Only copy headers if they've changed.

#!/usr/local/bin/perl

use strict;

use Fcntl;

# copy-if-different.pl

# Copy to the destination if the source is not the same as it.

my $stripcr = 0;

my @filelist;

foreach my $arg (@ARGV) {

	$arg =~ s|\\|/|g;	# compensate for bug/feature in cygwin glob...

	foreach (glob $arg)

		{

		push @filelist, $_;

		}

}

my $fnum = @filelist;

if ($fnum <= 1)

	{

	die "Need at least two filenames";

	}

my $dest = pop @filelist;

if ($fnum > 2 && ! -d $dest)

	{

	die "Destination must be a directory";

	}

foreach (@filelist)

	{

        my $dfile;

	if (-d $dest)

		{

		$dfile = $_;

		$dfile =~ s|^.*[/\\]([^/\\]*)$|$1|;

		$dfile = "$dest/$dfile";

		}

	else

		{

		$dfile = $dest;

		}

	my $buf;

	if (-f $dfile)

		{

		sysopen(IN, $_, O_RDONLY|O_BINARY) || die "Can't Open $_";

		sysopen(OUT, $dfile, O_RDONLY|O_BINARY)

		  || die "Can't Open $dfile";

		while (sysread IN, $buf, 10240)

			{

			my $b2;

			goto copy if !sysread(OUT, $b2, 10240) || $buf ne $b2;

			}

		goto copy if sysread(OUT, $buf, 1);

		close(IN);

		close(OUT);

		print "NOT copying: $_ to $dfile\n";

		next;

		}

      copy:

	sysopen(IN, $_, O_RDONLY|O_BINARY) || die "Can't Open $_";

	sysopen(OUT, $dfile, O_WRONLY|O_CREAT|O_TRUNC|O_BINARY)

					|| die "Can't Open $dfile";

	while (sysread IN, $buf, 10240)

		{

		syswrite(OUT, $buf, length($buf));

		}

	close(IN);

	close(OUT);

	print "Copying: $_ to $dfile\n";

	}

		if ($n =~ /bss_file/)

			{ $pp=".c"; }

		else	{ $pp=$p; }

		$ret.="$to${o}$n$pp: \$(SRC_D)$o$_$pp $to\n\t\$(CP) \"\$(SRC_D)$o$_$pp\" \"$to${o}$n$pp\"\n\n";

		$ret.="$to${o}$n$pp: \$(SRC_D)$o$_$pp $to\n\t\$(SRC_D)${o}util${o}copy-if-different.pl \"\$(SRC_D)$o$_$pp\" \"$to${o}$n$pp\"\n\n";

		}

	return($ret);

	}