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86530b38 AT |
1 | package Encode::MIME::Header; |
2 | use strict; | |
3 | # use warnings; | |
4 | our $VERSION = do { my @r = (q$Revision: 1.5 $ =~ /\d+/g); sprintf "%d."."%02d" x $#r, @r }; | |
5 | ||
6 | use Encode qw(find_encoding encode_utf8); | |
7 | use MIME::Base64; | |
8 | use Carp; | |
9 | ||
10 | my %seed = | |
11 | ( | |
12 | decode_b => '1', # decodes 'B' encoding ? | |
13 | decode_q => '1', # decodes 'Q' encoding ? | |
14 | encode => 'B', # encode with 'B' or 'Q' ? | |
15 | bpl => 75, # bytes per line | |
16 | ); | |
17 | ||
18 | $Encode::Encoding{'MIME-Header'} = | |
19 | bless { | |
20 | %seed, | |
21 | Name => 'MIME-Header', | |
22 | } => __PACKAGE__; | |
23 | ||
24 | $Encode::Encoding{'MIME-B'} = | |
25 | bless { | |
26 | %seed, | |
27 | decode_q => 0, | |
28 | Name => 'MIME-B', | |
29 | } => __PACKAGE__; | |
30 | ||
31 | $Encode::Encoding{'MIME-Q'} = | |
32 | bless { | |
33 | %seed, | |
34 | decode_q => 1, | |
35 | encode => 'Q', | |
36 | Name => 'MIME-Q', | |
37 | } => __PACKAGE__; | |
38 | ||
39 | use base qw(Encode::Encoding); | |
40 | ||
41 | sub needs_lines { 1 } | |
42 | sub perlio_ok{ 0 }; | |
43 | ||
44 | sub decode($$;$){ | |
45 | use utf8; | |
46 | my ($obj, $str, $chk) = @_; | |
47 | # zap spaces between encoded words | |
48 | $str =~ s/\?=\s+=\?/\?==\?/gos; | |
49 | # multi-line header to single line | |
50 | $str =~ s/(:?\r|\n|\r\n)[ \t]//gos; | |
51 | $str =~ | |
52 | s{ | |
53 | =\? # begin encoded word | |
54 | ([0-9A-Za-z\-_]+) # charset (encoding) | |
55 | \?([QqBb])\? # delimiter | |
56 | (.*?) # Base64-encodede contents | |
57 | \?= # end encoded word | |
58 | }{ | |
59 | if (uc($2) eq 'B'){ | |
60 | $obj->{decode_b} or croak qq(MIME "B" unsupported); | |
61 | decode_b($1, $3); | |
62 | }elsif(uc($2) eq 'Q'){ | |
63 | $obj->{decode_q} or croak qq(MIME "Q" unsupported); | |
64 | decode_q($1, $3); | |
65 | }else{ | |
66 | croak qq(MIME "$2" encoding is nonexistent!); | |
67 | } | |
68 | }egox; | |
69 | $_[1] = '' if $chk; | |
70 | return $str; | |
71 | } | |
72 | ||
73 | sub decode_b{ | |
74 | my $enc = shift; | |
75 | my $d = find_encoding($enc) or croak(Unknown encoding "$enc"); | |
76 | my $db64 = decode_base64(shift); | |
77 | return $d->decode($db64, Encode::FB_PERLQQ); | |
78 | } | |
79 | ||
80 | sub decode_q{ | |
81 | my ($enc, $q) = @_; | |
82 | my $d = find_encoding($enc) or croak(Unknown encoding "$enc"); | |
83 | $q =~ s/_/ /go; | |
84 | $q =~ s/=([0-9A-Fa-f]{2})/pack("C", hex($1))/ego; | |
85 | return $d->decode($q, Encode::FB_PERLQQ); | |
86 | } | |
87 | ||
88 | my $especials = | |
89 | join('|' => | |
90 | map {quotemeta(chr($_))} | |
91 | unpack("C*", qq{()<>@,;:\"\'/[]?.=})); | |
92 | ||
93 | my $re_especials = qr/$especials/o; | |
94 | ||
95 | sub encode($$;$){ | |
96 | my ($obj, $str, $chk) = @_; | |
97 | my @line = (); | |
98 | for my $line (split /\r|\n|\r\n/o, $str){ | |
99 | my (@word, @subline); | |
100 | for my $word (split /($re_especials)/o, $line){ | |
101 | if ($word =~ /[^\x00-\x7f]/o){ | |
102 | push @word, $obj->_encode($word); | |
103 | }else{ | |
104 | push @word, $word; | |
105 | } | |
106 | } | |
107 | my $subline = ''; | |
108 | for my $word (@word){ | |
109 | use bytes (); | |
110 | if (bytes::length($subline) + bytes::length($word) > $obj->{bpl}){ | |
111 | push @subline, $subline; | |
112 | $subline = ''; | |
113 | } | |
114 | $subline .= $word; | |
115 | } | |
116 | $subline and push @subline, $subline; | |
117 | push @line, join("\n " => @subline); | |
118 | } | |
119 | $_[1] = '' if $chk; | |
120 | return join("\n", @line); | |
121 | } | |
122 | ||
123 | use constant HEAD => '=?UTF-8?'; | |
124 | use constant TAIL => '?='; | |
125 | use constant SINGLE => { B => \&_encode_b, Q => \&_encode_q, }; | |
126 | ||
127 | sub _encode{ | |
128 | my ($o, $str) = @_; | |
129 | my $enc = $o->{encode}; | |
130 | my $llen = ($o->{bpl} - length(HEAD) - 2 - length(TAIL)); | |
131 | # to coerce a floating-point arithmetics, the following contains | |
132 | # .0 in numbers -- dankogai | |
133 | $llen *= $enc eq 'B' ? 3.0/4.0 : 1.0/3.0; | |
134 | my @result = (); | |
135 | my $chunk = ''; | |
136 | while(my $chr = substr($str, 0, 1, '')){ | |
137 | use bytes (); | |
138 | if (bytes::length($chunk) + bytes::length($chr) > $llen){ | |
139 | push @result, SINGLE->{$enc}($chunk); | |
140 | $chunk = ''; | |
141 | } | |
142 | $chunk .= $chr; | |
143 | } | |
144 | $chunk and push @result, SINGLE->{$enc}($chunk); | |
145 | return @result; | |
146 | } | |
147 | ||
148 | sub _encode_b{ | |
149 | HEAD . 'B?' . encode_base64(encode_utf8(shift), '') . TAIL; | |
150 | } | |
151 | ||
152 | sub _encode_q{ | |
153 | my $chunk = shift; | |
154 | $chunk =~ s{ | |
155 | ([^0-9A-Za-z]) | |
156 | }{ | |
157 | join("" => map {sprintf "=%02X", $_} unpack("C*", $1)) | |
158 | }egox; | |
159 | return HEAD . 'Q?' . $chunk . TAIL; | |
160 | } | |
161 | ||
162 | 1; | |
163 | __END__ | |
164 | ||
165 | =head1 NAME | |
166 | ||
167 | Encode::MIME::Header -- MIME 'B' and 'Q' header encoding | |
168 | ||
169 | =head1 SYNOPSIS | |
170 | ||
171 | use Encode qw/encode decode/; | |
172 | $utf8 = decode('MIME-Header', $header); | |
173 | $header = encode('MIME-Header', $utf8); | |
174 | ||
175 | =head1 ABSTRACT | |
176 | ||
177 | This module implements RFC 2047 Mime Header Encoding. There are 3 | |
178 | variant encoding names; C<MIME-Header>, C<MIME-B> and C<MIME-Q>. The | |
179 | difference is described below | |
180 | ||
181 | decode() encode() | |
182 | ---------------------------------------------- | |
183 | MIME-Header Both B and Q =?UTF-8?B?....?= | |
184 | MIME-B B only; Q croaks =?UTF-8?B?....?= | |
185 | MIME-Q Q only; B croaks =?UTF-8?Q?....?= | |
186 | ||
187 | =head1 DESCRIPTION | |
188 | ||
189 | When you decode(=?I<encoding>?I<X>?I<ENCODED WORD>?=), I<ENCODED WORD> | |
190 | is extracted and decoded for I<X> encoding (B for Base64, Q for | |
191 | Quoted-Printable). Then the decoded chunk is fed to | |
192 | decode(I<encoding>). So long as I<encoding> is supported by Encode, | |
193 | any source encoding is fine. | |
194 | ||
195 | When you encode, it just encodes UTF-8 string with I<X> encoding then | |
196 | quoted with =?UTF-8?I<X>?....?= . The parts that RFC 2047 forbids to | |
197 | encode are left as is and long lines are folded within 76 bytes per | |
198 | line. | |
199 | ||
200 | =head1 BUGS | |
201 | ||
202 | It would be nice to support encoding to non-UTF8, such as =?ISO-2022-JP? | |
203 | and =?ISO-8859-1?= but that makes the implementation too complicated. | |
204 | These days major mail agents all support =?UTF-8? so I think it is | |
205 | just good enough. | |
206 | ||
207 | =head1 SEE ALSO | |
208 | ||
209 | L<Encode> | |
210 | ||
211 | RFC 2047, L<http://www.faqs.org/rfcs/rfc2047.html> and many other | |
212 | locations. | |
213 | ||
214 | =cut |