#!/usr/bin/perl -w
#
# comstrip.pl - strips all comments from Verilog RTL
# There is control over synopsys directives,
# and you can remove blank lines.
# 
# By Jeff Winston  http://www.kwcpa.com/tools  tools@kwcpa.com
#
# For usage help: Type comstrip.pl with no parameters
#
# Rev. 1.0,    8/16/09 Copyright (C) 2009
# Rev. 1.1,   10/31/09 Copyright (C) 2009  added support for synopsys comments
#
# ---------------------------------------------------------------------
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
# 
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
# 
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
# USA.  or check out http://www.gnu.org/copyleft/gpl.html
# ---------------------------------------------------------------------
#

# print help
if ($#ARGV < 1) {print_help();}

# parse input line
$noblank=0;
$nosynopsys=0;
while ($#ARGV > 1) {
    if ($ARGV[0] eq "-n") {
	$noblank=1;
	shift @ARGV;
    } elsif ($ARGV[0] eq "-s") {
	$nosynopsys=1;
	shift @ARGV;
    }
}

$infile  = shift @ARGV;
$outfile = shift @ARGV;


# open files
open (INFIL,"< $infile")  or die "Failed to open $infile";
open (OUT  ,"> $outfile") or die "Failed to open $outfile";

# clear global flags
$in_comment=0;
$re_process=0;

# process input file
while (1) {
   # if no lines to re-process, and no new lines, we're done
    if (($re_process == 0) && (!(defined($line=<INFIL>)))) {
	last;
    }
    # need to chomp if new line, 
    if ($re_process == 0) {chomp $line};

    $last_reprocess = $re_process;
    $re_process=0; # clear re-processing flag, store old value

    if ($in_comment == 1) {
	# if we're inside a comment and find */, get remainder of line and process
	if ($line =~ /\*\//) {
	    $in_comment=0; # no longer in comment
	    $cend = index($line,"*/");
	    $line = substr($line,$cend+2);
	    $re_process=1; 
	}
	else {
	    # otherwise, if we're inside a comment, do nothing, except if we're re-processing, 
	    # terminate line.
	    if ($last_reprocess == 2) {print OUT "\n";}
	    next;
	}
    }
    else { # not currently inside comment
	# pick first comment, if any...
	$c0start = index($line,"/*");
	$c1start = index($line,"//");

	if ($nosynopsys == 0) {
	    # allow synopsys comments
	    $linetmp = substr($line,$c0start);
	    $linetmp =~ s/\s+/\ /g;
	    if (($linetmp =~ /^\/\* synopsys /) || 
		($linetmp =~ /^\/\* synopsys /)) {
		$c0start = -1;
	    }
	    $linetmp = substr($line,$c1start);
	    $linetmp =~ s/\s+/\ /g;
	    if (($linetmp =~ /^\/\/ synopsys /) || 
		($linetmp =~ /^\/\/ synopsys /)) {
		$c1start = -1;
	    }
	}

	# no comment, output line
	if (($c0start == -1) && ($c1start == -1)) {
	    if (not_all_white($line)) {
		print OUT $line . "\n";
	    }
	}
	# otherwise, if single-line comment, comes first, output line up to start of comment
	elsif (($c0start == -1) || (($c1start > -1) && ($c1start < $c0start))) {
	    $subline = substr($line,0,$c1start);
	    if (not_all_white($subline)) {
		print OUT $subline. "\n";
	    }
        # otherwise, start of /* comment. output the line up to start of comment
        # and re-process line after comment start (if any), but set in-comment flag
	} elsif ($c0start != -1) {
	    $subline = substr($line,0,$c0start);
	    $line = substr($line,$c0start+2);
	    $in_comment=1;
	    if (not_all_white($subline)) {
		print OUT $subline;
		$re_process=2; # 2 means line not terminated
	    } else {
		$re_process=1;
	    }
	}
    }
}
# finish up
close (INFIL);
close (OUT);
print "$outfile written\n";
exit;

# if enabled, flag strings that are 0 length or all whitespace
sub not_all_white {
    if ($noblank == 0) {return(1);}
    $str = shift @_;

    if ((length($str) == 0) || ($str =~ /^\s+$/)) {return(0);}
    return(1);
}

sub print_help {
    print "\nUsage: comstrip.pl [-n] [-s] <input_file> <output_file>\n";
    print " -n means also remove all blank lines\n\n";
    print " -s means also remove all synopsys directives\n\n";
    exit;
}