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
196
197
198
199
200
201
|
package Encode::CN::HZ;
use strict;
use warnings;
use utf8 ();
use vars qw($VERSION);
$VERSION = do { my @r = ( q$Revision: 2.10 $ =~ /\d+/g ); sprintf "%d." . "%02d" x $#r, @r };
use Encode qw(:fallbacks);
use parent qw(Encode::Encoding);
__PACKAGE__->Define('hz');
# HZ is a combination of ASCII and escaped GB, so we implement it
# with the GB2312(raw) encoding here. Cf. RFCs 1842 & 1843.
# not ported for EBCDIC. Which should be used, "~" or "\x7E"?
sub needs_lines { 1 }
sub decode ($$;$) {
my ( $obj, $str, $chk ) = @_;
return undef unless defined $str;
my $GB = Encode::find_encoding('gb2312-raw');
my $ret = substr($str, 0, 0); # to propagate taintedness
my $in_ascii = 1; # default mode is ASCII.
while ( length $str ) {
if ($in_ascii) { # ASCII mode
if ( $str =~ s/^([\x00-\x7D\x7F]+)// ) { # no '~' => ASCII
$ret .= $1;
# EBCDIC should need ascii2native, but not ported.
}
elsif ( $str =~ s/^\x7E\x7E// ) { # escaped tilde
$ret .= '~';
}
elsif ( $str =~ s/^\x7E\cJ// ) { # '\cJ' == LF in ASCII
1; # no-op
}
elsif ( $str =~ s/^\x7E\x7B// ) { # '~{'
$in_ascii = 0; # to GB
}
else { # encounters an invalid escape, \x80 or greater
last;
}
}
else { # GB mode; the byte ranges are as in RFC 1843.
no warnings 'uninitialized';
if ( $str =~ s/^((?:[\x21-\x77][\x21-\x7E])+)// ) {
my $prefix = $1;
$ret .= $GB->decode( $prefix, $chk );
}
elsif ( $str =~ s/^\x7E\x7D// ) { # '~}'
$in_ascii = 1;
}
else { # invalid
last;
}
}
}
$_[1] = '' if $chk; # needs_lines guarantees no partial character
return $ret;
}
sub cat_decode {
my ( $obj, undef, $src, $pos, $trm, $chk ) = @_;
my ( $rdst, $rsrc, $rpos ) = \@_[ 1 .. 3 ];
my $GB = Encode::find_encoding('gb2312-raw');
my $ret = '';
my $in_ascii = 1; # default mode is ASCII.
my $ini_pos = pos($$rsrc);
substr( $src, 0, $pos ) = '';
my $ini_len = bytes::length($src);
# $trm is the first of the pair '~~', then 2nd tilde is to be removed.
# XXX: Is better C<$src =~ s/^\x7E// or die if ...>?
$src =~ s/^\x7E// if $trm eq "\x7E";
while ( length $src ) {
my $now;
if ($in_ascii) { # ASCII mode
if ( $src =~ s/^([\x00-\x7D\x7F])// ) { # no '~' => ASCII
$now = $1;
}
elsif ( $src =~ s/^\x7E\x7E// ) { # escaped tilde
$now = '~';
}
elsif ( $src =~ s/^\x7E\cJ// ) { # '\cJ' == LF in ASCII
next;
}
elsif ( $src =~ s/^\x7E\x7B// ) { # '~{'
$in_ascii = 0; # to GB
next;
}
else { # encounters an invalid escape, \x80 or greater
last;
}
}
else { # GB mode; the byte ranges are as in RFC 1843.
if ( $src =~ s/^((?:[\x21-\x77][\x21-\x7F])+)// ) {
$now = $GB->decode( $1, $chk );
}
elsif ( $src =~ s/^\x7E\x7D// ) { # '~}'
$in_ascii = 1;
next;
}
else { # invalid
last;
}
}
next if !defined $now;
$ret .= $now;
if ( $now eq $trm ) {
$$rdst .= $ret;
$$rpos = $ini_pos + $pos + $ini_len - bytes::length($src);
pos($$rsrc) = $ini_pos;
return 1;
}
}
$$rdst .= $ret;
$$rpos = $ini_pos + $pos + $ini_len - bytes::length($src);
pos($$rsrc) = $ini_pos;
return ''; # terminator not found
}
sub encode($$;$) {
my ( $obj, $str, $chk ) = @_;
return undef unless defined $str;
my $GB = Encode::find_encoding('gb2312-raw');
my $ret = substr($str, 0, 0); # to propagate taintedness;
my $in_ascii = 1; # default mode is ASCII.
no warnings 'utf8'; # $str may be malformed UTF8 at the end of a chunk.
while ( length $str ) {
if ( $str =~ s/^([[:ascii:]]+)// ) {
my $tmp = $1;
$tmp =~ s/~/~~/g; # escapes tildes
if ( !$in_ascii ) {
$ret .= "\x7E\x7D"; # '~}'
$in_ascii = 1;
}
$ret .= pack 'a*', $tmp; # remove UTF8 flag.
}
elsif ( $str =~ s/(.)// ) {
my $s = $1;
my $tmp = $GB->encode( $s, $chk || 0 );
last if !defined $tmp;
if ( length $tmp == 2 ) { # maybe a valid GB char (XXX)
if ($in_ascii) {
$ret .= "\x7E\x7B"; # '~{'
$in_ascii = 0;
}
$ret .= $tmp;
}
elsif ( length $tmp ) { # maybe FALLBACK in ASCII (XXX)
if ( !$in_ascii ) {
$ret .= "\x7E\x7D"; # '~}'
$in_ascii = 1;
}
$ret .= $tmp;
}
}
else { # if $str is malformed UTF8 *and* if length $str != 0.
last;
}
}
$_[1] = $str if $chk;
# The state at the end of the chunk is discarded, even if in GB mode.
# That results in the combination of GB-OUT and GB-IN, i.e. "~}~{".
# Parhaps it is harmless, but further investigations may be required...
if ( !$in_ascii ) {
$ret .= "\x7E\x7D"; # '~}'
$in_ascii = 1;
}
utf8::encode($ret); # https://rt.cpan.org/Ticket/Display.html?id=35120
return $ret;
}
1;
__END__
=head1 NAME
Encode::CN::HZ -- internally used by Encode::CN
=cut
|