Compare.pm revision 1.1 
1package File::Compare;
2
3use strict;
4use vars qw($VERSION @ISA @EXPORT @EXPORT_OK $Too_Big *FROM *TO);
5
6require Exporter;
7use Carp;
8
9$VERSION = '1.1001';
10@ISA = qw(Exporter);
11@EXPORT = qw(compare);
12@EXPORT_OK = qw(cmp);
13
14$Too_Big = 1024 * 1024 * 2;
15
16sub VERSION {
17    # Version of File::Compare
18    return $File::Compare::VERSION;
19}
20
21sub compare {
22    croak("Usage: compare( file1, file2 [, buffersize]) ")
23      unless(@_ == 2 || @_ == 3);
24
25    my $from = shift;
26    my $to = shift;
27    my $closefrom=0;
28    my $closeto=0;
29    my ($size, $fromsize, $status, $fr, $tr, $fbuf, $tbuf);
30    local(*FROM, *TO);
31    local($\) = '';
32
33    croak("from undefined") unless (defined $from);
34    croak("to undefined") unless (defined $to);
35
36    if (ref($from) &&
37        (UNIVERSAL::isa($from,'GLOB') || UNIVERSAL::isa($from,'IO::Handle'))) {
38	*FROM = *$from;
39    } elsif (ref(\$from) eq 'GLOB') {
40	*FROM = $from;
41    } else {
42	open(FROM,"<$from") or goto fail_open1;
43	binmode FROM;
44	$closefrom = 1;
45	$fromsize = -s FROM;
46    }
47
48    if (ref($to) &&
49        (UNIVERSAL::isa($to,'GLOB') || UNIVERSAL::isa($to,'IO::Handle'))) {
50	*TO = *$to;
51    } elsif (ref(\$to) eq 'GLOB') {
52	*TO = $to;
53    } else {
54	open(TO,"<$to") or goto fail_open2;
55	binmode TO;
56	$closeto = 1;
57    }
58
59    if ($closefrom && $closeto) {
60	# If both are opened files we know they differ if their size differ
61	goto fail_inner if $fromsize != -s TO;
62    }
63
64    if (@_) {
65	$size = shift(@_) + 0;
66	croak("Bad buffer size for compare: $size\n") unless ($size > 0);
67    } else {
68	$size = $fromsize;
69	$size = 1024 if ($size < 512);
70	$size = $Too_Big if ($size > $Too_Big);
71    }
72
73    $fbuf = '';
74    $tbuf = '';
75    while(defined($fr = read(FROM,$fbuf,$size)) && $fr > 0) {
76	unless (defined($tr = read(TO,$tbuf,$fr)) and $tbuf eq $fbuf) {
77            goto fail_inner;
78	}
79    }
80    goto fail_inner if (defined($tr = read(TO,$tbuf,$size)) && $tr > 0);
81
82    close(TO) || goto fail_open2 if $closeto;
83    close(FROM) || goto fail_open1 if $closefrom;
84
85    return 0;
86
87  # All of these contortions try to preserve error messages...
88  fail_inner:
89    close(TO) || goto fail_open2 if $closeto;
90    close(FROM) || goto fail_open1 if $closefrom;
91
92    return 1;
93
94  fail_open2:
95    if ($closefrom) {
96	$status = $!;
97	$! = 0;
98	close FROM;
99	$! = $status unless $!;
100    }
101  fail_open1:
102    return -1;
103}
104
105*cmp = \&compare;
106
1071;
108
109__END__
110
111=head1 NAME
112
113File::Compare - Compare files or filehandles
114
115=head1 SYNOPSIS
116
117  	use File::Compare;
118
119	if (compare("file1","file2") == 0) {
120	    print "They're equal\n";
121	}
122
123=head1 DESCRIPTION
124
125The File::Compare::compare function compares the contents of two
126sources, each of which can be a file or a file handle.  It is exported
127from File::Compare by default.
128
129File::Compare::cmp is a synonym for File::Compare::compare.  It is
130exported from File::Compare only by request.
131
132=head1 RETURN
133
134File::Compare::compare return 0 if the files are equal, 1 if the
135files are unequal, or -1 if an error was encountered.
136
137=head1 AUTHOR
138
139File::Compare was written by Nick Ing-Simmons.
140Its original documentation was written by Chip Salzenberg.
141
142=cut
143
144