#!/usr/local/bin/perl
#
# This script gets the current temperatures from all specified probes
# on a "Hot Little Therm" and writes out to a log file.
#
# By: Theo Van Dinter <tvd@chrysalis.com>
#
# Log format:
#  time{:probe temp}
#
# time is the number of seconds since epoch (time()), following is any
# number of ":probeID temp" sections (as many probes as you have).
#

use strict;

my($hlt) = 1; # number of probes to check
my($device) = "ttyS0"; # which device (under /dev)?
my($logfile) = "/home/tvd/hlt/hlt.log";

# -- Do not edit below this line -- #

my(@temps) = ();

MAIN: {
  my($rin,$win,$ein,$num,$text);

  open(T,"+</dev/$device") || die "can't open /dev/$device:$!";
  select((select(T),$|=1)[0]); # non-buffered to device
  
  # get ready to do a select (polling -- boo!)
  $rin = $win = $ein = "";
  vec($rin, fileno(T), 1) = 1;
  $ein = $rin;
  
  for($num=0;$num < $hlt;$num++){ # run through all probes
    printf T "%c",16+$num; # probe on device $num
    
    do { # read in info from probe
      my($t)=select($rin,undef,$ein,3); # wait for data to be readable
      last if ( $t == -1 ); # end on error.
      next unless ( $t ); # skip if no data is readable
      
      sysread T, $text, 10, length($text); # add to end of text line.
    } until ( $text=~/Z\s*$/ ); # go until end of input.
  }
  close(T);
  @temps = ( $text =~ /\bT(\w{16} [+-]\d+\.\d+)\b/g );
}

LOGGING: {
  my($line) = "";

  foreach ( @temps ) {
    tr/+-//d; # get rid of the +/- business
    $line = join(":",$line,$_);
  }
  open(OUT,">>$logfile") || die "Can't append $logfile:$!";
  print OUT time,"$line\n";
  close(OUT);
}