codecvt_specializations.h
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// Locale support (codecvt) -*- C++ -*-
// Copyright (C) 2000-2021 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/>.
//
// ISO C++ 14882: 22.2.1.5 Template class codecvt
//
// Written by Benjamin Kosnik <bkoz@redhat.com>
/** @file ext/codecvt_specializations.h
* This file is a GNU extension to the Standard C++ Library.
*/
#ifndef _EXT_CODECVT_SPECIALIZATIONS_H
#define _EXT_CODECVT_SPECIALIZATIONS_H 1
#include <bits/c++config.h>
#include <locale>
#include <iconv.h>
namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
_GLIBCXX_BEGIN_NAMESPACE_CXX11
/// Extension to use iconv for dealing with character encodings.
// This includes conversions and comparisons between various character
// sets. This object encapsulates data that may need to be shared between
// char_traits, codecvt and ctype.
class encoding_state
{
public:
// Types:
// NB: A conversion descriptor subsumes and enhances the
// functionality of a simple state type such as mbstate_t.
typedef iconv_t descriptor_type;
protected:
// Name of internal character set encoding.
std::string _M_int_enc;
// Name of external character set encoding.
std::string _M_ext_enc;
// Conversion descriptor between external encoding to internal encoding.
descriptor_type _M_in_desc;
// Conversion descriptor between internal encoding to external encoding.
descriptor_type _M_out_desc;
// The byte-order marker for the external encoding, if necessary.
int _M_ext_bom;
// The byte-order marker for the internal encoding, if necessary.
int _M_int_bom;
// Number of external bytes needed to construct one complete
// character in the internal encoding.
// NB: -1 indicates variable, or stateful, encodings.
int _M_bytes;
public:
explicit
encoding_state()
: _M_in_desc(0), _M_out_desc(0), _M_ext_bom(0), _M_int_bom(0), _M_bytes(0)
{ }
explicit
encoding_state(const char* __int, const char* __ext,
int __ibom = 0, int __ebom = 0, int __bytes = 1)
: _M_int_enc(__int), _M_ext_enc(__ext), _M_in_desc(0), _M_out_desc(0),
_M_ext_bom(__ebom), _M_int_bom(__ibom), _M_bytes(__bytes)
{ init(); }
// 21.1.2 traits typedefs
// p4
// typedef STATE_T state_type
// requires: state_type shall meet the requirements of
// CopyConstructible types (20.1.3)
// NB: This does not preserve the actual state of the conversion
// descriptor member, but it does duplicate the encoding
// information.
encoding_state(const encoding_state& __obj) : _M_in_desc(0), _M_out_desc(0)
{ construct(__obj); }
// Need assignment operator as well.
encoding_state&
operator=(const encoding_state& __obj)
{
construct(__obj);
return *this;
}
~encoding_state()
{ destroy(); }
bool
good() const throw()
{
const descriptor_type __err = (iconv_t)(-1);
bool __test = _M_in_desc && _M_in_desc != __err;
__test &= _M_out_desc && _M_out_desc != __err;
return __test;
}
int
character_ratio() const
{ return _M_bytes; }
const std::string
internal_encoding() const
{ return _M_int_enc; }
int
internal_bom() const
{ return _M_int_bom; }
const std::string
external_encoding() const
{ return _M_ext_enc; }
int
external_bom() const
{ return _M_ext_bom; }
const descriptor_type&
in_descriptor() const
{ return _M_in_desc; }
const descriptor_type&
out_descriptor() const
{ return _M_out_desc; }
protected:
void
init()
{
const descriptor_type __err = (iconv_t)(-1);
const bool __have_encodings = _M_int_enc.size() && _M_ext_enc.size();
if (!_M_in_desc && __have_encodings)
{
_M_in_desc = iconv_open(_M_int_enc.c_str(), _M_ext_enc.c_str());
if (_M_in_desc == __err)
std::__throw_runtime_error(__N("encoding_state::_M_init "
"creating iconv input descriptor failed"));
}
if (!_M_out_desc && __have_encodings)
{
_M_out_desc = iconv_open(_M_ext_enc.c_str(), _M_int_enc.c_str());
if (_M_out_desc == __err)
std::__throw_runtime_error(__N("encoding_state::_M_init "
"creating iconv output descriptor failed"));
}
}
void
construct(const encoding_state& __obj)
{
destroy();
_M_int_enc = __obj._M_int_enc;
_M_ext_enc = __obj._M_ext_enc;
_M_ext_bom = __obj._M_ext_bom;
_M_int_bom = __obj._M_int_bom;
_M_bytes = __obj._M_bytes;
init();
}
void
destroy() throw()
{
const descriptor_type __err = (iconv_t)(-1);
if (_M_in_desc && _M_in_desc != __err)
{
iconv_close(_M_in_desc);
_M_in_desc = 0;
}
if (_M_out_desc && _M_out_desc != __err)
{
iconv_close(_M_out_desc);
_M_out_desc = 0;
}
}
};
/// encoding_char_traits
// Custom traits type with encoding_state for the state type, and the
// associated fpos<encoding_state> for the position type, all other
// bits equivalent to the required char_traits instantiations.
template<typename _CharT>
struct encoding_char_traits
: public std::char_traits<_CharT>
{
typedef encoding_state state_type;
typedef typename std::fpos<state_type> pos_type;
};
_GLIBCXX_END_NAMESPACE_CXX11
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
using __gnu_cxx::encoding_state;
/// codecvt<InternT, _ExternT, encoding_state> specialization.
// This partial specialization takes advantage of iconv to provide
// code conversions between a large number of character encodings.
template<typename _InternT, typename _ExternT>
class codecvt<_InternT, _ExternT, encoding_state>
: public __codecvt_abstract_base<_InternT, _ExternT, encoding_state>
{
public:
// Types:
typedef codecvt_base::result result;
typedef _InternT intern_type;
typedef _ExternT extern_type;
typedef __gnu_cxx::encoding_state state_type;
typedef state_type::descriptor_type descriptor_type;
// Data Members:
static locale::id id;
explicit
codecvt(size_t __refs = 0)
: __codecvt_abstract_base<intern_type, extern_type, state_type>(__refs)
{ }
explicit
codecvt(state_type& __enc, size_t __refs = 0)
: __codecvt_abstract_base<intern_type, extern_type, state_type>(__refs)
{ }
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>
locale::id
codecvt<_InternT, _ExternT, encoding_state>::id;
// This adaptor works around the signature problems of the second
// argument to iconv(): SUSv2 and others use 'const char**', but glibc 2.2
// uses 'char**', which matches the POSIX 1003.1-2001 standard.
// Using this adaptor, g++ will do the work for us.
template<typename _Tp>
inline size_t
__iconv_adaptor(size_t(*__func)(iconv_t, _Tp, size_t*, char**, size_t*),
iconv_t __cd, char** __inbuf, size_t* __inbytes,
char** __outbuf, size_t* __outbytes)
{ return __func(__cd, (_Tp)__inbuf, __inbytes, __outbuf, __outbytes); }
template<typename _InternT, typename _ExternT>
codecvt_base::result
codecvt<_InternT, _ExternT, encoding_state>::
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
{
result __ret = codecvt_base::error;
if (__state.good())
{
const descriptor_type& __desc = __state.out_descriptor();
const size_t __fmultiple = sizeof(intern_type);
size_t __fbytes = __fmultiple * (__from_end - __from);
const size_t __tmultiple = sizeof(extern_type);
size_t __tbytes = __tmultiple * (__to_end - __to);
// Argument list for iconv specifies a byte sequence. Thus,
// all to/from arrays must be brutally casted to char*.
char* __cto = reinterpret_cast<char*>(__to);
char* __cfrom;
size_t __conv;
// Some encodings need a byte order marker as the first item
// in the byte stream, to designate endian-ness. The default
// value for the byte order marker is NULL, so if this is
// the case, it's not necessary and we can just go on our
// merry way.
int __int_bom = __state.internal_bom();
if (__int_bom)
{
size_t __size = __from_end - __from;
intern_type* __cfixed = static_cast<intern_type*>
(__builtin_alloca(sizeof(intern_type) * (__size + 1)));
__cfixed[0] = static_cast<intern_type>(__int_bom);
char_traits<intern_type>::copy(__cfixed + 1, __from, __size);
__cfrom = reinterpret_cast<char*>(__cfixed);
__conv = __iconv_adaptor(iconv, __desc, &__cfrom,
&__fbytes, &__cto, &__tbytes);
}
else
{
intern_type* __cfixed = const_cast<intern_type*>(__from);
__cfrom = reinterpret_cast<char*>(__cfixed);
__conv = __iconv_adaptor(iconv, __desc, &__cfrom, &__fbytes,
&__cto, &__tbytes);
}
if (__conv != size_t(-1))
{
__from_next = reinterpret_cast<const intern_type*>(__cfrom);
__to_next = reinterpret_cast<extern_type*>(__cto);
__ret = codecvt_base::ok;
}
else
{
if (__fbytes < __fmultiple * (__from_end - __from))
{
__from_next = reinterpret_cast<const intern_type*>(__cfrom);
__to_next = reinterpret_cast<extern_type*>(__cto);
__ret = codecvt_base::partial;
}
else
__ret = codecvt_base::error;
}
}
return __ret;
}
template<typename _InternT, typename _ExternT>
codecvt_base::result
codecvt<_InternT, _ExternT, encoding_state>::
do_unshift(state_type& __state, extern_type* __to,
extern_type* __to_end, extern_type*& __to_next) const
{
result __ret = codecvt_base::error;
if (__state.good())
{
const descriptor_type& __desc = __state.in_descriptor();
const size_t __tmultiple = sizeof(intern_type);
size_t __tlen = __tmultiple * (__to_end - __to);
// Argument list for iconv specifies a byte sequence. Thus,
// all to/from arrays must be brutally casted to char*.
char* __cto = reinterpret_cast<char*>(__to);
size_t __conv = __iconv_adaptor(iconv,__desc, 0, 0,
&__cto, &__tlen);
if (__conv != size_t(-1))
{
__to_next = reinterpret_cast<extern_type*>(__cto);
if (__tlen == __tmultiple * (__to_end - __to))
__ret = codecvt_base::noconv;
else if (__tlen == 0)
__ret = codecvt_base::ok;
else
__ret = codecvt_base::partial;
}
else
__ret = codecvt_base::error;
}
return __ret;
}
template<typename _InternT, typename _ExternT>
codecvt_base::result
codecvt<_InternT, _ExternT, encoding_state>::
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
{
result __ret = codecvt_base::error;
if (__state.good())
{
const descriptor_type& __desc = __state.in_descriptor();
const size_t __fmultiple = sizeof(extern_type);
size_t __flen = __fmultiple * (__from_end - __from);
const size_t __tmultiple = sizeof(intern_type);
size_t __tlen = __tmultiple * (__to_end - __to);
// Argument list for iconv specifies a byte sequence. Thus,
// all to/from arrays must be brutally casted to char*.
char* __cto = reinterpret_cast<char*>(__to);
char* __cfrom;
size_t __conv;
// Some encodings need a byte order marker as the first item
// in the byte stream, to designate endian-ness. The default
// value for the byte order marker is NULL, so if this is
// the case, it's not necessary and we can just go on our
// merry way.
int __ext_bom = __state.external_bom();
if (__ext_bom)
{
size_t __size = __from_end - __from;
extern_type* __cfixed = static_cast<extern_type*>
(__builtin_alloca(sizeof(extern_type) * (__size + 1)));
__cfixed[0] = static_cast<extern_type>(__ext_bom);
char_traits<extern_type>::copy(__cfixed + 1, __from, __size);
__cfrom = reinterpret_cast<char*>(__cfixed);
__conv = __iconv_adaptor(iconv, __desc, &__cfrom,
&__flen, &__cto, &__tlen);
}
else
{
extern_type* __cfixed = const_cast<extern_type*>(__from);
__cfrom = reinterpret_cast<char*>(__cfixed);
__conv = __iconv_adaptor(iconv, __desc, &__cfrom,
&__flen, &__cto, &__tlen);
}
if (__conv != size_t(-1))
{
__from_next = reinterpret_cast<const extern_type*>(__cfrom);
__to_next = reinterpret_cast<intern_type*>(__cto);
__ret = codecvt_base::ok;
}
else
{
if (__flen < static_cast<size_t>(__from_end - __from))
{
__from_next = reinterpret_cast<const extern_type*>(__cfrom);
__to_next = reinterpret_cast<intern_type*>(__cto);
__ret = codecvt_base::partial;
}
else
__ret = codecvt_base::error;
}
}
return __ret;
}
template<typename _InternT, typename _ExternT>
int
codecvt<_InternT, _ExternT, encoding_state>::
do_encoding() const throw()
{
int __ret = 0;
if (sizeof(_ExternT) <= sizeof(_InternT))
__ret = sizeof(_InternT) / sizeof(_ExternT);
return __ret;
}
template<typename _InternT, typename _ExternT>
bool
codecvt<_InternT, _ExternT, encoding_state>::
do_always_noconv() const throw()
{ return false; }
template<typename _InternT, typename _ExternT>
int
codecvt<_InternT, _ExternT, encoding_state>::
do_length(state_type&, const extern_type* __from,
const extern_type* __end, size_t __max) const
{ return std::min(__max, static_cast<size_t>(__end - __from)); }
// _GLIBCXX_RESOLVE_LIB_DEFECTS
// 74. Garbled text for codecvt::do_max_length
template<typename _InternT, typename _ExternT>
int
codecvt<_InternT, _ExternT, encoding_state>::
do_max_length() const throw()
{ return 1; }
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace
#endif
locale
c++config.h
std::min
constexpr const _Tp & min(const _Tp &, const _Tp &)
This does what you think it does.
Definition: stl_algobase.h:230
std
ISO C++ entities toplevel namespace is std.
__gnu_cxx
GNU extensions for public use.
std::basic_string< char >
std::basic_string::c_str
const _CharT * c_str() const noexcept
Return const pointer to null-terminated contents.
Definition: basic_string.h:5256
std::basic_string::size
size_type size() const noexcept
Returns the number of characters in the string, not including any null-termination.
Definition: basic_string.h:3963
std::char_traits
Basis for explicit traits specializations.
Definition: char_traits.h:339
std::__codecvt_abstract_base
Common base for codecvt functions.
Definition: codecvt.h:73
std::codecvt
Primary class template codecvt.
Definition: codecvt.h:279
std::codecvt::do_out
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
Convert from internal to external character set.
std::locale::id
Facet ID class.
Definition: locale_classes.h:486
std::fpos
Class representing stream positions.
Definition: postypes.h:113
__gnu_cxx::encoding_state
Extension to use iconv for dealing with character encodings.
Definition: codecvt_specializations.h:52
__gnu_cxx::encoding_char_traits
encoding_char_traits
Definition: codecvt_specializations.h:213