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48 KiB
HTML
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>Facets</title><meta name="generator" content="DocBook XSL Stylesheets Vsnapshot" /><meta name="keywords" content="ISO C++, library" /><meta name="keywords" content="ISO C++, runtime, library" /><link rel="home" href="../index.html" title="The GNU C++ Library" /><link rel="up" href="localization.html" title="Chapter 8. Localization" /><link rel="prev" href="localization.html" title="Chapter 8. Localization" /><link rel="next" href="containers.html" title="Chapter 9. Containers" /></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Facets</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="localization.html">Prev</a> </td><th width="60%" align="center">Chapter 8.
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Localization
|
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</th><td width="20%" align="right"> <a accesskey="n" href="containers.html">Next</a></td></tr></table><hr /></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="std.localization.facet"></a>Facets</h2></div></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="std.localization.facet.ctype"></a>ctype</h3></div></div></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="facet.ctype.impl"></a>Implementation</h4></div></div></div><div class="section"><div class="titlepage"><div><div><h5 class="title"><a id="facet.ctype.impl.spec"></a>Specializations</h5></div></div></div><p>
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For the required specialization <code class="classname">codecvt<wchar_t, char, mbstate_t></code>,
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conversions are made between the internal character set (always UCS4
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on GNU/Linux) and whatever the currently selected locale for the
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||
<code class="code">LC_CTYPE</code> category implements.
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||
</p><p>
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||
The two required specializations are implemented as follows:
|
||
</p><p>
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||
<code class="code">
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ctype<char>
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</code>
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</p><p>
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This is simple specialization. Implementing this was a piece of cake.
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</p><p>
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<code class="code">
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ctype<wchar_t>
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</code>
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||
</p><p>
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||
This specialization, by specifying all the template parameters, pretty
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||
much ties the hands of implementors. As such, the implementation is
|
||
straightforward, involving <code class="function">mcsrtombs</code> for the
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||
conversions between <span class="type">char</span> to <span class="type">wchar_t</span> and
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||
<code class="function">wcsrtombs</code> for conversions between <span class="type">wchar_t</span>
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||
and <span class="type">char</span>.
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||
</p><p>
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||
Neither of these two required specializations deals with Unicode
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||
characters.
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||
</p></div></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="facet.ctype.future"></a>Future</h4></div></div></div><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>
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||
How to deal with the global locale issue?
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||
</p></li><li class="listitem"><p>
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||
How to deal with types other than <span class="type">char</span>, <span class="type">wchar_t</span>?
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||
</p></li><li class="listitem"><p>
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||
Overlap between codecvt/ctype: narrow/widen
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||
</p></li><li class="listitem"><p>
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||
<span class="type">mask</span> typedef in <code class="classname">codecvt_base</code>,
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||
argument types in <span class="type">codecvt</span>. what is know about this type?
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||
</p></li><li class="listitem"><p>
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||
Why mask* argument in codecvt?
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||
</p></li><li class="listitem"><p>
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||
Can this be made (more) generic? is there a simple way to
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||
straighten out the configure-time mess that is a by-product of
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||
this class?
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||
</p></li><li class="listitem"><p>
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||
Get the <span class="type">ctype<wchar_t>::mask</span> stuff under control.
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||
Need to make some kind of static table, and not do lookup every time
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somebody hits the <code class="code">do_is...</code> functions. Too bad we can't
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just redefine <span class="type">mask</span> for
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||
<code class="classname">ctype<wchar_t></code>
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||
</p></li><li class="listitem"><p>
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||
Rename abstract base class. See if just smash-overriding is a
|
||
better approach. Clarify, add sanity to naming.
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||
</p></li></ul></div></div><div class="bibliography"><div class="titlepage"><div><div><h4 class="title"><a id="facet.ctype.biblio"></a>Bibliography</h4></div></div></div><div class="biblioentry"><a id="id-1.3.4.6.3.2.4.2"></a><p><span class="citetitle"><em class="citetitle">
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||
The GNU C Library
|
||
</em>. </span><span class="author"><span class="firstname">Roland</span> <span class="surname">McGrath</span>. </span><span class="author"><span class="firstname">Ulrich</span> <span class="surname">Drepper</span>. </span><span class="copyright">Copyright © 2007 FSF. </span><span class="pagenums">Chapters 6 Character Set Handling and 7 Locales and Internationalization. </span></p></div><div class="biblioentry"><a id="id-1.3.4.6.3.2.4.3"></a><p><span class="citetitle"><em class="citetitle">
|
||
Correspondence
|
||
</em>. </span><span class="author"><span class="firstname">Ulrich</span> <span class="surname">Drepper</span>. </span><span class="copyright">Copyright © 2002 . </span></p></div><div class="biblioentry"><a id="id-1.3.4.6.3.2.4.4"></a><p><span class="citetitle"><em class="citetitle">
|
||
ISO/IEC 14882:1998 Programming languages - C++
|
||
</em>. </span><span class="copyright">Copyright © 1998 ISO. </span></p></div><div class="biblioentry"><a id="id-1.3.4.6.3.2.4.5"></a><p><span class="citetitle"><em class="citetitle">
|
||
ISO/IEC 9899:1999 Programming languages - C
|
||
</em>. </span><span class="copyright">Copyright © 1999 ISO. </span></p></div><div class="biblioentry"><a id="id-1.3.4.6.3.2.4.6"></a><p><span class="title"><em>
|
||
<a class="link" href="http://www.unix.org/version3/ieee_std.html" target="_top">
|
||
The Open Group Base Specifications, Issue 6 (IEEE Std. 1003.1-2004)
|
||
</a>
|
||
</em>. </span><span class="copyright">Copyright © 1999
|
||
The Open Group/The Institute of Electrical and Electronics Engineers, Inc.. </span></p></div><div class="biblioentry"><a id="id-1.3.4.6.3.2.4.7"></a><p><span class="citetitle"><em class="citetitle">
|
||
The C++ Programming Language, Special Edition
|
||
</em>. </span><span class="author"><span class="firstname">Bjarne</span> <span class="surname">Stroustrup</span>. </span><span class="copyright">Copyright © 2000 Addison Wesley, Inc.. </span><span class="pagenums">Appendix D. </span><span class="publisher"><span class="publishername">
|
||
Addison Wesley
|
||
. </span></span></p></div><div class="biblioentry"><a id="id-1.3.4.6.3.2.4.8"></a><p><span class="citetitle"><em class="citetitle">
|
||
Standard C++ IOStreams and Locales
|
||
</em>. </span><span class="subtitle">
|
||
Advanced Programmer's Guide and Reference
|
||
. </span><span class="author"><span class="firstname">Angelika</span> <span class="surname">Langer</span>. </span><span class="author"><span class="firstname">Klaus</span> <span class="surname">Kreft</span>. </span><span class="copyright">Copyright © 2000 Addison Wesley Longman, Inc.. </span><span class="publisher"><span class="publishername">
|
||
Addison Wesley Longman
|
||
. </span></span></p></div></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="std.localization.facet.codecvt"></a>codecvt</h3></div></div></div><p>
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||
The standard class codecvt attempts to address conversions between
|
||
different character encoding schemes. In particular, the standard
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||
attempts to detail conversions between the implementation-defined wide
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||
characters (hereafter referred to as <span class="type">wchar_t</span>) and the standard
|
||
type <span class="type">char</span> that is so beloved in classic <span class="quote">“<span class="quote">C</span>”</span>
|
||
(which can now be referred to as narrow characters.) This document attempts
|
||
to describe how the GNU libstdc++ implementation deals with the conversion
|
||
between wide and narrow characters, and also presents a framework for dealing
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||
with the huge number of other encodings that iconv can convert,
|
||
including Unicode and UTF8. Design issues and requirements are
|
||
addressed, and examples of correct usage for both the required
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||
specializations for wide and narrow characters and the
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||
implementation-provided extended functionality are given.
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||
</p><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="facet.codecvt.req"></a>Requirements</h4></div></div></div><p>
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||
Around page 425 of the C++ Standard, this charming heading comes into view:
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||
</p><div class="blockquote"><blockquote class="blockquote"><p>
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||
22.2.1.5 - Template class codecvt
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||
</p></blockquote></div><p>
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||
The text around the codecvt definition gives some clues:
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||
</p><div class="blockquote"><blockquote class="blockquote"><p>
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||
<span class="emphasis"><em>
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||
-1- The class <code class="code">codecvt<internT,externT,stateT></code> is for use
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||
when converting from one codeset to another, such as from wide characters
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||
to multibyte characters, between wide character encodings such as
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||
Unicode and EUC.
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||
</em></span>
|
||
</p></blockquote></div><p>
|
||
Hmm. So, in some unspecified way, Unicode encodings and
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||
translations between other character sets should be handled by this
|
||
class.
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||
</p><div class="blockquote"><blockquote class="blockquote"><p>
|
||
<span class="emphasis"><em>
|
||
-2- The <span class="type">stateT</span> argument selects the pair of codesets being mapped between.
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||
</em></span>
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||
</p></blockquote></div><p>
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||
Ah ha! Another clue...
|
||
</p><div class="blockquote"><blockquote class="blockquote"><p>
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||
<span class="emphasis"><em>
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||
-3- The instantiations required in the Table 51 (lib.locale.category), namely
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||
<code class="classname">codecvt<wchar_t,char,mbstate_t></code> and
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||
<code class="classname">codecvt<char,char,mbstate_t></code>, convert the
|
||
implementation-defined native character set.
|
||
<code class="classname">codecvt<char,char,mbstate_t></code> implements a
|
||
degenerate conversion; it does not convert at all.
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||
<code class="classname">codecvt<wchar_t,char,mbstate_t></code> converts between
|
||
the native character sets for tiny and wide characters. Instantiations on
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||
<span class="type">mbstate_t</span> perform conversion between encodings known to the library
|
||
implementor. Other encodings can be converted by specializing on a
|
||
user-defined <span class="type">stateT</span> type. The <span class="type">stateT</span> object can
|
||
contain any state that is useful to communicate to or from the specialized
|
||
<code class="function">do_convert</code> member.
|
||
</em></span>
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||
</p></blockquote></div><p>
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||
At this point, a couple points become clear:
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||
</p><p>
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||
One: The standard clearly implies that attempts to add non-required
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||
(yet useful and widely used) conversions need to do so through the
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||
third template parameter, <span class="type">stateT</span>.</p><p>
|
||
Two: The required conversions, by specifying <span class="type">mbstate_t</span> as the
|
||
third template parameter, imply an implementation strategy that is mostly
|
||
(or wholly) based on the underlying C library, and the functions
|
||
<code class="function">mcsrtombs</code> and <code class="function">wcsrtombs</code> in
|
||
particular.</p></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="facet.codecvt.design"></a>Design</h4></div></div></div><div class="section"><div class="titlepage"><div><div><h5 class="title"><a id="codecvt.design.wchar_t_size"></a><span class="type">wchar_t</span> Size</h5></div></div></div><p>
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||
The simple implementation detail of <span class="type">wchar_t</span>'s size seems to
|
||
repeatedly confound people. Many systems use a two byte,
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||
unsigned integral type to represent wide characters, and use an
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||
internal encoding of Unicode or UCS2. (See AIX, Microsoft NT,
|
||
Java, others.) Other systems, use a four byte, unsigned integral
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||
type to represent wide characters, and use an internal encoding
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||
of UCS4. (GNU/Linux systems using glibc, in particular.) The C
|
||
programming language (and thus C++) does not specify a specific
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||
size for the type <span class="type">wchar_t</span>.
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||
</p><p>
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||
Thus, portable C++ code cannot assume a byte size (or endianness) either.
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||
</p></div><div class="section"><div class="titlepage"><div><div><h5 class="title"><a id="codecvt.design.unicode"></a>Support for Unicode</h5></div></div></div><p>
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||
Probably the most frequently asked question about code conversion
|
||
is: "So dudes, what's the deal with Unicode strings?"
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||
The dude part is optional, but apparently the usefulness of
|
||
Unicode strings is pretty widely appreciated. The Unicode character
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||
set (and useful encodings like UTF-8, UCS-4, ISO 8859-10,
|
||
etc etc etc) were not mentioned in the first C++ standard. (The 2011
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||
standard added support for string literals with different encodings
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||
and some library facilities for converting between encodings, but the
|
||
notes below have not been updated to reflect that.)
|
||
</p><p>
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||
A couple of comments:
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||
</p><p>
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||
The thought that all one needs to convert between two arbitrary
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||
codesets is two types and some kind of state argument is
|
||
unfortunate. In particular, encodings may be stateless. The naming
|
||
of the third parameter as <span class="type">stateT</span> is unfortunate, as what is
|
||
really needed is some kind of generalized type that accounts for the
|
||
issues that abstract encodings will need. The minimum information
|
||
that is required includes:
|
||
</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>
|
||
Identifiers for each of the codesets involved in the
|
||
conversion. For example, using the iconv family of functions
|
||
from the Single Unix Specification (what used to be called
|
||
X/Open) hosted on the GNU/Linux operating system allows
|
||
bi-directional mapping between far more than the following
|
||
tantalizing possibilities:
|
||
</p><p>
|
||
(An edited list taken from <code class="code">`iconv --list`</code> on a
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||
Red Hat 6.2/Intel system:
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||
</p><div class="blockquote"><blockquote class="blockquote"><pre class="programlisting">
|
||
8859_1, 8859_9, 10646-1:1993, 10646-1:1993/UCS4, ARABIC, ARABIC7,
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ASCII, EUC-CN, EUC-JP, EUC-KR, EUC-TW, GREEK-CCIcode, GREEK, GREEK7-OLD,
|
||
GREEK7, GREEK8, HEBREW, ISO-8859-1, ISO-8859-2, ISO-8859-3,
|
||
ISO-8859-4, ISO-8859-5, ISO-8859-6, ISO-8859-7, ISO-8859-8,
|
||
ISO-8859-9, ISO-8859-10, ISO-8859-11, ISO-8859-13, ISO-8859-14,
|
||
ISO-8859-15, ISO-10646, ISO-10646/UCS2, ISO-10646/UCS4,
|
||
ISO-10646/UTF-8, ISO-10646/UTF8, SHIFT-JIS, SHIFT_JIS, UCS-2, UCS-4,
|
||
UCS2, UCS4, UNICODE, UNICODEBIG, UNICODELIcodeLE, US-ASCII, US, UTF-8,
|
||
UTF-16, UTF8, UTF16).
|
||
</pre></blockquote></div><p>
|
||
For iconv-based implementations, string literals for each of the
|
||
encodings (i.e. "UCS-2" and "UTF-8") are necessary,
|
||
although for other,
|
||
non-iconv implementations a table of enumerated values or some other
|
||
mechanism may be required.
|
||
</p></li><li class="listitem"><p>
|
||
Maximum length of the identifying string literal.
|
||
</p></li><li class="listitem"><p>
|
||
Some encodings require explicit endian-ness. As such, some kind
|
||
of endian marker or other byte-order marker will be necessary. See
|
||
"Footnotes for C/C++ developers" in Haible for more information on
|
||
UCS-2/Unicode endian issues. (Summary: big endian seems most likely,
|
||
however implementations, most notably Microsoft, vary.)
|
||
</p></li><li class="listitem"><p>
|
||
Types representing the conversion state, for conversions involving
|
||
the machinery in the "C" library, or the conversion descriptor, for
|
||
conversions using iconv (such as the type iconv_t.) Note that the
|
||
conversion descriptor encodes more information than a simple encoding
|
||
state type.
|
||
</p></li><li class="listitem"><p>
|
||
Conversion descriptors for both directions of encoding. (i.e., both
|
||
UCS-2 to UTF-8 and UTF-8 to UCS-2.)
|
||
</p></li><li class="listitem"><p>
|
||
Something to indicate if the conversion requested if valid.
|
||
</p></li><li class="listitem"><p>
|
||
Something to represent if the conversion descriptors are valid.
|
||
</p></li><li class="listitem"><p>
|
||
Some way to enforce strict type checking on the internal and
|
||
external types. As part of this, the size of the internal and
|
||
external types will need to be known.
|
||
</p></li></ul></div></div><div class="section"><div class="titlepage"><div><div><h5 class="title"><a id="codecvt.design.issues"></a>Other Issues</h5></div></div></div><p>
|
||
In addition, multi-threaded and multi-locale environments also impact
|
||
the design and requirements for code conversions. In particular, they
|
||
affect the required specialization
|
||
<code class="classname">codecvt<wchar_t, char, mbstate_t></code>
|
||
when implemented using standard "C" functions.
|
||
</p><p>
|
||
Three problems arise, one big, one of medium importance, and one small.
|
||
</p><p>
|
||
First, the small: <code class="function">mcsrtombs</code> and
|
||
<code class="function">wcsrtombs</code> may not be multithread-safe
|
||
on all systems required by the GNU tools. For GNU/Linux and glibc,
|
||
this is not an issue.
|
||
</p><p>
|
||
Of medium concern, in the grand scope of things, is that the functions
|
||
used to implement this specialization work on null-terminated
|
||
strings. Buffers, especially file buffers, may not be null-terminated,
|
||
thus giving conversions that end prematurely or are otherwise
|
||
incorrect. Yikes!
|
||
</p><p>
|
||
The last, and fundamental problem, is the assumption of a global
|
||
locale for all the "C" functions referenced above. For something like
|
||
C++ iostreams (where codecvt is explicitly used) the notion of
|
||
multiple locales is fundamental. In practice, most users may not run
|
||
into this limitation. However, as a quality of implementation issue,
|
||
the GNU C++ library would like to offer a solution that allows
|
||
multiple locales and or simultaneous usage with computationally
|
||
correct results. In short, libstdc++ is trying to offer, as an
|
||
option, a high-quality implementation, damn the additional complexity!
|
||
</p><p>
|
||
For the required specialization
|
||
<code class="classname">codecvt<wchar_t, char, mbstate_t></code>,
|
||
conversions are made between the internal character set (always UCS4
|
||
on GNU/Linux) and whatever the currently selected locale for the
|
||
LC_CTYPE category implements.
|
||
</p></div></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="facet.codecvt.impl"></a>Implementation</h4></div></div></div><p>
|
||
The two required specializations are implemented as follows:
|
||
</p><p>
|
||
<code class="code">
|
||
codecvt<char, char, mbstate_t>
|
||
</code>
|
||
</p><p>
|
||
This is a degenerate (i.e., does nothing) specialization. Implementing
|
||
this was a piece of cake.
|
||
</p><p>
|
||
<code class="code">
|
||
codecvt<char, wchar_t, mbstate_t>
|
||
</code>
|
||
</p><p>
|
||
This specialization, by specifying all the template parameters, pretty
|
||
much ties the hands of implementors. As such, the implementation is
|
||
straightforward, involving <code class="function">mcsrtombs</code> for the conversions
|
||
between <span class="type">char</span> to <span class="type">wchar_t</span> and
|
||
<code class="function">wcsrtombs</code> for conversions between <span class="type">wchar_t</span>
|
||
and <span class="type">char</span>.
|
||
</p><p>
|
||
Neither of these two required specializations deals with Unicode
|
||
characters. As such, libstdc++ implements a partial specialization
|
||
of the <span class="type">codecvt</span> class with an iconv wrapper class,
|
||
<code class="classname">encoding_state</code> as the third template parameter.
|
||
</p><p>
|
||
This implementation should be standards conformant. First of all, the
|
||
standard explicitly points out that instantiations on the third
|
||
template parameter, <span class="type">stateT</span>, are the proper way to implement
|
||
non-required conversions. Second of all, the standard says (in Chapter
|
||
17) that partial specializations of required classes are A-OK. Third
|
||
of all, the requirements for the <span class="type">stateT</span> type elsewhere in the
|
||
standard (see 21.1.2 traits typedefs) only indicate that this type be copy
|
||
constructible.
|
||
</p><p>
|
||
As such, the type <span class="type">encoding_state</span> is defined as a non-templatized,
|
||
POD type to be used as the third type of a <span class="type">codecvt</span> instantiation.
|
||
This type is just a wrapper class for iconv, and provides an easy interface
|
||
to iconv functionality.
|
||
</p><p>
|
||
There are two constructors for <span class="type">encoding_state</span>:
|
||
</p><p>
|
||
<code class="code">
|
||
encoding_state() : __in_desc(0), __out_desc(0)
|
||
</code>
|
||
</p><p>
|
||
This default constructor sets the internal encoding to some default
|
||
(currently UCS4) and the external encoding to whatever is returned by
|
||
<code class="code">nl_langinfo(CODESET)</code>.
|
||
</p><p>
|
||
<code class="code">
|
||
encoding_state(const char* __int, const char* __ext)
|
||
</code>
|
||
</p><p>
|
||
This constructor takes as parameters string literals that indicate the
|
||
desired internal and external encoding. There are no defaults for
|
||
either argument.
|
||
</p><p>
|
||
One of the issues with iconv is that the string literals identifying
|
||
conversions are not standardized. Because of this, the thought of
|
||
mandating and/or enforcing some set of pre-determined valid
|
||
identifiers seems iffy: thus, a more practical (and non-migraine
|
||
inducing) strategy was implemented: end-users can specify any string
|
||
(subject to a pre-determined length qualifier, currently 32 bytes) for
|
||
encodings. It is up to the user to make sure that these strings are
|
||
valid on the target system.
|
||
</p><p>
|
||
<code class="code">
|
||
void
|
||
_M_init()
|
||
</code>
|
||
</p><p>
|
||
Strangely enough, this member function attempts to open conversion
|
||
descriptors for a given encoding_state object. If the conversion
|
||
descriptors are not valid, the conversion descriptors returned will
|
||
not be valid and the resulting calls to the codecvt conversion
|
||
functions will return error.
|
||
</p><p>
|
||
<code class="code">
|
||
bool
|
||
_M_good()
|
||
</code>
|
||
</p><p>
|
||
Provides a way to see if the given <span class="type">encoding_state</span> object has been
|
||
properly initialized. If the string literals describing the desired
|
||
internal and external encoding are not valid, initialization will
|
||
fail, and this will return false. If the internal and external
|
||
encodings are valid, but <code class="function">iconv_open</code> could not allocate
|
||
conversion descriptors, this will also return false. Otherwise, the object is
|
||
ready to convert and will return true.
|
||
</p><p>
|
||
<code class="code">
|
||
encoding_state(const encoding_state&)
|
||
</code>
|
||
</p><p>
|
||
As iconv allocates memory and sets up conversion descriptors, the copy
|
||
constructor can only copy the member data pertaining to the internal
|
||
and external code conversions, and not the conversion descriptors
|
||
themselves.
|
||
</p><p>
|
||
Definitions for all the required codecvt member functions are provided
|
||
for this specialization, and usage of <code class="code">codecvt<<em class="replaceable"><code>internal
|
||
character type</code></em>, <em class="replaceable"><code>external character type</code></em>, <em class="replaceable"><code>encoding_state</code></em>></code> is consistent with other
|
||
codecvt usage.
|
||
</p></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="facet.codecvt.use"></a>Use</h4></div></div></div><p>A conversion involving a string literal.</p><pre class="programlisting">
|
||
typedef codecvt_base::result result;
|
||
typedef unsigned short unicode_t;
|
||
typedef unicode_t int_type;
|
||
typedef char ext_type;
|
||
typedef encoding_state state_type;
|
||
typedef codecvt<int_type, ext_type, state_type> unicode_codecvt;
|
||
|
||
const ext_type* e_lit = "black pearl jasmine tea";
|
||
int size = strlen(e_lit);
|
||
int_type i_lit_base[24] =
|
||
{ 25088, 27648, 24832, 25344, 27392, 8192, 28672, 25856, 24832, 29184,
|
||
27648, 8192, 27136, 24832, 29440, 27904, 26880, 28160, 25856, 8192, 29696,
|
||
25856, 24832, 2560
|
||
};
|
||
const int_type* i_lit = i_lit_base;
|
||
const ext_type* efrom_next;
|
||
const int_type* ifrom_next;
|
||
ext_type* e_arr = new ext_type[size + 1];
|
||
ext_type* eto_next;
|
||
int_type* i_arr = new int_type[size + 1];
|
||
int_type* ito_next;
|
||
|
||
// construct a locale object with the specialized facet.
|
||
locale loc(locale::classic(), new unicode_codecvt);
|
||
// sanity check the constructed locale has the specialized facet.
|
||
VERIFY( has_facet<unicode_codecvt>(loc) );
|
||
const unicode_codecvt& cvt = use_facet<unicode_codecvt>(loc);
|
||
// convert between const char* and unicode strings
|
||
unicode_codecvt::state_type state01("UNICODE", "ISO_8859-1");
|
||
initialize_state(state01);
|
||
result r1 = cvt.in(state01, e_lit, e_lit + size, efrom_next,
|
||
i_arr, i_arr + size, ito_next);
|
||
VERIFY( r1 == codecvt_base::ok );
|
||
VERIFY( !int_traits::compare(i_arr, i_lit, size) );
|
||
VERIFY( efrom_next == e_lit + size );
|
||
VERIFY( ito_next == i_arr + size );
|
||
</pre></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="facet.codecvt.future"></a>Future</h4></div></div></div><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>
|
||
a. things that are sketchy, or remain unimplemented:
|
||
do_encoding, max_length and length member functions
|
||
are only weakly implemented. I have no idea how to do
|
||
this correctly, and in a generic manner. Nathan?
|
||
</p></li><li class="listitem"><p>
|
||
b. conversions involving <span class="type">std::string</span>
|
||
</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: circle; "><li class="listitem"><p>
|
||
how should operators != and == work for string of
|
||
different/same encoding?
|
||
</p></li><li class="listitem"><p>
|
||
what is equal? A byte by byte comparison or an
|
||
encoding then byte comparison?
|
||
</p></li><li class="listitem"><p>
|
||
conversions between narrow, wide, and unicode strings
|
||
</p></li></ul></div></li><li class="listitem"><p>
|
||
c. conversions involving std::filebuf and std::ostream
|
||
</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: circle; "><li class="listitem"><p>
|
||
how to initialize the state object in a
|
||
standards-conformant manner?
|
||
</p></li><li class="listitem"><p>
|
||
how to synchronize the "C" and "C++"
|
||
conversion information?
|
||
</p></li><li class="listitem"><p>
|
||
wchar_t/char internal buffers and conversions between
|
||
internal/external buffers?
|
||
</p></li></ul></div></li></ul></div></div><div class="bibliography"><div class="titlepage"><div><div><h4 class="title"><a id="facet.codecvt.biblio"></a>Bibliography</h4></div></div></div><div class="biblioentry"><a id="id-1.3.4.6.3.3.8.2"></a><p><span class="citetitle"><em class="citetitle">
|
||
The GNU C Library
|
||
</em>. </span><span class="author"><span class="firstname">Roland</span> <span class="surname">McGrath</span>. </span><span class="author"><span class="firstname">Ulrich</span> <span class="surname">Drepper</span>. </span><span class="copyright">Copyright © 2007 FSF. </span><span class="pagenums">
|
||
Chapters 6 Character Set Handling and 7 Locales and Internationalization
|
||
. </span></p></div><div class="biblioentry"><a id="id-1.3.4.6.3.3.8.3"></a><p><span class="citetitle"><em class="citetitle">
|
||
Correspondence
|
||
</em>. </span><span class="author"><span class="firstname">Ulrich</span> <span class="surname">Drepper</span>. </span><span class="copyright">Copyright © 2002 . </span></p></div><div class="biblioentry"><a id="id-1.3.4.6.3.3.8.4"></a><p><span class="citetitle"><em class="citetitle">
|
||
ISO/IEC 14882:1998 Programming languages - C++
|
||
</em>. </span><span class="copyright">Copyright © 1998 ISO. </span></p></div><div class="biblioentry"><a id="id-1.3.4.6.3.3.8.5"></a><p><span class="citetitle"><em class="citetitle">
|
||
ISO/IEC 9899:1999 Programming languages - C
|
||
</em>. </span><span class="copyright">Copyright © 1999 ISO. </span></p></div><div class="biblioentry"><a id="id-1.3.4.6.3.3.8.6"></a><p><span class="title"><em>
|
||
<a class="link" href="http://pubs.opengroup.org/onlinepubs/9699919799/" target="_top">
|
||
System Interface Definitions, Issue 7 (IEEE Std. 1003.1-2008)
|
||
</a>
|
||
</em>. </span><span class="copyright">Copyright © 2008
|
||
The Open Group/The Institute of Electrical and Electronics
|
||
Engineers, Inc.
|
||
. </span></p></div><div class="biblioentry"><a id="id-1.3.4.6.3.3.8.7"></a><p><span class="citetitle"><em class="citetitle">
|
||
The C++ Programming Language, Special Edition
|
||
</em>. </span><span class="author"><span class="firstname">Bjarne</span> <span class="surname">Stroustrup</span>. </span><span class="copyright">Copyright © 2000 Addison Wesley, Inc.. </span><span class="pagenums">Appendix D. </span><span class="publisher"><span class="publishername">
|
||
Addison Wesley
|
||
. </span></span></p></div><div class="biblioentry"><a id="id-1.3.4.6.3.3.8.8"></a><p><span class="citetitle"><em class="citetitle">
|
||
Standard C++ IOStreams and Locales
|
||
</em>. </span><span class="subtitle">
|
||
Advanced Programmer's Guide and Reference
|
||
. </span><span class="author"><span class="firstname">Angelika</span> <span class="surname">Langer</span>. </span><span class="author"><span class="firstname">Klaus</span> <span class="surname">Kreft</span>. </span><span class="copyright">Copyright © 2000 Addison Wesley Longman, Inc.. </span><span class="publisher"><span class="publishername">
|
||
Addison Wesley Longman
|
||
. </span></span></p></div><div class="biblioentry"><a id="id-1.3.4.6.3.3.8.9"></a><p><span class="title"><em>
|
||
<a class="link" href="http://www.lysator.liu.se/c/na1.html" target="_top">
|
||
A brief description of Normative Addendum 1
|
||
</a>
|
||
</em>. </span><span class="author"><span class="firstname">Clive</span> <span class="surname">Feather</span>. </span><span class="pagenums">Extended Character Sets. </span></p></div><div class="biblioentry"><a id="id-1.3.4.6.3.3.8.10"></a><p><span class="title"><em>
|
||
<a class="link" href="http://tldp.org/HOWTO/Unicode-HOWTO.html" target="_top">
|
||
The Unicode HOWTO
|
||
</a>
|
||
</em>. </span><span class="author"><span class="firstname">Bruno</span> <span class="surname">Haible</span>. </span></p></div><div class="biblioentry"><a id="id-1.3.4.6.3.3.8.11"></a><p><span class="title"><em>
|
||
<a class="link" href="https://www.cl.cam.ac.uk/~mgk25/unicode.html" target="_top">
|
||
UTF-8 and Unicode FAQ for Unix/Linux
|
||
</a>
|
||
</em>. </span><span class="author"><span class="firstname">Markus</span> <span class="surname">Khun</span>. </span></p></div></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="std.localization.facet.messages"></a>messages</h3></div></div></div><p>
|
||
The <code class="classname">std::messages</code> facet implements message retrieval functionality
|
||
equivalent to Java's <code class="classname">java.text.MessageFormat</code> using either GNU <code class="function">gettext</code>
|
||
or IEEE 1003.1-200 functions.
|
||
</p><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="facet.messages.req"></a>Requirements</h4></div></div></div><p>
|
||
The <code class="classname">std::messages</code> facet is probably the most vaguely defined facet in
|
||
the standard library. It's assumed that this facility was built into
|
||
the standard library in order to convert string literals from one
|
||
locale to the other. For instance, converting the "C" locale's
|
||
<code class="code">const char* c = "please"</code> to a German-localized <code class="code">"bitte"</code>
|
||
during program execution.
|
||
</p><div class="blockquote"><blockquote class="blockquote"><p>
|
||
22.2.7.1 - Template class messages [lib.locale.messages]
|
||
</p></blockquote></div><p>
|
||
This class has three public member functions, which directly
|
||
correspond to three protected virtual member functions.
|
||
</p><p>
|
||
The public member functions are:
|
||
</p><p>
|
||
<code class="code">catalog open(const string&, const locale&) const</code>
|
||
</p><p>
|
||
<code class="code">string_type get(catalog, int, int, const string_type&) const</code>
|
||
</p><p>
|
||
<code class="code">void close(catalog) const</code>
|
||
</p><p>
|
||
While the virtual functions are:
|
||
</p><p>
|
||
<code class="code">catalog do_open(const string& name, const locale& loc) const</code>
|
||
</p><div class="blockquote"><blockquote class="blockquote"><p>
|
||
<span class="emphasis"><em>
|
||
-1- Returns: A value that may be passed to <code class="code">get()</code> to retrieve a
|
||
message, from the message catalog identified by the string <code class="code">name</code>
|
||
according to an implementation-defined mapping. The result can be used
|
||
until it is passed to <code class="code">close()</code>. Returns a value less than 0 if no such
|
||
catalog can be opened.
|
||
</em></span>
|
||
</p></blockquote></div><p>
|
||
<code class="code">string_type do_get(catalog cat, int set , int msgid, const string_type& dfault) const</code>
|
||
</p><div class="blockquote"><blockquote class="blockquote"><p>
|
||
<span class="emphasis"><em>
|
||
-3- Requires: A catalog <code class="code">cat</code> obtained from <code class="code">open()</code> and not yet closed.
|
||
-4- Returns: A message identified by arguments <code class="code">set</code>, <code class="code">msgid</code>, and <code class="code">dfault</code>,
|
||
according to an implementation-defined mapping. If no such message can
|
||
be found, returns <code class="code">dfault</code>.
|
||
</em></span>
|
||
</p></blockquote></div><p>
|
||
<code class="code">void do_close(catalog cat) const</code>
|
||
</p><div class="blockquote"><blockquote class="blockquote"><p>
|
||
<span class="emphasis"><em>
|
||
-5- Requires: A catalog cat obtained from <code class="code">open()</code> and not yet closed.
|
||
-6- Effects: Releases unspecified resources associated with <code class="code">cat</code>.
|
||
-7- Notes: The limit on such resources, if any, is implementation-defined.
|
||
</em></span>
|
||
</p></blockquote></div></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="facet.messages.design"></a>Design</h4></div></div></div><p>
|
||
A couple of notes on the standard.
|
||
</p><p>
|
||
First, why is <code class="code">messages_base::catalog</code> specified as a typedef
|
||
to int? This makes sense for implementations that use
|
||
<code class="code">catopen</code> and define <code class="code">nl_catd</code> as int, but not for
|
||
others. Fortunately, it's not heavily used and so only a minor irritant.
|
||
This has been reported as a possible defect in the standard (LWG 2028).
|
||
</p><p>
|
||
Second, by making the member functions <code class="code">const</code>, it is
|
||
impossible to save state in them. Thus, storing away information used
|
||
in the 'open' member function for use in 'get' is impossible. This is
|
||
unfortunate.
|
||
</p><p>
|
||
The 'open' member function in particular seems to be oddly
|
||
designed. The signature seems quite peculiar. Why specify a <code class="code">const
|
||
string& </code> argument, for instance, instead of just <code class="code">const
|
||
char*</code>? Or, why specify a <code class="code">const locale&</code> argument that is
|
||
to be used in the 'get' member function? How, exactly, is this locale
|
||
argument useful? What was the intent? It might make sense if a locale
|
||
argument was associated with a given default message string in the
|
||
'open' member function, for instance. Quite murky and unclear, on
|
||
reflection.
|
||
</p><p>
|
||
Lastly, it seems odd that messages, which explicitly require code
|
||
conversion, don't use the codecvt facet. Because the messages facet
|
||
has only one template parameter, it is assumed that ctype, and not
|
||
codecvt, is to be used to convert between character sets.
|
||
</p><p>
|
||
It is implicitly assumed that the locale for the default message
|
||
string in 'get' is in the "C" locale. Thus, all source code is assumed
|
||
to be written in English, so translations are always from "en_US" to
|
||
other, explicitly named locales.
|
||
</p></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="facet.messages.impl"></a>Implementation</h4></div></div></div><div class="section"><div class="titlepage"><div><div><h5 class="title"><a id="messages.impl.models"></a>Models</h5></div></div></div><p>
|
||
This is a relatively simple class, on the face of it. The standard
|
||
specifies very little in concrete terms, so generic
|
||
implementations that are conforming yet do very little are the
|
||
norm. Adding functionality that would be useful to programmers and
|
||
comparable to Java's java.text.MessageFormat takes a bit of work,
|
||
and is highly dependent on the capabilities of the underlying
|
||
operating system.
|
||
</p><p>
|
||
Three different mechanisms have been provided, selectable via
|
||
configure flags:
|
||
</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>
|
||
generic
|
||
</p><p>
|
||
This model does very little, and is what is used by default.
|
||
</p></li><li class="listitem"><p>
|
||
gnu
|
||
</p><p>
|
||
The gnu model is complete and fully tested. It's based on the
|
||
GNU gettext package, which is part of glibc. It uses the
|
||
functions <code class="code">textdomain, bindtextdomain, gettext</code> to
|
||
implement full functionality. Creating message catalogs is a
|
||
relatively straight-forward process and is lightly documented
|
||
below, and fully documented in gettext's distributed
|
||
documentation.
|
||
</p></li><li class="listitem"><p>
|
||
ieee_1003.1-200x
|
||
</p><p>
|
||
This is a complete, though untested, implementation based on
|
||
the IEEE standard. The functions <code class="code">catopen, catgets,
|
||
catclose</code> are used to retrieve locale-specific messages
|
||
given the appropriate message catalogs that have been
|
||
constructed for their use. Note, the script <code class="code">
|
||
po2msg.sed</code> that is part of the gettext distribution can
|
||
convert gettext catalogs into catalogs that
|
||
<code class="code">catopen</code> can use.
|
||
</p></li></ul></div><p>
|
||
A new, standards-conformant non-virtual member function signature was
|
||
added for 'open' so that a directory could be specified with a given
|
||
message catalog. This simplifies calling conventions for the gnu
|
||
model.
|
||
</p></div><div class="section"><div class="titlepage"><div><div><h5 class="title"><a id="messages.impl.gnu"></a>The GNU Model</h5></div></div></div><p>
|
||
The messages facet, because it is retrieving and converting
|
||
between characters sets, depends on the ctype and perhaps the
|
||
codecvt facet in a given locale. In addition, underlying "C"
|
||
library locale support is necessary for more than just the
|
||
<code class="code">LC_MESSAGES</code> mask: <code class="code">LC_CTYPE</code> is also
|
||
necessary. To avoid any unpleasantness, all bits of the "C" mask
|
||
(i.e. <code class="code">LC_ALL</code>) are set before retrieving messages.
|
||
</p><p>
|
||
Making the message catalogs can be initially tricky, but become
|
||
quite simple with practice. For complete info, see the gettext
|
||
documentation. Here's an idea of what is required:
|
||
</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>
|
||
Make a source file with the required string literals that need
|
||
to be translated. See <code class="code">intl/string_literals.cc</code> for
|
||
an example.
|
||
</p></li><li class="listitem"><p>
|
||
Make initial catalog (see "4 Making the PO Template File" from
|
||
the gettext docs).</p><p>
|
||
<code class="code"> xgettext --c++ --debug string_literals.cc -o libstdc++.pot </code>
|
||
</p></li><li class="listitem"><p>Make language and country-specific locale catalogs.</p><p>
|
||
<code class="code">cp libstdc++.pot fr_FR.po</code>
|
||
</p><p>
|
||
<code class="code">cp libstdc++.pot de_DE.po</code>
|
||
</p></li><li class="listitem"><p>
|
||
Edit localized catalogs in emacs so that strings are
|
||
translated.
|
||
</p><p>
|
||
<code class="code">emacs fr_FR.po</code>
|
||
</p></li><li class="listitem"><p>Make the binary mo files.</p><p>
|
||
<code class="code">msgfmt fr_FR.po -o fr_FR.mo</code>
|
||
</p><p>
|
||
<code class="code">msgfmt de_DE.po -o de_DE.mo</code>
|
||
</p></li><li class="listitem"><p>Copy the binary files into the correct directory structure.</p><p>
|
||
<code class="code">cp fr_FR.mo (dir)/fr_FR/LC_MESSAGES/libstdc++.mo</code>
|
||
</p><p>
|
||
<code class="code">cp de_DE.mo (dir)/de_DE/LC_MESSAGES/libstdc++.mo</code>
|
||
</p></li><li class="listitem"><p>Use the new message catalogs.</p><p>
|
||
<code class="code">locale loc_de("de_DE");</code>
|
||
</p><p>
|
||
<code class="code">
|
||
use_facet<messages<char> >(loc_de).open("libstdc++", locale(), dir);
|
||
</code>
|
||
</p></li></ul></div></div></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="facet.messages.use"></a>Use</h4></div></div></div><p>
|
||
A simple example using the GNU model of message conversion.
|
||
</p><pre class="programlisting">
|
||
#include <iostream>
|
||
#include <locale>
|
||
using namespace std;
|
||
|
||
void test01()
|
||
{
|
||
typedef messages<char>::catalog catalog;
|
||
const char* dir =
|
||
"/mnt/egcs/build/i686-pc-linux-gnu/libstdc++/po/share/locale";
|
||
const locale loc_de("de_DE");
|
||
const messages<char>& mssg_de = use_facet<messages<char> >(loc_de);
|
||
|
||
catalog cat_de = mssg_de.open("libstdc++", loc_de, dir);
|
||
string s01 = mssg_de.get(cat_de, 0, 0, "please");
|
||
string s02 = mssg_de.get(cat_de, 0, 0, "thank you");
|
||
cout << "please in german:" << s01 << '\n';
|
||
cout << "thank you in german:" << s02 << '\n';
|
||
mssg_de.close(cat_de);
|
||
}
|
||
</pre></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="facet.messages.future"></a>Future</h4></div></div></div><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>
|
||
Things that are sketchy, or remain unimplemented:
|
||
</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: circle; "><li class="listitem"><p>
|
||
_M_convert_from_char, _M_convert_to_char are in flux,
|
||
depending on how the library ends up doing character set
|
||
conversions. It might not be possible to do a real character
|
||
set based conversion, due to the fact that the template
|
||
parameter for messages is not enough to instantiate the
|
||
codecvt facet (1 supplied, need at least 2 but would prefer
|
||
3).
|
||
</p></li><li class="listitem"><p>
|
||
There are issues with gettext needing the global locale set
|
||
to extract a message. This dependence on the global locale
|
||
makes the current "gnu" model non MT-safe. Future versions
|
||
of glibc, i.e. glibc 2.3.x will fix this, and the C++ library
|
||
bits are already in place.
|
||
</p></li></ul></div></li><li class="listitem"><p>
|
||
Development versions of the GNU "C" library, glibc 2.3 will allow
|
||
a more efficient, MT implementation of std::messages, and will
|
||
allow the removal of the _M_name_messages data member. If this is
|
||
done, it will change the library ABI. The C++ parts to support
|
||
glibc 2.3 have already been coded, but are not in use: once this
|
||
version of the "C" library is released, the marked parts of the
|
||
messages implementation can be switched over to the new "C"
|
||
library functionality.
|
||
</p></li><li class="listitem"><p>
|
||
At some point in the near future, std::numpunct will probably use
|
||
std::messages facilities to implement truename/falsename
|
||
correctly. This is currently not done, but entries in
|
||
libstdc++.pot have already been made for "true" and "false" string
|
||
literals, so all that remains is the std::numpunct coding and the
|
||
configure/make hassles to make the installed library search its
|
||
own catalog. Currently the libstdc++.mo catalog is only searched
|
||
for the testsuite cases involving messages members.
|
||
</p></li><li class="listitem"><p> The following member functions:</p><p>
|
||
<code class="code">
|
||
catalog
|
||
open(const basic_string<char>& __s, const locale& __loc) const
|
||
</code>
|
||
</p><p>
|
||
<code class="code">
|
||
catalog
|
||
open(const basic_string<char>&, const locale&, const char*) const;
|
||
</code>
|
||
</p><p>
|
||
Don't actually return a "value less than 0 if no such catalog
|
||
can be opened" as required by the standard in the "gnu"
|
||
model. As of this writing, it is unknown how to query to see
|
||
if a specified message catalog exists using the gettext
|
||
package.
|
||
</p></li></ul></div></div><div class="bibliography"><div class="titlepage"><div><div><h4 class="title"><a id="facet.messages.biblio"></a>Bibliography</h4></div></div></div><div class="biblioentry"><a id="id-1.3.4.6.3.4.8.2"></a><p><span class="citetitle"><em class="citetitle">
|
||
The GNU C Library
|
||
</em>. </span><span class="author"><span class="firstname">Roland</span> <span class="surname">McGrath</span>. </span><span class="author"><span class="firstname">Ulrich</span> <span class="surname">Drepper</span>. </span><span class="copyright">Copyright © 2007 FSF. </span><span class="pagenums">Chapters 6 Character Set Handling, and 7 Locales and Internationalization
|
||
. </span></p></div><div class="biblioentry"><a id="id-1.3.4.6.3.4.8.3"></a><p><span class="citetitle"><em class="citetitle">
|
||
Correspondence
|
||
</em>. </span><span class="author"><span class="firstname">Ulrich</span> <span class="surname">Drepper</span>. </span><span class="copyright">Copyright © 2002 . </span></p></div><div class="biblioentry"><a id="id-1.3.4.6.3.4.8.4"></a><p><span class="citetitle"><em class="citetitle">
|
||
ISO/IEC 14882:1998 Programming languages - C++
|
||
</em>. </span><span class="copyright">Copyright © 1998 ISO. </span></p></div><div class="biblioentry"><a id="id-1.3.4.6.3.4.8.5"></a><p><span class="citetitle"><em class="citetitle">
|
||
ISO/IEC 9899:1999 Programming languages - C
|
||
</em>. </span><span class="copyright">Copyright © 1999 ISO. </span></p></div><div class="biblioentry"><a id="id-1.3.4.6.3.4.8.6"></a><p><span class="title"><em>
|
||
<a class="link" href="http://pubs.opengroup.org/onlinepubs/9699919799/" target="_top">
|
||
System Interface Definitions, Issue 7 (IEEE Std. 1003.1-2008)
|
||
</a>
|
||
</em>. </span><span class="copyright">Copyright © 2008
|
||
The Open Group/The Institute of Electrical and Electronics
|
||
Engineers, Inc.
|
||
. </span></p></div><div class="biblioentry"><a id="id-1.3.4.6.3.4.8.7"></a><p><span class="citetitle"><em class="citetitle">
|
||
The C++ Programming Language, Special Edition
|
||
</em>. </span><span class="author"><span class="firstname">Bjarne</span> <span class="surname">Stroustrup</span>. </span><span class="copyright">Copyright © 2000 Addison Wesley, Inc.. </span><span class="pagenums">Appendix D. </span><span class="publisher"><span class="publishername">
|
||
Addison Wesley
|
||
. </span></span></p></div><div class="biblioentry"><a id="id-1.3.4.6.3.4.8.8"></a><p><span class="citetitle"><em class="citetitle">
|
||
Standard C++ IOStreams and Locales
|
||
</em>. </span><span class="subtitle">
|
||
Advanced Programmer's Guide and Reference
|
||
. </span><span class="author"><span class="firstname">Angelika</span> <span class="surname">Langer</span>. </span><span class="author"><span class="firstname">Klaus</span> <span class="surname">Kreft</span>. </span><span class="copyright">Copyright © 2000 Addison Wesley Longman, Inc.. </span><span class="publisher"><span class="publishername">
|
||
Addison Wesley Longman
|
||
. </span></span></p></div><div class="biblioentry"><a id="id-1.3.4.6.3.4.8.9"></a><p><span class="title"><em>
|
||
<a class="link" href="https://www.oracle.com/technetwork/java/api/index.html" target="_top">
|
||
API Specifications, Java Platform
|
||
</a>
|
||
</em>. </span><span class="pagenums">java.util.Properties, java.text.MessageFormat,
|
||
java.util.Locale, java.util.ResourceBundle
|
||
. </span></p></div><div class="biblioentry"><a id="id-1.3.4.6.3.4.8.10"></a><p><span class="title"><em>
|
||
<a class="link" href="https://www.gnu.org/software/gettext/" target="_top">
|
||
GNU gettext tools, version 0.10.38, Native Language Support
|
||
Library and Tools.
|
||
</a>
|
||
</em>. </span></p></div></div></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="localization.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="localization.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="containers.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Chapter 8.
|
||
Localization
|
||
|
||
</td><td width="20%" align="center"><a accesskey="h" href="../index.html">Home</a></td><td width="40%" align="right" valign="top"> Chapter 9.
|
||
Containers
|
||
|
||
</td></tr></table></div></body></html> |