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      1 #!/usr/bin/perl -w
      2 #
      3 # Copyright (C) 2008 Michael Brown <mbrown (at] fensystems.co.uk>.
      4 #
      5 # This program is free software; you can redistribute it and/or
      6 # modify it under the terms of the GNU General Public License as
      7 # published by the Free Software Foundation; either version 2 of the
      8 # License, or any later version.
      9 #
     10 # This program is distributed in the hope that it will be useful, but
     11 # WITHOUT ANY WARRANTY; without even the implied warranty of
     12 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     13 # General Public License for more details.
     14 #
     15 # You should have received a copy of the GNU General Public License
     16 # along with this program; if not, write to the Free Software
     17 # Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
     18 
     19 use strict;
     20 use warnings;
     21 use Getopt::Long;
     22 
     23 # List of licences we can handle
     24 my $known_licences = {
     25   gpl_any => {
     26     desc => "GPL (any version)",
     27     can_subsume => {
     28       public_domain => 1,
     29       bsd3 => 1,
     30       bsd2 => 1,
     31       mit  => 1,
     32       isc  => 1,
     33     },
     34   },
     35   gpl2_or_later => {
     36     desc => "GPL version 2 (or, at your option, any later version)",
     37     can_subsume => {
     38       gpl_any => 1,
     39       public_domain => 1,
     40       bsd3 => 1,
     41       bsd2 => 1,
     42       mit  => 1,
     43       isc  => 1,
     44     },
     45   },
     46   gpl2_only => {
     47     desc => "GPL version 2 only",
     48     can_subsume => {
     49       gpl_any => 1,
     50       gpl2_or_later => 1,
     51       public_domain => 1,
     52       bsd3 => 1,
     53       bsd2 => 1,
     54       mit  => 1,
     55       isc  => 1,
     56     },
     57   },
     58   public_domain => {
     59     desc => "Public Domain",
     60     can_subsume => {},
     61   },
     62   bsd4 => {
     63     desc => "BSD Licence (with advertising clause)",
     64     can_subsume => {
     65       public_domain => 1,
     66       bsd3 => 1,
     67       bsd2 => 1,
     68       mit  => 1,
     69       isc  => 1,
     70     },
     71   },
     72   bsd3 => {
     73     desc => "BSD Licence (without advertising clause)",
     74     can_subsume => {
     75       public_domain => 1,
     76       bsd2 => 1,
     77       mit  => 1,
     78       isc  => 1,
     79     },
     80   },
     81   bsd2 => {
     82     desc => "BSD Licence (without advertising or endorsement clauses)",
     83     can_subsume => {
     84       public_domain => 1,
     85       mit  => 1,
     86       isc  => 1,
     87     },
     88   },
     89   mit => {
     90     desc => "MIT/X11/Xorg Licence",
     91     can_subsume => {
     92       public_domain => 1,
     93       isc => 1,
     94     },
     95   },
     96   isc => {
     97     desc => "ISC Licence",
     98     can_subsume => {
     99       public_domain => 1,
    100     },
    101   },
    102 };
    103 
    104 # Parse command-line options
    105 my $verbosity = 1;
    106 Getopt::Long::Configure ( 'bundling', 'auto_abbrev' );
    107 GetOptions (
    108   'verbose|v+' => sub { $verbosity++; },
    109   'quiet|q+' => sub { $verbosity--; },
    110 ) or die "Could not parse command-line options\n";
    111 
    112 # Parse licence list from command line
    113 my $licences = {};
    114 foreach my $licence ( @ARGV ) {
    115   die "Unknown licence \"$licence\"\n"
    116       unless exists $known_licences->{$licence};
    117   $licences->{$licence} = $known_licences->{$licence};
    118 }
    119 die "No licences specified\n" unless %$licences;
    120 
    121 # Dump licence list
    122 if ( $verbosity >= 1 ) {
    123   print "The following licences appear within this file:\n";
    124   foreach my $licence ( keys %$licences ) {
    125     print "  ".$licences->{$licence}->{desc}."\n"
    126   }
    127 }
    128 
    129 # Apply licence compatibilities to reduce to a single resulting licence
    130 foreach my $licence ( keys %$licences ) {
    131   # Skip already-deleted licences
    132   next unless exists $licences->{$licence};
    133   # Subsume any subsumable licences
    134   foreach my $can_subsume ( keys %{$licences->{$licence}->{can_subsume}} ) {
    135     if ( exists $licences->{$can_subsume} ) {
    136       print $licences->{$licence}->{desc}." subsumes ".
    137 	  $licences->{$can_subsume}->{desc}."\n"
    138 	  if $verbosity >= 1;
    139       delete $licences->{$can_subsume};
    140     }
    141   }
    142 }
    143 
    144 # Print resulting licence
    145 die "Cannot reduce to a single resulting licence!\n"
    146     if ( keys %$licences ) != 1;
    147 ( my $licence ) = keys %$licences;
    148 print "The overall licence for this file is:\n  " if $verbosity >= 1;
    149 print $licences->{$licence}->{desc}."\n";
    150