1package File::Compare;
2
3use 5.006;
4use strict;
5use warnings;
6our($VERSION, @ISA, @EXPORT, @EXPORT_OK, $Too_Big);
7
8require Exporter;
9use Carp;
10
11$VERSION = '1.1003';
12@ISA = qw(Exporter);
13@EXPORT = qw(compare);
14@EXPORT_OK = qw(cmp compare_text);
15
16$Too_Big = 1024 * 1024 * 2;
17
18sub compare {
19    croak("Usage: compare( file1, file2 [, buffersize]) ")
20      unless(@_ == 2 || @_ == 3);
21
22    my ($from,$to,$size) = @_;
23    my $text_mode = defined($size) && (ref($size) eq 'CODE' || $size < 0);
24
25    my ($fromsize,$closefrom,$closeto);
26    local (*FROM, *TO);
27
28    croak("from undefined") unless (defined $from);
29    croak("to undefined") unless (defined $to);
30
31    if (ref($from) &&
32        (UNIVERSAL::isa($from,'GLOB') || UNIVERSAL::isa($from,'IO::Handle'))) {
33	*FROM = *$from;
34    } elsif (ref(\$from) eq 'GLOB') {
35	*FROM = $from;
36    } else {
37	open(FROM,"<$from") or goto fail_open1;
38	unless ($text_mode) {
39	    binmode FROM;
40	    $fromsize = -s FROM;
41	}
42	$closefrom = 1;
43    }
44
45    if (ref($to) &&
46        (UNIVERSAL::isa($to,'GLOB') || UNIVERSAL::isa($to,'IO::Handle'))) {
47	*TO = *$to;
48    } elsif (ref(\$to) eq 'GLOB') {
49	*TO = $to;
50    } else {
51	open(TO,"<$to") or goto fail_open2;
52	binmode TO unless $text_mode;
53	$closeto = 1;
54    }
55
56    if (!$text_mode && $closefrom && $closeto) {
57	# If both are opened files we know they differ if their size differ
58	goto fail_inner if $fromsize != -s TO;
59    }
60
61    if ($text_mode) {
62	local $/ = "\n";
63	my ($fline,$tline);
64	while (defined($fline = <FROM>)) {
65	    goto fail_inner unless defined($tline = <TO>);
66	    if (ref $size) {
67		# $size contains ref to comparison function
68		goto fail_inner if &$size($fline, $tline);
69	    } else {
70		goto fail_inner if $fline ne $tline;
71	    }
72	}
73	goto fail_inner if defined($tline = <TO>);
74    }
75    else {
76	unless (defined($size) && $size > 0) {
77	    $size = $fromsize || -s TO || 0;
78	    $size = 1024 if $size < 512;
79	    $size = $Too_Big if $size > $Too_Big;
80	}
81
82	my ($fr,$tr,$fbuf,$tbuf);
83	$fbuf = $tbuf = '';
84	while(defined($fr = read(FROM,$fbuf,$size)) && $fr > 0) {
85	    unless (defined($tr = read(TO,$tbuf,$fr)) && $tbuf eq $fbuf) {
86		goto fail_inner;
87	    }
88	}
89	goto fail_inner if defined($tr = read(TO,$tbuf,$size)) && $tr > 0;
90    }
91
92    close(TO) || goto fail_open2 if $closeto;
93    close(FROM) || goto fail_open1 if $closefrom;
94
95    return 0;
96
97  # All of these contortions try to preserve error messages...
98  fail_inner:
99    close(TO) || goto fail_open2 if $closeto;
100    close(FROM) || goto fail_open1 if $closefrom;
101
102    return 1;
103
104  fail_open2:
105    if ($closefrom) {
106	my $status = $!;
107	$! = 0;
108	close FROM;
109	$! = $status unless $!;
110    }
111  fail_open1:
112    return -1;
113}
114
115sub cmp;
116*cmp = \&compare;
117
118sub compare_text {
119    my ($from,$to,$cmp) = @_;
120    croak("Usage: compare_text( file1, file2 [, cmp-function])")
121	unless @_ == 2 || @_ == 3;
122    croak("Third arg to compare_text() function must be a code reference")
123	if @_ == 3 && ref($cmp) ne 'CODE';
124
125    # Using a negative buffer size puts compare into text_mode too
126    $cmp = -1 unless defined $cmp;
127    compare($from, $to, $cmp);
128}
129
1301;
131
132__END__
133
134=head1 NAME
135
136File::Compare - Compare files or filehandles
137
138=head1 SYNOPSIS
139
140  	use File::Compare;
141
142	if (compare("file1","file2") == 0) {
143	    print "They're equal\n";
144	}
145
146=head1 DESCRIPTION
147
148The File::Compare::compare function compares the contents of two
149sources, each of which can be a file or a file handle.  It is exported
150from File::Compare by default.
151
152File::Compare::cmp is a synonym for File::Compare::compare.  It is
153exported from File::Compare only by request.
154
155File::Compare::compare_text does a line by line comparison of the two
156files. It stops as soon as a difference is detected. compare_text()
157accepts an optional third argument: This must be a CODE reference to
158a line comparison function, which returns 0 when both lines are considered
159equal. For example:
160
161    compare_text($file1, $file2)
162
163is basically equivalent to
164
165    compare_text($file1, $file2, sub {$_[0] ne $_[1]} )
166
167=head1 RETURN
168
169File::Compare::compare and its sibling functions return 0 if the files
170are equal, 1 if the files are unequal, or -1 if an error was encountered.
171
172=head1 AUTHOR
173
174File::Compare was written by Nick Ing-Simmons.
175Its original documentation was written by Chip Salzenberg.
176
177=cut
178
179