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1 | package open; |
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2 | use Carp; |
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3 | $open::hint_bits = 0x20000; |
4 | |
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5 | our $VERSION = '1.01'; |
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6 | |
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7 | my $locale_encoding; |
8 | |
9 | sub in_locale { $^H & $locale::hint_bits } |
10 | |
11 | sub _get_locale_encoding { |
12 | unless (defined $locale_encoding) { |
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13 | eval { |
14 | # I18N::Langinfo isn't available everywhere |
15 | require I18N::Langinfo; |
16 | I18N::Langinfo->import('langinfo', 'CODESET'); |
17 | }; |
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18 | unless ($@) { |
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19 | $locale_encoding = langinfo(CODESET()); |
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20 | } |
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21 | my $country_language; |
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22 | if (not $locale_encoding && in_locale()) { |
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23 | if ($ENV{LC_ALL} =~ /^([^.]+)\.([^.]+)$/) { |
24 | ($country_language, $locale_encoding) = ($1, $2); |
25 | } elsif ($ENV{LANG} =~ /^([^.]+)\.([^.]+)$/) { |
26 | ($country_language, $locale_encoding) = ($1, $2); |
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27 | } |
28 | } else { |
29 | # Could do heuristics based on the country and language |
30 | # parts of LC_ALL and LANG (the parts before the dot (if any)), |
31 | # since we have Locale::Country and Locale::Language available. |
32 | # TODO: get a database of Language -> Encoding mappings |
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33 | # (the Estonian database at http://www.eki.ee/letter/ |
34 | # would be excellent!) --jhi |
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35 | } |
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36 | if (defined $locale_encoding && |
37 | $locale_encoding eq 'euc' && |
38 | defined $country_language) { |
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39 | if ($country_language =~ /^ja_JP|japan(?:ese)?$/i) { |
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40 | $locale_encoding = 'eucjp'; |
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41 | } elsif ($country_language =~ /^ko_KR|korean?$/i) { |
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42 | $locale_encoding = 'euckr'; |
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43 | } elsif ($country_language =~ /^zh_TW|taiwan(?:ese)?$/i) { |
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44 | $locale_encoding = 'euctw'; |
45 | } |
46 | croak "Locale encoding 'euc' too ambiguous" |
47 | if $locale_encoding eq 'euc'; |
48 | } |
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49 | } |
50 | } |
51 | |
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52 | sub import { |
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53 | my ($class,@args) = @_; |
54 | croak("`use open' needs explicit list of disciplines") unless @args; |
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55 | $^H |= $open::hint_bits; |
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56 | my ($in,$out) = split(/\0/,(${^OPEN} || "\0"), -1); |
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57 | while (@args) { |
58 | my $type = shift(@args); |
59 | my $discp = shift(@args); |
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60 | my @val; |
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61 | foreach my $layer (split(/\s+/,$discp)) { |
62 | $layer =~ s/^://; |
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63 | if ($layer eq 'locale') { |
64 | use Encode; |
65 | _get_locale_encoding() |
66 | unless defined $locale_encoding; |
67 | croak "Cannot figure out an encoding to use" |
68 | unless defined $locale_encoding; |
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69 | if ($locale_encoding =~ /^utf-?8$/i) { |
70 | $layer = "utf8"; |
71 | } else { |
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72 | $layer = "encoding($locale_encoding)"; |
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73 | } |
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74 | } else { |
75 | unless(PerlIO::Layer::->find($layer)) { |
76 | carp("Unknown discipline layer '$layer'"); |
77 | } |
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78 | } |
79 | push(@val,":$layer"); |
80 | if ($layer =~ /^(crlf|raw)$/) { |
81 | $^H{"open_$type"} = $layer; |
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82 | } |
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83 | } |
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84 | # print "# type = $type, val = @val\n"; |
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85 | if ($type eq 'IN') { |
86 | $in = join(' ',@val); |
87 | } |
88 | elsif ($type eq 'OUT') { |
89 | $out = join(' ',@val); |
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90 | } |
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91 | elsif ($type eq 'INOUT') { |
92 | $in = $out = join(' ',@val); |
93 | } |
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94 | else { |
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95 | croak "Unknown discipline class '$type'"; |
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96 | } |
97 | } |
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98 | ${^OPEN} = join('\0',$in,$out); |
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99 | } |
100 | |
101 | 1; |
102 | __END__ |
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103 | |
104 | =head1 NAME |
105 | |
106 | open - perl pragma to set default disciplines for input and output |
107 | |
108 | =head1 SYNOPSIS |
109 | |
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110 | use open IN => ":crlf", OUT => ":raw"; |
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111 | use open INOUT => ":utf8"; |
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112 | |
113 | =head1 DESCRIPTION |
114 | |
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115 | Full-fledged support for I/O disciplines is now implemented provided |
116 | Perl is configured to use PerlIO as its IO system (which is now the |
117 | default). |
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118 | |
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119 | The C<open> pragma serves as one of the interfaces to declare default |
120 | "layers" (aka disciplines) for all I/O. |
121 | |
122 | The C<open> pragma is used to declare one or more default layers for |
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123 | I/O operations. Any open(), readpipe() (aka qx//) and similar |
124 | operators found within the lexical scope of this pragma will use the |
125 | declared defaults. |
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126 | |
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127 | When open() is given an explicit list of layers they are appended to |
128 | the list declared using this pragma. |
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129 | |
130 | Directory handles may also support disciplines in future. |
131 | |
132 | =head1 NONPERLIO FUNCTIONALITY |
133 | |
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134 | If Perl is not built to use PerlIO as its IO system then only the two |
135 | pseudo-disciplines ":raw" and ":crlf" are available. |
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136 | |
137 | The ":raw" discipline corresponds to "binary mode" and the ":crlf" |
138 | discipline corresponds to "text mode" on platforms that distinguish |
139 | between the two modes when opening files (which is many DOS-like |
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140 | platforms, including Windows). These two disciplines are no-ops on |
141 | platforms where binmode() is a no-op, but perform their functions |
142 | everywhere if PerlIO is enabled. |
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143 | |
144 | =head1 IMPLEMENTATION DETAILS |
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145 | |
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146 | There is a class method in C<PerlIO::Layer> C<find> which is |
147 | implemented as XS code. It is called by C<import> to validate the |
148 | layers: |
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149 | |
150 | PerlIO::Layer::->find("perlio") |
151 | |
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152 | The return value (if defined) is a Perl object, of class |
153 | C<PerlIO::Layer> which is created by the C code in F<perlio.c>. As |
154 | yet there is nothing useful you can do with the object at the perl |
155 | level. |
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156 | |
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157 | =head1 SEE ALSO |
158 | |
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159 | L<perlfunc/"binmode">, L<perlfunc/"open">, L<perlunicode>, L<PerlIO> |
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160 | |
161 | =cut |