wcal

#!/usr/bin/perl
use POSIX;

my ($month, $year) = @ARGV;
if (@ARGV < 1)
{
   my ($sec,$min,$hour,$mday,$mon,$yr) = localtime();
   $month = $mon+1;
   $year = $yr + 1900;
}

if (($month < 1) || (12 < $month))
{
   print("  usage: wcal <month> [<year>]n");
   exit;
}

if (! defined($year))
{
   $year = this_year();
}

%DATA = ("left.HANDLE" => "LEFT",
         "left.VAR" => $left,
         "left.SUB" => &last_month,

         "mid.HANDLE" => "MID",
         "mid.VAR" => $mid,
         "mid.SUB" => &this_month,

         "right.HANDLE" => "RIGHT",
         "right.VAR" => $right,
         "right.SUB" => &next_month);

foreach $key (qw/left mid right/)
{
   ${$DATA{"$key.VAR"}} = &{$DATA{"$key.SUB"}}($month, $year);
   my $cmd = sprintf("cal %s", ${$DATA{"$key.VAR"}});
   open($DATA{"$key.HANDLE"}, "$cmd |");
}

# foreach $fhandle (qw/LEFT MID RIGHT/)
# {
#    open($fhandle, "cal $left|");
# }
# open(MID, "cal $mid|");
# open(RIGHT, "cal $right|");

for ($done = 0 ; !$done ; )
{
   $done = 1;
	foreach $key (qw/left mid right/)
	{
      my $handle = $DATA{"$key.HANDLE"};
      chomp(${$DATA{"$key.VAR"}} = <$handle>);
      if (defined(${$DATA{"$key.VAR"}})) 
      { 
         $done = 0;
         if ($^O eq "aix")
         {
            if (${$DATA{"$key.VAR"}} =~ /^    /)
            {
               ${$DATA{"$key.VAR"}} =~ s/    /   /g;
               ${$DATA{"$key.VAR"}} =~ s/(d)  / /g;
            }
            else
            {
               ${$DATA{"$key.VAR"}} =~ s/  / /g;
            }
         }
         ${$DATA{"$key.VAR"}} =~ s/([A-Z][a-z])[a-z] / /g;
      }
	}

   if (!$done)
   {
      print("  ");
      foreach $key (qw/left mid right/)
      {
         printf("%-25s ", ${$DATA{"$key.VAR"}});
      }
   }
   print("n");
}

# ===========================================================================
sub myr
{
   my ($umon, $uyear) = @_;
   my $now = mktime(0, 0, 0, 1, $umon-1, $uyear-1900);
   return $now;
}

# ===========================================================================
sub last_month
{
   my $now = myr(@_);
   my ($sec,$min,$hour,$mday,$mon,$year) = localtime($now);
   ($sec,$min,$hour,$mday,$mon,$year) = localtime($now - ($mday*24*3600));
   my $rval = sprintf("%d %d", 1+$mon, 1900+$year);
   return $rval;
}

# ===========================================================================
sub this_month
{
   my $now = myr(@_);
   my ($sec,$min,$hour,$mday,$mon,$year) = localtime($now);
   my $rval = sprintf("%d %d", 1+$mon, 1900+$year);
   return $rval;
}

# ===========================================================================
sub this_year
{
   my ($sec,$min,$hour,$mday,$mon,$year) = localtime();
   return 1900+$year;
}

# ===========================================================================
sub next_month
{
   my $now = myr(@_);
   my ($sec,$min,$hour,$mday,$mon,$year) = localtime($now);
   my ($sec,$min,$hour,$mday,$mon,$year) 
      = localtime($now + ((35-$mday)*24*3600));
   my $rval = sprintf("%d %d", 1+$mon, 1900+$year);
   return $rval;
}