http://www.perlmonks.org?node_id=1005964
jagexCoder has asked for the wisdom of the Perl Monks concerning the following question:

Hi there! Iam working on some serial networking relating code and need to 'find' packets of interest that are within STX and ETX endings. Basically we have a device that sends data of the format: "STX|PAYLOAD|CRC|ETX" (without the | symbol) to another device that I am writing a simulator script for. Basically I want the receive routine to only start copying a valid data packet into the buffer once it sees an STX and stops reading once it sees an ETX or if 80 bytes has already been received and no ETX was found. I am using "Win32::SerialPort". Here's what I have so far:
sub writeSerialPort { my $WRITE_TO_PORT = shift; $port->write($WRITE_TO_PORT) || die("Writing to the serial port fa +iled: $!\n"); # STDOUT -> flush; sleep 2 } sub readSerialPort { sleep 3; $byte=$port->input; $buffer .= $byte; #print "\nBuffer: " . $buffer; #print "\n"; #print "\nByte: " . $byte; $byte = ""; # This variable is emptied each time new data comes i +n and is added to the buffer }
I thought of using Regular expressions to detect the STX and ETX components something along the lines of, if as an example, buffer contained 'cool': print $buffer =~ /(\0x63\0x6F\0x6F\0x6C)/; This does not return true. I'm somewhat new to perl so can someone please shed some light on this and give me guidance on how I can get the checking I described at the start working? Thanks!