How to handle raw byte data naturally

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Question

alex chang · Sep 3, 2020

#ObjectScript #Caché

I have java language experence. If I need parse a binary tcp packet . like following format

encoded string and send it to peer by tcp

1byte msg type + 4 byte(unsigned int) + raw byte(body)

To parse this package , Some Java code like this:

byte[] data = new byte[1024];

Bytebuf buf = new ByteBuf(data)

byte type = buf.read()

int len = buf.ReadInt()

byte[] bodyBuff = new byte[len]

buf.Read(bodyBuff)

String str = new String(strBody)

So, does Objectscript have similar functionality to achieve similar results?

Tks.

Discussion (1)0

Robert Cemper · Sep 3, 2020

let's have your binary input in variable data

JAVA ObjectScript
byte[] data = new byte[1024];   ;
Bytebuf buf = new ByteBuf(data) set buf=data ; make your work copy
byte type = buf.read() set type=$extract(buf) ; if type = character
  set type=$ascii(buf) ; if type = binary
int len = buf.ReadInt() set len=$zlascii($extract(buf,2,5)) ; if order low->high    set len=$zlascii($reverse($extract(buf,2,5))) ; li order high->low
byte[] bodyBuff = new byte[len] ;
buf.Read(bodyBuff)   ;
String str = new String(strBody)   set str=$extract(buf,6,*) ; take rest of buf

from the description there are 2 open points:

is type a binary value or a character
for length it could be
- low byte first so 515 => x/02 03 00 00 ; default
- or high byte first so 515 => x/00 00 02 03 ; need to reverse order

therefore I have added both variants

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