/usr/share/perl5/Convert/Ascii85.pm is in libconvert-ascii85-perl 0.01-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 | package Convert::Ascii85;
use warnings;
use strict;
our $VERSION = '0.01';
use Exporter qw(import);
our @EXPORT_OK = qw(ascii85_encode ascii85_decode);
my $_space_no = unpack 'N', ' ' x 4;
sub encode {
my ($in, $opt) = @_;
my $compress_zero = exists $opt->{compress_zero} ? $opt->{compress_zero} : 1;
my $compress_space = $opt->{compress_space};
my $padding = -length($in) % 4;
$in .= "\0" x $padding;
my $out = '';
for my $n (unpack 'N*', $in) {
if ($n == 0 && $compress_zero) {
$out .= 'z';
next;
}
if ($n == $_space_no && $compress_space) {
$out .= 'y';
next;
}
my $tmp = '';
for my $i (reverse 0 .. 4) {
my $mod = $n % 85;
$n = int($n / 85);
vec($tmp, $i, 8) = $mod + 33;
}
$out .= $tmp;
}
$padding or return $out;
$out =~ s/z\z/!!!!!/;
substr $out, 0, length($out) - $padding
}
*ascii85_encode = \&encode;
sub decode {
my ($in) = @_;
for ($in) {
tr[ \t\r\n\f][]d;
s/z/!!!!!/g;
s/y/+<VdL/g;
}
my $padding = -length($in) % 5;
$in .= 'u' x $padding;
my $out = '';
for my $n (unpack '(a5)*', $in) {
my $tmp = 0;
for my $i (unpack 'C*', $n) {
$tmp *= 85;
$tmp += $i - 33;
}
$out .= pack 'N', $tmp;
}
substr $out, 0, length($out) - $padding
}
*ascii85_decode = \&decode;
1
__END__
=head1 NAME
Convert::Ascii85 - Encoding and decoding of ascii85/base85 strings
=head1 SYNOPSIS
use Convert::Ascii85;
my $encoded = Convert::Ascii85::encode($data);
my $decoded = Convert::Ascii85::decode($encoded);
use Convert::Ascii85 qw(ascii85_encode ascii85_decode);
my $encoded = ascii85_encode($data);
my $decoded = ascii85_decode($encoded);
=head1 DESCRIPTION
This module implements the I<Ascii85> (also known as I<Base85>) algorithm for
encoding binary data as text. This is done by interpreting each group of four
bytes as a 32-bit integer, which is then converted to a five-digit base-85
representation using the digits from ASCII 33 (C<!>) to 117 (C<u>).
This is similar to L<MIME::Base64> but more space efficient: The overhead is
only 1/4 of the original data (as opposed to 1/3 for Base64).
=head1 FUNCTIONS
=over 4
=item Convert::Ascii85::encode DATA
=item Convert::Ascii85::encode DATA, OPTIONS
Converts the bytes in DATA to Ascii85 and returns the resulting text string.
OPTIONS is a hash reference in which the following keys may be set:
=over
=item compress_zero => 0
By default, four-byte chunks of null bytes (C<"\0\0\0\0">) are converted to
C<'z'> instead of C<'!!!!!'>. This can be avoided by passing a false value for
C<compress_zero> in OPTIONS.
=item compress_space => 1
By default, four-byte chunks of spaces (C<' '>) are converted to C<'+<VdL'>.
If you pass a true value for C<compress_space> in OPTIONS, they will be
converted to C<'y'> instead.
=back
This function may be exported as C<ascii85_encode> into the caller's namespace.
=item Convert::Ascii85::decode TEXT
Converts the Ascii85-encoded TEXT back to bytes and returns the resulting byte
string. Spaces and linebreaks in TEXT are ignored.
This function may be exported as C<ascii85_decode> into the caller's namespace.
=back
=head1 SEE ALSO
L<http://en.wikipedia.org/wiki/Ascii85>,
L<MIME::Base64>
=head1 AUTHOR
Lukas Mai, C<< <l.mai at web.de> >>
=head1 BUGS
Please report any bugs or feature requests to C<bug-convert-ascii85 at rt.cpan.org>, or through
the web interface at L<http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Convert-Ascii85>. I will be notified, and then you'll
automatically be notified of progress on your bug as I make changes.
=head1 SUPPORT
You can find documentation for this module with the perldoc command.
perldoc Convert::Ascii85
You can also look for information at:
=over 4
=item * RT: CPAN's request tracker
L<http://rt.cpan.org/NoAuth/Bugs.html?Dist=Convert-Ascii85>
=item * AnnoCPAN: Annotated CPAN documentation
L<http://annocpan.org/dist/Convert-Ascii85>
=item * CPAN Ratings
L<http://cpanratings.perl.org/d/Convert-Ascii85>
=item * Search CPAN
L<http://search.cpan.org/dist/Convert-Ascii85/>
=back
=head1 LICENSE AND COPYRIGHT
Copyright 2011 Lukas Mai.
This program is free software; you can redistribute it and/or modify it
under the terms of either: the GNU General Public License as published
by the Free Software Foundation; or the Artistic License.
See http://dev.perl.org/licenses/ for more information.
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