Locale::Recode(3pm)

1Locale::Recode(3)     User Contributed Perl Documentation    Locale::Recode(3)
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NAME

6       Locale::Recode - Object-Oriented Portable Charset Conversion
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SYNOPSIS

9         use Locale::Recode;
10
11         $cd = Locale::Recode->new (from => 'UTF-8',
12                                    to   => 'ISO-8859-1');
13
14         die $cd->getError if $cd->getError;
15
16         $cd->recode ($text) or die $cd->getError;
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18         $mime_name = Locale::Recode->resolveAlias ('latin-1');
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20         $supported = Locale::Recode->getSupported;
21
22         $complete = Locale::Recode->getCharsets;
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DESCRIPTION

25       This module provides routines that convert textual data from one code‐
26       set to another in a portable way.  The module has been started before
27       Encode(3) was written.  It's main purpose today is to provide charset
28       conversion even when Encode(3) is not available on the system.  It
29       should also work for older Perl versions without Unicode support.
30
31       Internally Locale::Recode(3) will use Encode(3) whenever possible, to
32       allow for a faster conversion and for a wider range of supported
33       charsets, and will only fall back to the Perl implementation when
34       Encode(3) is not available or does not support a particular charset
35       that Locale::Recode(3) does.
36
37       Locale::Recode(3) is part of libintl-perl, and it's main purpose is
38       actually to implement a portable charset conversion framework for the
39       message translation facilities described in Locale::TextDomain(3).
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CONSTRUCTOR

42       The constructor "new()" requires two named arguments:
43
44       from
45           The encoding of the original data.  Case doesn't matter, aliases
46           are resolved.
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48       to  The target encoding.  Again, case doesn't matter, and aliases are
49           resolved.
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51       The constructor will never fail.  In case of an error, the object's
52       internal state is set to bad and it will refuse to do any conversions.
53       You can inquire the reason for the failure with the method getError().
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OBJECT METHODS

56       The following object methods are available.
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58       recode (STRING)
59           Converts STRING from the source encoding into the destination
60           encoding.  In case of success, a truth value is returned, false
61           otherwise.  You can inquire the reason for the failure with the
62           method getError().
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64       getError
65           Returns either false if the object is not in an error state or an
66           error message.
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CLASS METHODS

69       The object provides some additional class methods:
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71       getSupported
72           Returns a reference to a list of all supported charsets.  This may
73           implicitely load additional Encode(3) conversions like
74           Encode::HanExtra(3) which may produce considerable load on your
75           system.
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77           The method is therefore not intended for regular use but rather for
78           getting resp. displaying once a list of available encodings.
79
80           The members of the list are all converted to uppercase!
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82       getCharsets
83           Like getSupported() but also returns all available aliases.
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SUPPORTED CHARSETS

86       The range of supported charsets is system-dependent.  The following
87       somewhat special charsets are always available:
88
89       UTF-8
90           UTF-8 is available independently of your Perl version.  For Perl
91           5.6 or better or in the presence of Encode(3), conversions are not
92           done in Perl but with the interfaces provided by these facilities
93           which are written in C, hence much faster.
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95           Encoding data into UTF-8 is fast, even if it is done in Perl.
96           Decoding it in Perl may become quite slow.  If you frequently have
97           to decode UTF-8 with Locale::Recode you will probably want to make
98           sure that you do that with Perl 5.6 or beter, or install Encode(3)
99           to speed up things.
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101       INTERNAL
102           UTF-8 is fast to write but hard to read for applications.  It is
103           therefore not the worst for internal string representation but not
104           far from that.  Locale::Recode(3) stores strings internally as a
105           reference to an array of integer values like most programming lan‐
106           guages (Perl is an exception) do, trading memory for performance.
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108           The integer values are the UCS-4 codes of the characters in host
109           byte order.
110
111           The encoding INTERNAL is directly availabe via Locale::Recode(3)
112           but of course you should not really use it for data exchange,
113           unless you know what you are doing.
114
115       Locale::Recode(3) has native support for a plethora of other encodings,
116       most of them 8 bit encodings that are fast to decode, including most
117       encodings used on popular micros like the ISO-8859-* series of encod‐
118       ings, most Windows-* encodings (also known as CP*), Macintosh, Atari,
119       etc.
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NAMES AND ALIASES

122       Each charset resp. encoding is available internally under a unique
123       name.  Whenever the information was available, the preferred MIME name
124       (see <http://www.iana.org/assignments/character-sets/>) was chosen as
125       the internal name.
126
127       Alias handling is quite strict.  The module does not make wild guesses
128       at what you mean ("What's the meaning of the acronym JIS" is a valid
129       alias for "7bit-jis" in Encode(3) ....) but aims at providing common
130       aliases only.  The same applies to so-called aliases that are really
131       mistakes, like "utf8" for UTF-8.
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133       The module knows all aliases that are listed with the IANA character
134       set registry (<http://www.iana.org/assignments/character-sets/>), plus
135       those known to libiconv version 1.8, and a bunch of additional ones.
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CONVERSION TABLES

138       The conversion tables have either been taken from official sources like
139       the IANA or the Unicode Consortium, from Bruno Haible's libiconv, or
140       from the sources of the GNU libc and the regression tests for libintl-
141       perl will check for conformance here.  For some encodings this data
142       differs from Encode(3)'s data which would cause these tests to fail.
143       In these cases, the module will not invoke the Encode(3) methods, but
144       will fall back to the internal implementation for the sake of consis‐
145       tency.
146
147       The few encodings that are affected are so simple that you will not
148       experience any real performance penalty unless you convert large chunks
149       of data.  But the package is not really intended for such use anyway,
150       and since Encode(3) is relatively new, I rather think that the differ‐
151       ences are bugs in Encode which will be fixed soon.
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BUGS

154       The module should provide fall back conversions for other Unicode
155       encoding schemes like UCS-2, UCS-4 (big- and little-endian).
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157       The pure Perl UTF-8 decoder will not always handle corrupt UTF-8 cor‐
158       rectly, especially at the end and at the beginning of the string.  This
159       is not likely to be fixed, since the module's intention is not to be a
160       consistency checker for UTF-8 data.
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AUTHOR

163       Copyright (C) 2002-2004, Guido Flohr <guido@imperia.net>, all rights
164       reserved.  See the source code for details.
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166       This software is contributed to the Perl community by Imperia
167       (<http://www.imperia.net/>).
168