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87 lines
1.7 KiB
Perl
Executable file
87 lines
1.7 KiB
Perl
Executable file
package Digest::Crc32;
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# Cyclic Redundency Check interface for buffers and files
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use strict;
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use Carp;
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use vars qw($VERSION $poly);
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$VERSION = 0.01;
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$poly = 0xEDB88320;
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sub version { sprintf("%f", $VERSION); }
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sub new {
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my $self = {};
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my $proto = shift;
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my $class = ref($proto) || $proto;
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bless($self,$class);
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return $self;
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}
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sub _crc32 {
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my $self = shift;
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my $comp = shift;
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for (my $cnt = 0; $cnt < 8; $cnt++) { $comp = $comp & 1 ? $poly ^ ($comp >> 1) : $comp >> 1; }
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return $comp;
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}
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sub strcrc32 {
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my $self = shift;
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my $crc = 0xFFFFFFFF;
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my ($tcmp) = @_;
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foreach (split(//,$tcmp)) { $crc = (($crc>>8) & 0x00FFFFFF) ^ $self->_crc32(($crc ^ ord($_)) & 0xFF); }
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return $crc^0xFFFFFFFF;
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}
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sub filecrc32 {
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my $self = shift;
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my $file = shift;
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my $crc = 0xFFFFFFFF;
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open(FILE, $file) or croak "Failed to open the file";
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while (<FILE>) {
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foreach (split(//,$_)) { $crc = (($crc>>8) & 0x00FFFFFF) ^ $self->_crc32(($crc ^ ord($_)) & 0xFF); }
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}
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close(FILE);
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return $crc^0xFFFFFFFF;
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}
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=head1 NAME
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Digest::CRC32 - Cyclic Redundency Check digests implementation
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=head1 VERSION
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0.01
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=head1 SYNOPSIS
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use Digest::CRC32;
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my $crc = new Digest::CRC32();
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# Digest for a string
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printf $crc->strcrc32("Hello world");
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#Digest for a file
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print $crc->filecrc32($myfile);
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=head1 DESCRIPTION
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This module provides a perl implementation to generate 32 bits CRC digests for buffers and files.
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=head1 COPYRIGHT
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Copyright 2004 by Faycal Chraibi. All rights reserved.
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This library is a free software. You can redistribute it and/or modify it under the same terms as Perl itself.
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=head1 AUTHOR
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Faycal Chraibi <fays@cpan.org>
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=head1 SEE ALSO
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L<Digest::CRC>
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