4 bytes to blitzmax int

BlitzMax Forums/BlitzMax Programming/4 bytes to blitzmax int

Retimer

(Posted 2009) [#1]

I'm working with flash-based sockets, with a blitzmax-based server.

Reading an int in flash does not read the integers sent by "writeint" properly, so i'm trying to get a function in flash to read the 4 bytes sent by the server, and convert it into a blitzmax based int.

I figured blitzmax writes an int using bytes something like this:

int_from_bytes(0,0,0,1)

Function Int_From_Bytes(b3:Byte,b2:Byte,b1:Byte,b0:Byte)
	Print (((((b3 Shl 8) + b2) Shl 8) + b1) Shl 8) + b0
End Function

but I don't quite have it. Any clues?

_Skully

(Posted 2009) [#2]

according to the stream mod its more about how its stored than how its written...

	Method WriteInt( n )
		Local q:Int=n
		WriteBytes Varptr q,4
	End Method

you could just create your own int write routine that mirrors the flash storage method

Floyd

(Posted 2009) [#3]

It's probably just a matter of byte order. You need to match whatever flash-based sockets expect.

BlitzMax defaults to the endianness your CPU uses, LittleEndian for Intel and BigEndian for PowerPC. You can specify which one to use.

testfile$ = "data_12345678.bin"


TS:TStream = WriteStream( testfile ) 
WriteInt( TS, $12345678 )
CloseStream TS

TS = ReadStream( testfile )
DefaultEndian = ReadInt( TS )
CloseStream TS

TS = BigEndianStream( ReadStream( testfile ) )
BigEndian = ReadInt( TS )
CloseStream TS

TS = LittleEndianStream( ReadStream( testfile ) )
LittleEndian = ReadInt( TS )
CloseStream TS

DeleteFile testfile

Print
Print " Test endianness:"
Print
Print " Default " + Hex( DefaultEndian )
Print "  Little " + Hex( LittleEndian )
Print "     Big " + Hex( BigEndian )