SCX/Reader.pm

   1 #!/usr/bin/perl -w
   2
   3 package SCX::Reader;
   4
   5 use Time::HiRes qw(gettimeofday tv_interval);
   6 use FileHandle;
   7 use SCX::CRC;
   8
   9 our $PACKET_SIZE = 10;
  10 our $LOG_ROTATE  = 600;
  11
  12 sub new {
  13         my ($class, $args) = @_;
  14
  15         my $callback = $args->{callback}
  16                 or die "callback arg not defined";
  17
  18         my $portname = $args->{portname}
  19                 or die "portname not specified";
  20
  21         system 'stty', '-F', $portname, '115200', 'raw';
  22         if ($?) {
  23                 die "stty died with code $? (no permissions?)";
  24         }
  25
  26         open my $tty, '<:raw', $portname
  27                 or die "Can't open $portname: $!";
  28
  29         my $logfile = $args->{logfile};
  30         my $log_gen = 0;
  31
  32         open my $logfh, '>', "$logfile.$log_gen"
  33         or die "Can't open $logfile.$log_gen: $!";
  34
  35         my $now = gettimeofday;
  36
  37         my $self = {
  38                 portname  => $portname,
  39                 fh        => $tty,
  40                 logfile   => $logfile,
  41                 logfh     => $logfh,
  42                 log_gen   => $log_gen,
  43                 log_start => $now,
  44                 starttime => $now,
  45                 callback  => $callback,
  46                 bytes     => [],
  47         };
  48
  49         bless $self, $class;
  50
  51         return $self;
  52 }
  53
  54 sub fh { return shift->{fh}; }
  55
  56 sub read {
  57         my ($self) = @_;
  58
  59         my $data;
  60         my $bytes_read = sysread $self->fh, $data, $PACKET_SIZE;
  61         die "Read error on $self->{portname}: $!"
  62                 if !$bytes_read;
  63
  64         my $now = gettimeofday;
  65         if ($now - $self->{log_start} >= $LOG_ROTATE) {
  66                 close $self->{logfh};
  67                 $self->{log_gen} = $self->{log_gen} ? 0 : 1;
  68                 open my $fh, '>', $logfile . '.' . $self->{log_gen}
  69                         or die "Can't open $logfile.$self->{log_gen}: $!";
  70                 $self->{logfh} = $fh;
  71                 $self->{log_start} = $now;
  72         }
  73
  74         my @bytes = unpack("C*", $data);
  75
  76         $self->{logfh}->print(sprintf('% 10.3f', $now - $self->{starttime}),
  77                 (map { sprintf(" %02x", $_) } @bytes),
  78                 "\n");
  79
  80         push @{ $self->{bytes} }, @bytes;
  81         @bytes = @{ $self->{bytes} };
  82
  83         my @bad_bytes;
  84
  85         while (@bytes >= $PACKET_SIZE) {
  86                 if ($bytes[0] != 0x55 || $bytes[9] != 0x05
  87                         || SCX::CRC::digest(@bytes[0..7]) != $bytes[8]) {
  88                         push @bad_bytes, shift @bytes;
  89                         next;
  90                 }
  91
  92                 if (@bad_bytes) {
  93                         $self->{logfh}->print("Cannot parse bytes",
  94                                 (map { sprintf(' %02x', $_) } @bad_bytes),
  95                                 "\n");
  96                         @bad_bytes = ();
  97                 }
  98
  99                 $self->{logfh}->print("Callback\n");
 100                 &{ $self->{callback} }(@bytes[1..7]);
 101                 splice @bytes, 0, 10;
 102         }
 103         if (@bad_bytes) {
 104                 $self->{logfh}->print("Cannot parse bytes",
 105                         (map { sprintf(' %02x', $_) } @bad_bytes),
 106                         "\n");
 107                 @bad_bytes = ();
 108         }
 109
 110         @{ $self->{bytes} } = @bytes;
 111 }
 112
 113 1;
 114