/usr/share/perl5/Lintian/SlidingWindow.pm is in lintian 2.5.43.
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 | # -*- perl -*-
# Lintian::Data -- interface to match using a sliding window algorithm
# Copyright (C) 2013 Bastien ROUCARIÈS
#
# This program is free software; you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by the Free
# Software Foundation; either version 2 of the License, or (at your option)
# any later version.
#
# This program is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
# FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
# more details.
#
# You should have received a copy of the GNU General Public License along with
# this program. If not, see <http://www.gnu.org/licenses/>.
package Lintian::SlidingWindow;
use strict;
use warnings;
use autodie;
use Carp qw(croak);
use Lintian::Util qw(strip);
sub new {
my ($class, $handle, $blocksub, $blocksize) = @_;
$blocksize //= 4096;
my $self = {
'_handle' => $handle,
'_queue' => [q{}, q{}],
'_blocksize' => $blocksize,
'_blocksub' => $blocksub,
'_blocknumber' => -1,
};
return bless($self, $class);
}
sub readwindow {
my ($self) = @_;
my ($window, $queue);
my $first = $self->{'_blocknumber'} < 0;
{
# This path is too hot for autodie at its current performance
# (at the time of writing, that would be autodie/2.23).
# - Benchmark chromium-browser/32.0.1700.123-2/source
no autodie qw(read);
my $blocksize = $self->{'_blocksize'};
# Read twice the amount in the first window and split that
# into "two parts". That way we avoid half a block followed
# by a full block with the first half being identical to the
# previous one.
$blocksize *= 2 if $first;
my $res = read($self->{'_handle'}, $window, $blocksize);
if (not $res) {
die "read failed: $!\n" if not defined($res);
return;
}
}
if(defined($self->{'_blocksub'})) {
local $_ = $window;
$self->{'_blocksub'}->();
$window = $_;
}
$self->{'_blocknumber'}++;
$queue = $self->{'_queue'};
if ($first && $self->{'_blocksize'} < length($window)) {
# Split the first block into two windows. We assume here that
# if the two halves are not of equal length, then it is
# because the file is shorter than 2*blocksize. In this case,
# make the second half the shorter (it shouldn't matter and it
# is easier to do this way).
my $blocksize = $self->{'_blocksize'};
$queue->[0] = substr($window, 0, $blocksize);
$queue->[1] = substr($window, $blocksize);
return $window;
}
shift(@{$queue});
push(@{$queue}, $window);
return join('', @{$queue});
}
sub blocknumber {
my ($self) = @_;
if($self->{'_blocknumber'} == -1) {
return;
}
return $self->{'_blocknumber'};
}
=head1 NAME
Lintian::SlidingWindow - Lintian interface to sliding window match
=head1 SYNOPSIS
use Lintian::SlidingWindow;
my $sfd = Lintian::SlidingWindow->new('<','someevilfile.c', sub { $_ = lc($_); });
my $window;
while ($window = $sfd->readwindow()) {
if (index($window, 'evil') > -1) {
if($window =~
m/software \s++ shall \s++
be \s++ used \s++ for \s++ good \s*+ ,?+ \s*+
not \s++ evil/xsim) {
# do something like : tag 'license-problem-json-evil';
}
}
}
=head1 DESCRIPTION
Lintian::SlidingWindow provides a way of matching some pattern,
including multi line pattern, without needing to fully load the
file in memory.
=head1 CLASS METHODS
=over 4
=item new(HANDLE[, BLOCKSUB[, BLOCKSIZE]])
Create a new sliding window by reading from a given HANDLE, which must
be open for reading. Optionally run BLOCKSUB against each block. Note
that BLOCKSUB should apply transform byte by byte and does not depend
of context.
Each window consists of up to two blocks of BLOCKSIZE characters.
=back
=head1 INSTANCE METHODS
=over 4
=item readwindow
Return a new block of sliding window. Return undef at end of file.
=item blocknumber
return the number of block read by the instance. Return undef if no block has been read.
=back
=head1 DIAGNOSTICS
=over 4
=item no data type specified
=back
=head1 AUTHOR
Originally written by Bastien ROUCARIES for Lintian.
=head1 SEE ALSO
lintian(1)
=cut
1;
# Local Variables:
# indent-tabs-mode: nil
# cperl-indent-level: 4
# End:
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