lib/Automake/Version.pm

   1 # Copyright (C) 2001, 2002, 2003, 2010 Free Software Foundation, Inc.
   2
   3 # This program is free software; you can redistribute it and/or modify
   4 # it under the terms of the GNU General Public License as published by
   5 # the Free Software Foundation; either version 2, or (at your option)
   6 # any later version.
   7
   8 # This program is distributed in the hope that it will be useful,
   9 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  10 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11 # GNU General Public License for more details.
  12
  13 # You should have received a copy of the GNU General Public License
  14 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  15
  16 package Automake::Version;
  17 use strict;
  18 use Automake::ChannelDefs;
  19
  20 =head1 NAME
  21
  22 Automake::Version - version comparison
  23
  24 =head1 SYNOPSIS
  25
  26   use Automake::Version;
  27
  28   print "Version $version is older than required version $required\n"
  29     if Automake::Version::check ($version, $required);
  30
  31 =head1 DESCRIPTION
  32
  33 This module provides support for comparing versions string
  34 as they are used in Automake.
  35
  36 A version is a string that looks like
  37 C<MAJOR.MINOR[.MICRO][ALPHA][-FORK]> where C<MAJOR>, C<MINOR>, and
  38 C<MICRO> are digits, C<ALPHA> is a character, and C<FORK> any
  39 alphanumeric word.
  40
  41 Usually, C<ALPHA> is used to label alpha releases or intermediate
  42 snapshots, C<FORK> is used for git branches or patched releases, and
  43 C<MICRO> is used for bug fixes releases on the C<MAJOR.MINOR> branch.
  44
  45 For the purpose of ordering, C<1.4> is the same as C<1.4.0>, but
  46 C<1.4g> is the same as C<1.4.99g>.  The C<FORK> identifier is ignored
  47 in the ordering, except when it looks like C<-pMINOR[ALPHA]>: some
  48 versions were labeled like C<1.4-p3a>, this is the same as an alpha
  49 release labeled C<1.4.3a>.  Yes, it's horrible, but Automake did not
  50 support two-dot versions in the past.
  51
  52 =head2 FUNCTIONS
  53
  54 =over 4
  55
  56 =item C<split ($version)>
  57
  58 Split the string C<$version> into the corresponding C<(MAJOR, MINOR,
  59 MICRO, ALPHA, FORK)> tuple.  For instance C<'1.4g'> would be split
  60 into C<(1, 4, 99, 'g', '')>.  Return C<()> on error.
  61
  62 =cut
  63
  64 sub split ($)
  65 {
  66   my ($ver) = @_;
  67
  68   # Special case for versions like 1.4-p2a.
  69   if ($ver =~ /^(\d+)\.(\d+)(?:-p(\d+)([a-z]+)?)$/)
  70   {
  71     return ($1, $2, $3, $4 || '', '');
  72   }
  73   # Common case.
  74   elsif ($ver =~ /^(\d+)\.(\d+)(?:\.(\d+))?([a-z])?(?:-([A-Za-z0-9]+))?$/)
  75   {
  76     return ($1, $2, $3 || (defined $4 ? 99 : 0), $4 || '', $5 || '');
  77   }
  78   return ();
  79 }
  80
  81 =item C<compare (\@LVERSION, \@RVERSION)>
  82
  83 Compare two version tuples, as returned by C<split>.
  84
  85 Return 1, 0, or -1, if C<LVERSION> is found to be respectively
  86 greater than, equal to, or less than C<RVERSION>.
  87
  88 =cut
  89
  90 sub compare (\@\@)
  91 {
  92   my @l = @{$_[0]};
  93   my @r = @{$_[1]};
  94
  95   for my $i (0, 1, 2)
  96   {
  97     return 1  if ($l[$i] > $r[$i]);
  98     return -1 if ($l[$i] < $r[$i]);
  99   }
 100   for my $i (3, 4)
 101   {
 102     return 1  if ($l[$i] gt $r[$i]);
 103     return -1 if ($l[$i] lt $r[$i]);
 104   }
 105   return 0;
 106 }
 107
 108 =item C<check($VERSION, $REQUIRED)>
 109
 110 Handles the logic of requiring a version number in Automake.
 111 C<$VERSION> should be Automake's version, while C<$REQUIRED>
 112 is the version required by the user input.
 113
 114 Return 0 if the required version is satisfied, 1 otherwise.
 115
 116 =cut
 117
 118 sub check ($$)
 119 {
 120   my ($version, $required) = @_;
 121   my @version = Automake::Version::split ($version);
 122   my @required = Automake::Version::split ($required);
 123
 124   prog_error "version is incorrect: $version"
 125     if $#version == -1;
 126
 127   # This should not happen, because process_option_list and split_version
 128   # use similar regexes.
 129   prog_error "required version is incorrect: $required"
 130     if $#required == -1;
 131
 132   # If we require 3.4n-foo then we require something
 133   # >= 3.4n, with the `foo' fork identifier.
 134   return 1
 135     if ($required[4] ne '' && $required[4] ne $version[4]);
 136
 137   return 0 > compare (@version, @required);
 138 }
 139
 140 1;
 141
 142 ### Setup "GNU" style for perl-mode and cperl-mode.
 143 ## Local Variables:
 144 ## perl-indent-level: 2
 145 ## perl-continued-statement-offset: 2
 146 ## perl-continued-brace-offset: 0
 147 ## perl-brace-offset: 0
 148 ## perl-brace-imaginary-offset: 0
 149 ## perl-label-offset: -2
 150 ## cperl-indent-level: 2
 151 ## cperl-brace-offset: 0
 152 ## cperl-continued-brace-offset: 0
 153 ## cperl-label-offset: -2
 154 ## cperl-extra-newline-before-brace: t
 155 ## cperl-merge-trailing-else: nil
 156 ## cperl-continued-statement-offset: 2
 157 ## End: