Base64 conversion code.

Not explained.

Static
Char base64encodingtable [64] = {

'A', 'B', 'C', 'D', 'E', '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', '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', '+ ','/'

};

+ (Nsstring *) base64stringfromdata: (nsdata *) Data Length: (INT) length {

Unsigned
Long ixtext, lentext;

Long ctremaining;

Unsigned
Char input [3], output [4];

Short I, charsonline = 0, ctcopy;

Const
Unsigned char * Raw;

Nsmutablestring * result;

Lentext = [Data Length];

If (lentext <1)

Return
@"";

Result = [nsmutablestring stringwithcapacity: lentext];

Raw = [data bytes];

Ixtext = 0;

While (true ){

Ctremaining = lentext-ixtext;

If (ctremaining <= 0)

Break;

For (I = 0; I <3; I ++ ){

Unsigned
Long IX = ixtext + I;

If (IX <lentext)

Input [I] = raw [ix];

Else

Input [I] = 0;

}

Output [0] = (input [0] & 0xfc)> 2;

Output [1] = (input [0] & 0x03) <4) | (input [1] & 0xf0)> 4 );

Output [2] = (input [1] & 0x0f) <2) | (input [2] & 0xc0)> 6 );

Output [3] = input [2] & 0x3f;

Ctcopy = 4;

Switch (ctremaining ){

Case 1:

Ctcopy = 2;

Break;

Case 2:

Ctcopy = 3;

Break;

}

For (I = 0; I <ctcopy; I ++)

[Result appendstring: [nsstring stringwithformat:
@ "% C", base64encodingtable [Output [I];

For (I = ctcopy; I <4; I ++)

[Result appendstring:
@ "="];

Ixtext + = 3;

Charsonline + = 4;

If (length> 0) & (charsonline> = length ))

Charsonline = 0;

}

Return result;

}