Lookfor and I/O Processing

Some communications programs have a different need - to collect (or discard) input until a specific pattern is detected. For lines, the pattern is a line-termination. But there are also requirements to search for other strings in the input such as "username:" and "password:". The lookfor method provides a consistant mechanism for solving this problem. It searches input character-by-character looking for a match to any of the elements of an array set using the are_match method. It returns the entire input up to the match pattern if a match is found. If no match is found, it returns "" unless an input error or abort is detected (which returns undef).

thank you everybody! this is how I got the name/value pares into variables

#!/usr/bin/perl
use warnings;
use strict;

use Device::SerialPort;

my $ccnt;
my $port = '/dev/ttyUSB0';
my $conf = '~/.conf-pasha';
my $ob = Device::SerialPort->new($port, 1) || die "Can't open $port: $
+!";

my $STALL_DEFAULT = 10;
my $timeout = $STALL_DEFAULT;

my $arb  = $ob->can_arbitrary_baud;
my $data = $ob->databits(8);
my $baud = $ob->baudrate(19200);
my $parity = $ob->parity("none");
my $hshake = $ob->handshake("rts");
my $stop = $ob->can_stopbits;
my $rs = $ob->is_rs232;
my $total = $ob->can_total_timeout;

$ob->stopbits(1);
$ob->buffers( 4096, 4096 );
$ob->can_baud;
$ob->can_databits;
$ob->can_dtrdsr;
$ob->can_handshake;
$ob->can_parity_check;
$ob->can_parity_config;
$ob->can_parity_enable;
$ob->can_rtscts;
$ob->can_xonxoff;
$ob->can_xon_char;
$ob->can_spec_char;
$ob->can_interval_timeout;
$ob->can_ioctl;
$ob->can_status;
$ob->can_write_done;
$ob->can_modemlines;
$ob->can_wait_modemlines;
$ob->can_intr_count;
$ob->write_settings;

my ($count, $string, $name, $value);
my @vals;

while(1) {
        $ccnt++;
        $ob->lastline("\n");

        ($count, $string) = $ob->read(255);

        print "$ccnt\n\n";
        @vals  = split("\n", $string);
        foreach (@vals) {
                $_=~ s/\t/\=/;
                $_=~ s/\r//;
                $_=~ s/\n//;
                ($name, $value) = split("=", $_);
                next unless ($name);
                $value = 0 unless ($value);
                $value = $value/1000 if $name =~ /I/g;
                print "$name=$value\n";
        }
        sleep(1);
}




$ob->write_drain;
$ob->close;
undef $ob
[download]

Many, many moons ago (early 90s)I had reason to collect data from a PBX system that was sent out over an RS232 connection. I found that I had to read a line at a time instead of a fixed block in order to get reasonable data chunks to work with. It looks like you have a similar situation to that.

I haven't had a chance to grok Device::SerialPort yet, but I would suspect it has some kind of input function that is similar to readln that would be suitable.

Assuming that is the case, then it should be relatively simple to bring in a line at a time for parsing/storing and then processing the collected data whenever the closing "Checksum" entry is detected. Doing a split /\s+/ might come in handy for that. (I tend to be partial to dispatch tables for working with record types.)