Lua to BlitzMax conversion.

BlitzMax Forums/BlitzMax Programming/Lua to BlitzMax conversion.

Thareh

(Posted 2009) [#1]

Hi!
I'm trying to convert some Lua code to BlitzMax but I can't get it to work :/
This is what I've got so far:

Lua

function Scanner.mask(text)
	if Scanner.masked ~= true then
		return text;
	end
	local mask = mod(string.reverse(Scanner.scantime)+Scanner.offset,59)..Scanner.list["player"];
	local masked = "";
	local textlen = string.len(text);
	local masklen = string.len(mask);
	Scanner.offset = Scanner.offset+3;
	for i=1,textlen do
		local j = mod(i,masklen);
		local k = bit.bxor(string.byte(text,i,i),string.byte(mask,j,j));
		masked = masked..string.char(k);
	end
	return masked;
end

BlitzMax

	Function Crypt:String( Text:String )
		If Enabled = 0
			Return Text
		EndIf
		Local Mask:String = ((Int(ReverseString( ScanTime )) + Offset) Mod 59) + TChar.Name
		Local Masked:String = ""
		Local TextLen:Int = Len( Text )
		Local MaskLen:Int = Len( Mask )
		Offset = Offset + 3
		For Local I:Int = 1 To TextLen
			Local J:Int = I Mod MaskLen
			Local K:Int = StringToByte( Text, I, I ) ~ StringToByte( Mask, J, J )
			Masked = Masked +  Chr(K)
		Next
		Return Masked
		
	End Function
	
	Function ReverseString:String( Str:String )
		Local N:Int
		Local RS:String
		For N = 0 To Str.length - 1
			RS:+ Chr( Str[ Str.Length -1 -N ] )
		Next
		Return RS
	EndFunction
	
	Function StringToByte:Int( Text:String, Pos:Int, Pos2:Int )
		Local ByteStr:String
		Local Size:Int = Max( Pos - Pos2, 1 )
		For Local X:Int = 1 To Size
			ByteStr = ByteStr + Asc( Mid( Text, Pos + X - 1, 1 ) )
		Next
		Return Int( ByteStr )
	End Function

I've tried almost everything to get it working :P
Anyone have a clue?
Thank you! :)

N	(Posted 2009) [#2]

Could you explain what's wrong and possibly include any global variables you're using in the BMax code as well?

Edit: Far as I can tell - and I can't tell much, since I just had a cavity filled and my jaw is aching and the pounding won't stop - but you're forgetting to add 1 to the remainder j.

E.g.,

Scanner = {
	masked = true;
	scantime = 0;
	offset = 0;
	list = {
		player="what"
	};
}

function Scanner.mask(text)
	if not Scanner.masked then
		return text
	end
	
	local mask = ((string.reverse(Scanner.scantime) + Scanner.offset) % 59) .. Scanner.list["player"]
	local masked = ""
	local masklen = #mask
	
	Scanner.offset = Scanner.offset + 3
	
	for i=1,#text do
		local j = (i % masklen) + 1
		local k = bit.bxor(string.byte(text, i), string.byte(mask, j))
		
		masked = masked..string.char(k)
	end
	
	return masked
end

Thareh

(Posted 2009) [#3]

Thanks Nilium, But I'm trying to convert the Lua code to BlitzMax, not the other way around ^^
I just wanted to see if anyone could see a problem with my code just by looking at it.
My code works for the first characters in a string, but then it just gets strange.

One strange thing I can't get my head around is that in the Lua function, the Masked variable, which will get returned is longer than the Text variable which is what you input.
So I guess that my StringToByte function doesn't work exactly as the Lua function String.Byte does :P

Thareh

(Posted 2009) [#4]

type TCrypt
	Global ScanTime:Int = 48
	Global Offset:Int = 0
	Global Enabled:Int = 1
	
	Function Crypt:String( Text:String )
		If Enabled = 0
			Return Text
		EndIf

		Local Mask:String = ((Int( ReverseString( ScanTime ) ) + Offset) Mod 59) + TChar.Name
		Local Masked:String = ""
		Local TextLen:Int = Len( Text )
		Local MaskLen:Int = Len( Mask )
		Offset = Offset + 3
		For Local I:Int = 1 To TextLen
			Local J:Int = I Mod MaskLen
			Local K:Int = StringToByte( Text, I, I ) ~ StringToByte( Mask, J, J )
			Print K + "	" + Mid( Text, I, 1 ) + "	" + I + "	" + Chr(K)
			Masked = Masked +  Chr(K)
		Next
		Return Masked
		
	End Function
	
	Function ReverseString:String( Str:String )
		Local N:Int
		Local RS:String
		For N = 0 To Str.length - 1
			RS:+ Chr( Str[ Str.Length -1 -N ] )
		Next
		Return RS
	EndFunction
	
	Function StringToByte:Int( Text:String, Pos:Int, Pos2:Int )
		
		Local ByteStr:String
		Local Size:Int = Max( Pos - Pos2, 1 )
		For Local X:Int = 1 To Size
			ByteStr = ByteStr + Asc( Mid( Text, Pos + X - 1, 1 ) )
		Next
		Return Int( ByteStr )
		
	End Function
End Type

TCrypt.Crypt( "VanderjacktVanderjacktVanderjackt" )
Is supposed to turn out as: "dT8 \n=a\\Q37dWG<\000\r"
But it turns out as: "dT8
=ž\Q37›WG<
"