codecvt.h
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// Locale support (codecvt) -*- C++ -*-
// Copyright (C) 2000-2013 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.
// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
// <http://www.gnu.org/licenses/>.
/** @file bits/codecvt.h
* This is an internal header file, included by other library headers.
* Do not attempt to use it directly. @headername{locale}
*/
//
// ISO C++ 14882: 22.2.1.5 Template class codecvt
//
// Written by Benjamin Kosnik <bkoz@redhat.com>
#ifndef _CODECVT_H
#define _CODECVT_H 1
#pragma GCC system_header
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
/// Empty base class for codecvt facet [22.2.1.5].
class codecvt_base
{
public:
enum result
{
ok,
partial,
error,
noconv
};
};
/**
* @brief Common base for codecvt functions.
*
* This template class provides implementations of the public functions
* that forward to the protected virtual functions.
*
* This template also provides abstract stubs for the protected virtual
* functions.
*/
template<typename _InternT, typename _ExternT, typename _StateT>
class __codecvt_abstract_base
: public locale::facet, public codecvt_base
{
public:
// Types:
typedef codecvt_base::result result;
typedef _InternT intern_type;
typedef _ExternT extern_type;
typedef _StateT state_type;
// 22.2.1.5.1 codecvt members
/**
* @brief Convert from internal to external character set.
*
* Converts input string of intern_type to output string of
* extern_type. This is analogous to wcsrtombs. It does this by
* calling codecvt::do_out.
*
* The source and destination character sets are determined by the
* facet's locale, internal and external types.
*
* The characters in [from,from_end) are converted and written to
* [to,to_end). from_next and to_next are set to point to the
* character following the last successfully converted character,
* respectively. If the result needed no conversion, from_next and
* to_next are not affected.
*
* The @a state argument should be initialized if the input is at the
* beginning and carried from a previous call if continuing
* conversion. There are no guarantees about how @a state is used.
*
* The result returned is a member of codecvt_base::result. If
* all the input is converted, returns codecvt_base::ok. If no
* conversion is necessary, returns codecvt_base::noconv. If
* the input ends early or there is insufficient space in the
* output, returns codecvt_base::partial. Otherwise the
* conversion failed and codecvt_base::error is returned.
*
* @param __state Persistent conversion state data.
* @param __from Start of input.
* @param __from_end End of input.
* @param __from_next Returns start of unconverted data.
* @param __to Start of output buffer.
* @param __to_end End of output buffer.
* @param __to_next Returns start of unused output area.
* @return codecvt_base::result.
*/
result
out(state_type& __state, const intern_type* __from,
const intern_type* __from_end, const intern_type*& __from_next,
extern_type* __to, extern_type* __to_end,
extern_type*& __to_next) const
{
return this->do_out(__state, __from, __from_end, __from_next,
__to, __to_end, __to_next);
}
/**
* @brief Reset conversion state.
*
* Writes characters to output that would restore @a state to initial
* conditions. The idea is that if a partial conversion occurs, then
* the converting the characters written by this function would leave
* the state in initial conditions, rather than partial conversion
* state. It does this by calling codecvt::do_unshift().
*
* For example, if 4 external characters always converted to 1 internal
* character, and input to in() had 6 external characters with state
* saved, this function would write two characters to the output and
* set the state to initialized conditions.
*
* The source and destination character sets are determined by the
* facet's locale, internal and external types.
*
* The result returned is a member of codecvt_base::result. If the
* state could be reset and data written, returns codecvt_base::ok. If
* no conversion is necessary, returns codecvt_base::noconv. If the
* output has insufficient space, returns codecvt_base::partial.
* Otherwise the reset failed and codecvt_base::error is returned.
*
* @param __state Persistent conversion state data.
* @param __to Start of output buffer.
* @param __to_end End of output buffer.
* @param __to_next Returns start of unused output area.
* @return codecvt_base::result.
*/
result
unshift(state_type& __state, extern_type* __to, extern_type* __to_end,
extern_type*& __to_next) const
{ return this->do_unshift(__state, __to,__to_end,__to_next); }
/**
* @brief Convert from external to internal character set.
*
* Converts input string of extern_type to output string of
* intern_type. This is analogous to mbsrtowcs. It does this by
* calling codecvt::do_in.
*
* The source and destination character sets are determined by the
* facet's locale, internal and external types.
*
* The characters in [from,from_end) are converted and written to
* [to,to_end). from_next and to_next are set to point to the
* character following the last successfully converted character,
* respectively. If the result needed no conversion, from_next and
* to_next are not affected.
*
* The @a state argument should be initialized if the input is at the
* beginning and carried from a previous call if continuing
* conversion. There are no guarantees about how @a state is used.
*
* The result returned is a member of codecvt_base::result. If
* all the input is converted, returns codecvt_base::ok. If no
* conversion is necessary, returns codecvt_base::noconv. If
* the input ends early or there is insufficient space in the
* output, returns codecvt_base::partial. Otherwise the
* conversion failed and codecvt_base::error is returned.
*
* @param __state Persistent conversion state data.
* @param __from Start of input.
* @param __from_end End of input.
* @param __from_next Returns start of unconverted data.
* @param __to Start of output buffer.
* @param __to_end End of output buffer.
* @param __to_next Returns start of unused output area.
* @return codecvt_base::result.
*/
result
in(state_type& __state, const extern_type* __from,
const extern_type* __from_end, const extern_type*& __from_next,
intern_type* __to, intern_type* __to_end,
intern_type*& __to_next) const
{
return this->do_in(__state, __from, __from_end, __from_next,
__to, __to_end, __to_next);
}
int
encoding() const throw()
{ return this->do_encoding(); }
bool
always_noconv() const throw()
{ return this->do_always_noconv(); }
int
length(state_type& __state, const extern_type* __from,
const extern_type* __end, size_t __max) const
{ return this->do_length(__state, __from, __end, __max); }
int
max_length() const throw()
{ return this->do_max_length(); }
protected:
explicit
__codecvt_abstract_base(size_t __refs = 0) : locale::facet(__refs) { }
virtual
~__codecvt_abstract_base() { }
/**
* @brief Convert from internal to external character set.
*
* Converts input string of intern_type to output string of
* extern_type. This function is a hook for derived classes to change
* the value returned. @see out for more information.
*/
virtual result
do_out(state_type& __state, const intern_type* __from,
const intern_type* __from_end, const intern_type*& __from_next,
extern_type* __to, extern_type* __to_end,
extern_type*& __to_next) const = 0;
virtual result
do_unshift(state_type& __state, extern_type* __to,
extern_type* __to_end, extern_type*& __to_next) const = 0;
virtual result
do_in(state_type& __state, const extern_type* __from,
const extern_type* __from_end, const extern_type*& __from_next,
intern_type* __to, intern_type* __to_end,
intern_type*& __to_next) const = 0;
virtual int
do_encoding() const throw() = 0;
virtual bool
do_always_noconv() const throw() = 0;
virtual int
do_length(state_type&, const extern_type* __from,
const extern_type* __end, size_t __max) const = 0;
virtual int
do_max_length() const throw() = 0;
};
/**
* @brief Primary class template codecvt.
* @ingroup locales
*
* NB: Generic, mostly useless implementation.
*
*/
template<typename _InternT, typename _ExternT, typename _StateT>
class codecvt
: public __codecvt_abstract_base<_InternT, _ExternT, _StateT>
{
public:
// Types:
typedef codecvt_base::result result;
typedef _InternT intern_type;
typedef _ExternT extern_type;
typedef _StateT state_type;
protected:
__c_locale _M_c_locale_codecvt;
public:
static locale::id id;
explicit
codecvt(size_t __refs = 0)
: __codecvt_abstract_base<_InternT, _ExternT, _StateT> (__refs),
_M_c_locale_codecvt(0)
{ }
explicit
codecvt(__c_locale __cloc, size_t __refs = 0);
protected:
virtual
~codecvt() { }
virtual result
do_out(state_type& __state, const intern_type* __from,
const intern_type* __from_end, const intern_type*& __from_next,
extern_type* __to, extern_type* __to_end,
extern_type*& __to_next) const;
virtual result
do_unshift(state_type& __state, extern_type* __to,
extern_type* __to_end, extern_type*& __to_next) const;
virtual result
do_in(state_type& __state, const extern_type* __from,
const extern_type* __from_end, const extern_type*& __from_next,
intern_type* __to, intern_type* __to_end,
intern_type*& __to_next) const;
virtual int
do_encoding() const throw();
virtual bool
do_always_noconv() const throw();
virtual int
do_length(state_type&, const extern_type* __from,
const extern_type* __end, size_t __max) const;
virtual int
do_max_length() const throw();
};
template<typename _InternT, typename _ExternT, typename _StateT>
locale::id codecvt<_InternT, _ExternT, _StateT>::id;
/// class codecvt<char, char, mbstate_t> specialization.
template<>
class codecvt<char, char, mbstate_t>
: public __codecvt_abstract_base<char, char, mbstate_t>
{
public:
// Types:
typedef char intern_type;
typedef char extern_type;
typedef mbstate_t state_type;
protected:
__c_locale _M_c_locale_codecvt;
public:
static locale::id id;
explicit
codecvt(size_t __refs = 0);
explicit
codecvt(__c_locale __cloc, size_t __refs = 0);
protected:
virtual
~codecvt();
virtual result
do_out(state_type& __state, const intern_type* __from,
const intern_type* __from_end, const intern_type*& __from_next,
extern_type* __to, extern_type* __to_end,
extern_type*& __to_next) const;
virtual result
do_unshift(state_type& __state, extern_type* __to,
extern_type* __to_end, extern_type*& __to_next) const;
virtual result
do_in(state_type& __state, const extern_type* __from,
const extern_type* __from_end, const extern_type*& __from_next,
intern_type* __to, intern_type* __to_end,
intern_type*& __to_next) const;
virtual int
do_encoding() const throw();
virtual bool
do_always_noconv() const throw();
virtual int
do_length(state_type&, const extern_type* __from,
const extern_type* __end, size_t __max) const;
virtual int
do_max_length() const throw();
};
#ifdef _GLIBCXX_USE_WCHAR_T
/// class codecvt<wchar_t, char, mbstate_t> specialization.
template<>
class codecvt<wchar_t, char, mbstate_t>
: public __codecvt_abstract_base<wchar_t, char, mbstate_t>
{
public:
// Types:
typedef wchar_t intern_type;
typedef char extern_type;
typedef mbstate_t state_type;
protected:
__c_locale _M_c_locale_codecvt;
public:
static locale::id id;
explicit
codecvt(size_t __refs = 0);
explicit
codecvt(__c_locale __cloc, size_t __refs = 0);
protected:
virtual
~codecvt();
virtual result
do_out(state_type& __state, const intern_type* __from,
const intern_type* __from_end, const intern_type*& __from_next,
extern_type* __to, extern_type* __to_end,
extern_type*& __to_next) const;
virtual result
do_unshift(state_type& __state,
extern_type* __to, extern_type* __to_end,
extern_type*& __to_next) const;
virtual result
do_in(state_type& __state,
const extern_type* __from, const extern_type* __from_end,
const extern_type*& __from_next,
intern_type* __to, intern_type* __to_end,
intern_type*& __to_next) const;
virtual
int do_encoding() const throw();
virtual
bool do_always_noconv() const throw();
virtual
int do_length(state_type&, const extern_type* __from,
const extern_type* __end, size_t __max) const;
virtual int
do_max_length() const throw();
};
#endif //_GLIBCXX_USE_WCHAR_T
/// class codecvt_byname [22.2.1.6].
template<typename _InternT, typename _ExternT, typename _StateT>
class codecvt_byname : public codecvt<_InternT, _ExternT, _StateT>
{
public:
explicit
codecvt_byname(const char* __s, size_t __refs = 0)
: codecvt<_InternT, _ExternT, _StateT>(__refs)
{
if (__builtin_strcmp(__s, "C") != 0
&& __builtin_strcmp(__s, "POSIX") != 0)
{
this->_S_destroy_c_locale(this->_M_c_locale_codecvt);
this->_S_create_c_locale(this->_M_c_locale_codecvt, __s);
}
}
protected:
virtual
~codecvt_byname() { }
};
// Inhibit implicit instantiations for required instantiations,
// which are defined via explicit instantiations elsewhere.
#if _GLIBCXX_EXTERN_TEMPLATE
extern template class codecvt_byname<char, char, mbstate_t>;
extern template
const codecvt<char, char, mbstate_t>&
use_facet<codecvt<char, char, mbstate_t> >(const locale&);
extern template
bool
has_facet<codecvt<char, char, mbstate_t> >(const locale&);
#ifdef _GLIBCXX_USE_WCHAR_T
extern template class codecvt_byname<wchar_t, char, mbstate_t>;
extern template
const codecvt<wchar_t, char, mbstate_t>&
use_facet<codecvt<wchar_t, char, mbstate_t> >(const locale&);
extern template
bool
has_facet<codecvt<wchar_t, char, mbstate_t> >(const locale&);
#endif
#endif
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace std
#endif // _CODECVT_H