#!/usr/bin/perl -w

my @output_buffer = ();
my $fname;

sub pure_guff($)
{
  my $array = shift;
  my @lines = @{$array};
  my $contains_sense = '';
  my $contains_guff = '';
  while (scalar @lines)
  {
    my $line = pop @lines;
    if ($line =~ m/\$Revision:/ ||
	$line =~ m/\$Author:/ ||
	$line =~ m/\$Date:/) {
      $contains_guff = '1';
    } elsif ($line =~ m/^[\+\-][^\-\+]/) {
      $contains_sense = '1';
    }
  }
  if ($contains_guff && $contains_sense) {
    print STDERR "Patch fragment with mixed good/bad changes in '$fname' near $line_index\n";
    $contains_guff = '';
  }
#  print "contains guff: $contains_guff\n";
  return $contains_guff;
}

sub output_lines($)
{
  my $array = shift;
  my @lines = @{$array};

  if (pure_guff (\@lines)) {
    return;
  }

  while (scalar @lines)
  {
    my $line = pop @lines;
    push @output_buffer, $line;
  }
}

my $header;
my @lines;
my $frag_count = 0;
$line_index = 0;

$fname = shift @ARGV;

open ($fhandle, $fname) || die "Can't open $fname: $!";
while (<$fhandle>) {
  if (/^\@\@/ || /^[^ \-\+]/) {
    output_lines (\@lines);
    @lines = ();
    $frag_count++;
  }
  unshift @lines, $_;
  $line_index++;
}
close($fhandle);
output_lines(\@lines);

if ($frag_count > 1) {
  print @output_buffer;
}
