var _loc_3:String;
var _loc_4:Array;
var _loc_5:Array;
var _loc_6:uint;
var _loc_7:uint;
var _loc_8:uint;
_loc_3 = "";
_loc_5 = new Array(4);
param1.position = 0;
while (param1.bytesAvailable > 0)
{
// label
_loc_4 = [];
_loc_6 = 0;
while (_loc_6++ < 3 && param1.bytesAvailable > 0)
{
// label
_loc_4[_loc_6] = param1.readUnsignedByte();
}// end while
_loc_5[0] = (_loc_4[0] & 252) >> 2;
_loc_5[1] = (_loc_4[0] & 3) << 4 | _loc_4[1] >> 4;
_loc_5[2] = (_loc_4[1] & 15) << 2 | _loc_4[2] >> 6;
_loc_5[3] = _loc_4[2] & 63;
_loc_7 = _loc_4.length;
while (_loc_7++ < 3)
{
// label
_loc_5[_loc_7 + 1] = 64;
}// end while
_loc_8 = 0;
while (_loc_8++ < _loc_5.length)
{
// label
_loc_3 = _loc_3 + (param2 == true ? (BASE64_URL_CHARS.charAt(_loc_5[_loc_8])) : (BASE64_CHARS.charAt(_loc_5[_loc_8])));
}// end while
}// end while
return _loc_3;
}// end function
public static function decode(param1:String, param2:Boolean = false) : String
{
var _loc_3:ByteArray;
_loc_3 = decodeToByteArray(param1, param2);
return _loc_3.readUTFBytes(_loc_3.length);
}// end function
}
}

Answer 1

#akmozo, today, I spend some time to study the base64 theory, I fix the issue, thanks.
update code:
public static function encodeByteArray(param1:ByteArray, param2:Boolean = false) : String
{
var _loc_3:String;
var _loc_4:Array;
var _loc_5:Array;
var _loc_6:uint;
var _loc_7:uint;
var _loc_8:uint;
_loc_3 = "";
_loc_5 = new Array(4);
param1.position = 0;
while (param1.bytesAvailable > 0)
{
// label
_loc_4 = [];
_loc_6 = 0;
while (_loc_6 < 3 && param1.bytesAvailable > 0)
{
// label
_loc_4[_loc_6] = param1.readUnsignedByte();
_loc_6 = _loc_6 + 1;
}// end while
_loc_5[0] = (_loc_4[0] & 252) >> 2;
_loc_5[1] = (_loc_4[0] & 3) << 4 | _loc_4[1] >> 4;
_loc_5[2] = (_loc_4[1] & 15) << 2 | _loc_4[2] >> 6;
_loc_5[3] = _loc_4[2] & 63;
/*
trace("--------------------------------");
trace("0:" + _loc_4[0]);
trace("1:" + _loc_4[1]);
trace("3:" + _loc_4[2]);
trace("len:"+_loc_4.length);
trace("++++++++++++++++++++++++++++++++");
*/
_loc_7 = _loc_4.length;
while (_loc_7 < 3)
{
// label
_loc_5[_loc_7 + 1] = 64;
_loc_7 = _loc_7 + 1;
}// end while
_loc_8 = 0;
while (_loc_8 < _loc_5.length)
{
// label
_loc_3 = _loc_3 + (param2 == true ? (BASE64_URL_CHARS.charAt(_loc_5[_loc_8])) : (BASE64_CHARS.charAt(_loc_5[_loc_8])));
_loc_8 = _loc_8 + 1;
}// end while
}// end while
return _loc_3;
}// end function
public static function decodeToByteArray(param1:String, param2:Boolean = false) : ByteArray
{
var _loc_3:ByteArray;
var _loc_4:Array;
var _loc_5:Array;
var _loc_6:uint;
var _loc_7:uint;
var _loc_8:uint;
_loc_3 = new ByteArray();
_loc_4 = new Array(4);
_loc_5 = new Array(3);
_loc_6 = 0;
while (_loc_6 < param1.length)
{
// label
_loc_7 = 0;
while (_loc_7 < 4 && _loc_6 + _loc_7 < param1.length)
{
// label
_loc_4[_loc_7] = param2 == true ? (BASE64_URL_CHARS.indexOf(param1.charAt(_loc_6 + _loc_7))) : (BASE64_CHARS.indexOf(param1.charAt(_loc_6 + _loc_7)));
_loc_7 = _loc_7 + 1;
}// end while
_loc_5[0] = (_loc_4[0] << 2) + ((_loc_4[1] & 48) >> 4);
_loc_5[1] = ((_loc_4[1] & 15) << 4) + ((_loc_4[2] & 60) >> 2);
_loc_5[2] = ((_loc_4[2] & 3) << 6) + _loc_4[3];
_loc_8 = 0;
while (_loc_8 < _loc_5.length)
{
// label
if (_loc_4[_loc_8 + 1] == 64)
{
break;
}// end if
_loc_3.writeByte(_loc_5[_loc_8]);
_loc_8 = _loc_8 + 1;
}// end while
_loc_6 = _loc_6 + 4;
}// end while
_loc_3.position = 0;
return _loc_3;
}// end function