| Current Path : /proc/2/root/usr/local/share/perl5/Net/DNS/ |
| Current File : //proc/2/root/usr/local/share/perl5/Net/DNS/Text.pm |
package Net::DNS::Text;
#
# $Id: Text.pm 1726 2018-12-15 12:59:56Z willem $
#
our $VERSION = (qw$LastChangedRevision: 1726 $)[1];
=head1 NAME
Net::DNS::Text - DNS text representation
=head1 SYNOPSIS
use Net::DNS::Text;
$object = new Net::DNS::Text('example');
$string = $object->string;
$object = decode Net::DNS::Text( \$data, $offset );
( $object, $next ) = decode Net::DNS::Text( \$data, $offset );
$data = $object->encode;
$text = $object->value;
=head1 DESCRIPTION
The C<Net::DNS::Text> module implements a class of text objects
with associated class and instance methods.
Each text object instance has a fixed identity throughout its
lifetime.
=cut
use strict;
use warnings;
use integer;
use Carp;
use constant ASCII => ref eval {
require Encode;
Encode::find_encoding('ascii');
};
use constant UTF8 => scalar eval { ## not UTF-EBCDIC [see Unicode TR#16 3.6]
Encode::encode_utf8( chr(182) ) eq pack( 'H*', 'C2B6' );
};
=head1 METHODS
=head2 new
$object = new Net::DNS::Text('example');
Creates a text object which encapsulates a single character
string component of a resource record.
Arbitrary single-byte characters can be represented by \ followed
by exactly three decimal digits. Such characters are devoid of
any special meaning.
A character preceded by \ represents itself, without any special
interpretation.
=cut
my ( %escape, %unescape ); ## precalculated ASCII escape tables
sub new {
my $self = bless [], shift;
croak 'argument undefined' unless defined $_[0];
local $_ = &_encode_utf8;
s/^\042(.*)\042$/$1/s; # strip paired quotes
s/\134\134/\134\060\071\062/g; # disguise escaped escape
s/\134([\060-\071]{3})/$unescape{$1}/eg; # numeric escape
s/\134(.)/$1/g; # character escape
while ( length $_ > 255 ) {
my $chunk = substr( $_, 0, 255 ); # carve into chunks
substr( $chunk, -length($1) ) = '' if $chunk =~ /.([\300-\377][\200-\277]*)$/;
push @$self, $chunk;
substr( $_, 0, length $chunk ) = '';
}
push @$self, $_;
return $self;
}
=head2 decode
$object = decode Net::DNS::Text( \$buffer, $offset );
( $object, $next ) = decode Net::DNS::Text( \$buffer, $offset );
Creates a text object which represents the decoded data at the
indicated offset within the data buffer.
The argument list consists of a reference to a scalar containing
the wire-format data and offset of the text data.
The returned offset value indicates the start of the next item in
the data buffer.
=cut
sub decode {
my $class = shift;
my $buffer = shift; # reference to data buffer
my $offset = shift || 0; # offset within buffer
my $size = shift; # specify size of unbounded text
unless ( defined $size ) {
$size = unpack "\@$offset C", $$buffer;
$offset++;
}
my $next = $offset + $size;
croak 'corrupt wire-format data' if $next > length $$buffer;
my $self = bless [unpack( "\@$offset a$size", $$buffer )], $class;
return wantarray ? ( $self, $next ) : $self;
}
=head2 encode
$data = $object->encode;
Returns the wire-format encoded representation of the text object
suitable for inclusion in a DNS packet buffer.
=cut
sub encode {
my $self = shift;
join '', map pack( 'C a*', length $_, $_ ), @$self;
}
=head2 raw
$data = $object->raw;
Returns the wire-format encoded representation of the text object
without the explicit length field.
=cut
sub raw {
my $self = shift;
join '', map pack( 'a*', $_ ), @$self;
}
=head2 value
$value = $text->value;
Character string representation of the text object.
=cut
sub value {
return unless defined wantarray;
my $self = shift;
_decode_utf8( join '', @$self );
}
=head2 string
$string = $text->string;
Conditionally quoted zone file representation of the text object.
=cut
sub string {
my $self = shift;
my @s = map split( '', $_ ), @$self; # escape special and ASCII non-printable
my $string = _decode_utf8( join '', map $escape{$_}, @s );
return $string unless $string =~ /[ \t\n\r\f]|^$|;$/; # unquoted contiguous
$string =~ s/\\([^"0-9])/$1/g; # unescape printable characters except \"
join '', '"', $string, '"'; # quoted string
}
########################################
# perlcc: address of encoding objects must be determined at runtime
my $ascii = ASCII ? Encode::find_encoding('ascii') : undef; # Osborn's Law:
my $utf8 = UTF8 ? Encode::find_encoding('utf8') : undef; # Variables won't; constants aren't.
sub _decode_utf8 { ## UTF-8 to perl internal encoding
local $_ = shift;
# partial transliteration for non-ASCII character encodings
tr
[\040-\176\000-\377]
[ !"#$%&'()*+,\-./0-9:;<=>?@A-Z\[\\\]^_`a-z{|}~?] unless ASCII;
my $z = length($_) - length($_); # pre-5.18 taint workaround
ASCII ? substr( ( UTF8 ? $utf8 : $ascii )->decode($_), $z ) : $_;
}
sub _encode_utf8 { ## perl internal encoding to UTF-8
local $_ = shift;
# partial transliteration for non-ASCII character encodings
tr
[ !"#$%&'()*+,\-./0-9:;<=>?@A-Z\[\\\]^_`a-z{|}~]
[\040-\176] unless ASCII;
my $z = length($_) - length($_); # pre-5.18 taint workaround
ASCII ? substr( ( UTF8 ? $utf8 : $ascii )->encode($_), $z ) : $_;
}
%escape = eval { ## precalculated ASCII/UTF-8 escape table
my @C0 = ( 0 .. 31 ); # control characters
my @NA = UTF8 ? ( 192, 193, 216 .. 223, 245 .. 255 ) : ( 128 .. 255 );
my %table = ( # transparent, \" \( \) \; \\
map( ( $_ => $_ ), map pack( 'C', $_ ), ( 0 .. 255 ) ),
map( ( pack( 'C', $_ ) => pack( 'C2', 92, $_ ) ), ( 34, 40, 41, 59, 92 ) ),
);
foreach my $n ( @C0, 92, 127, @NA ) { # numerical escape
my $codepoint = sprintf( '%03u', $n );
# transliteration for non-ASCII character encodings
$codepoint =~ tr [0-9] [\060-\071];
$table{pack( 'C', $n )} = pack 'C a3', 92, $codepoint;
}
return %table;
};
%unescape = eval { ## precalculated numeric escape table
my %table;
foreach my $n ( 0 .. 255 ) {
my $key = sprintf( '%03u', $n );
# transliteration for non-ASCII character encodings
$key =~ tr [0-9] [\060-\071];
$table{$key} = pack 'C', $n;
}
$table{"\060\071\062"} = pack 'C2', 92, 92; # escaped escape
return %table;
};
1;
__END__
########################################
=head1 BUGS
Coding strategy is intended to avoid creating unnecessary argument
lists and stack frames. This improves efficiency at the expense of
code readability.
Platform specific character coding features are conditionally
compiled into the code.
=head1 COPYRIGHT
Copyright (c)2009-2011 Dick Franks.
All rights reserved.
=head1 LICENSE
Permission to use, copy, modify, and distribute this software and its
documentation for any purpose and without fee is hereby granted, provided
that the above copyright notice appear in all copies and that both that
copyright notice and this permission notice appear in supporting
documentation, and that the name of the author not be used in advertising
or publicity pertaining to distribution of the software without specific
prior written permission.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
DEALINGS IN THE SOFTWARE.
=head1 SEE ALSO
L<perl>, L<Net::DNS>, RFC1035, RFC3629, Unicode TR#16
=cut
Copyright 2K16 - 2K18 Indonesian Hacker Rulez
;?>)