Wikis / Unreal Wiki / Legacy:Base64

/**
	base64 encode an input array
*/
static function array<string> Base64Encode(array<string> indata, out array<string> B64Lookup)
{
	local array<string> result;
	local int i, dl, n;
	local string res;
	local array<byte> inp;
	local array<string> outp;
 
	if (B64Lookup.length != 64) Base64EncodeLookupTable(B64Lookup);
 
	// convert string to byte array
	for (n = 0; n < indata.length; n++)
	{
		res = indata[n];
		outp.length = 0;
		inp.length = 0;
		for (i = 0; i < len(res); i++)
		{
			inp[inp.length] = Asc(Mid(res, i, 1));
		}
 
		dl = inp.length;
		// fix byte array
		if ((dl%3) == 1)
		{
			inp[inp.length] = 0;
			inp[inp.length] = 0;
		}
		if ((dl%3) == 2)
		{
			inp[inp.length] = 0;
		}
		i = 0;
		while (i < dl)
		{
			outp[outp.length] = B64Lookup[(inp[i] >> 2)];
			outp[outp.length] = B64Lookup[((inp[i]&3)<<4) | (inp[i+1]>>4)];
			outp[outp.length] = B64Lookup[((inp[i+1]&15)<<2) | (inp[i+2]>>6)];
			outp[outp.length] = B64Lookup[(inp[i+2]&63)];
			i += 3;
		}
		// pad result
		if ((dl%3) == 1)
		{
			outp[outp.length-1] = "=";
			outp[outp.length-2] = "=";
		}
		if ((dl%3) == 2)
		{
			outp[outp.length-1] = "=";
		}
 
		res = "";
		for (i = 0; i < outp.length; i++)
		{
			res = res$outp[i];
		}
		result[result.length] = res;
	}
 
	return result;
}
 
/**
	Decode a base64 encoded string
*/
static function array<string> Base64Decode(array<string> indata)
{
	local array<string> result;
	local int i, dl, n, padded;
	local string res;
	local array<byte> inp;
	local array<string> outp;
 
	// convert string to byte array
	for (n = 0; n < indata.length; n++)
	{
		res = indata[n];
		outp.length = 0;
		inp.length = 0;
		padded = 0;
		for (i = 0; i < len(res); i++)
		{
			dl = Asc(Mid(res, i, 1));
			// convert base64 ascii to base64 index
			if ((dl >= 65) && (dl <= 90)) dl -= 65; // cap alpha
			else if ((dl >= 97) && (dl <= 122)) dl -= 71; // low alpha
			else if ((dl >= 48) && (dl <= 57)) dl += 4; // digits
			else if (dl == 43) dl = 62;
			else if (dl == 47) dl = 63;
			else if (dl == 61) padded++;
			inp[inp.length] = dl;
		}
 
		dl = inp.length;
		i = 0;
		while (i < dl)
		{
			outp[outp.length] = Chr((inp[i] << 2) | (inp[i+1] >> 4));
			outp[outp.length] = Chr(((inp[i+1]&15)<<4) | (inp[i+2]>>2));
			outp[outp.length] = Chr(((inp[i+2]&3)<<6) | (inp[i+3]));
			i += 4;
		}
		outp.length = outp.length-padded;
 
		res = "";
		for (i = 0; i < outp.length; i++)
		{
			res = res$outp[i];
		}
		result[result.length] = res;
	}
 
	return result;
}
 
/**
	Generate the base 64 encode lookup table
*/
static function Base64EncodeLookupTable(out array<string> LookupTable)
{
	local int i;
	for (i = 0; i < 26; i++)
	{
		LookupTable[i] = Chr(i+65);
	}
	for (i = 0; i < 26; i++)
	{
		LookupTable[i+26] = Chr(i+97);
	}
	for (i = 0; i < 10; i++)
	{
		LookupTable[i+52] = Chr(i+48);
	}
	LookupTable[62] = "+";
	LookupTable[63] = "/";
}