#! /usr/bin/env perl

use File::Basename;

sub usage()
{
  print "Usage:\n";
  print "  $0 [ <filename > | <filename> <rev> | \n" .
        "       M +<digits> -<digits> <filename <rev> ]\n";
  print "\n";
  
  exit 5;
}

my $filename;

my $argc = scalar @ARGV;

if ($argc > 0 and $argc < 3 ) {
  $filename = $ARGV[0];
  $cvsversion= dirname($0) . "/cvsversion";
  $version=`$cvsversion $filename`;
  chomp $version;
  $version=$ARGV[1] if ($argc > 1 and $ARGV[1] =~ /^[\d\.]{3,}$/);
} elsif ($argc == 5) {
  $filename=$ARGV[3] if (-f $ARGV[3]);
  $version=$ARGV[4] if ($ARGV[4] =~ /^[\d\.]{3,}$/);
} else {
  &usage();
}

die "$0: filename expected" if(!length($filename));
die "$filename: $!\n" if (! -f $filename);

my $vold = $version;
my $vnew = $version;

if ($version=~/^.*\.1$/) {
  $vold = $1 if ($version=~/^(\d+\.\d+(?:\.\d+\.\d+)*)\.\d+\.1$/);
}
else {
  if ($version=~/^(.*)\.([^.]*)$/) { $v1 = $1; $v2 = $2 } 
  $v2old = ${v2}-1;
  $vold = $v1 . '.' . $v2old;
}
my $base = basename($filename);
my $dir = dirname($filename);
my $cmd = "cd $dir; cvs -f log -N -r$vnew $base";
print "$cmd\n";
system("$cmd");
my $whitespace = "";
$whitespace = "-b" unless (defined $ENV{"CVSLASTCHANGE_KEEP_WHITESPACE"});
$cmd = "cd $dir; cvs -f diff -kk $whitespace -p -u -r$vold -r$vnew $base";
print "$cmd\n";
system("$cmd");