类模板 std::codecvt 封装字符串的转换，包括宽和多字节，从一种编码到另一种。通过 std::basic_fstream<CharT> 进行的所有输入/输出操作都使用流中浸染的 std::codecvt<CharT, char, std::mbstate_t> 本地环境刻面。
// <codecvt> -*- C++ -*-
// Copyright (C) 2015-2020 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: 22.5 Standard code conversion facets
/** @file include/codecvt
* This is a Standard C++ Library header.
*/
#ifndef _GLIBCXX_CODECVT
#define _GLIBCXX_CODECVT 1
#pragma GCC system_header
#if __cplusplus < 201103L
# include <bits/c++0x_warning.h>
#else
#include <bits/locale_classes.h>
#include <bits/codecvt.h>
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
enum codecvt_mode
{
consume_header = 4,
generate_header = 2,
little_endian = 1
};
template<typename _Elem, unsigned long _Maxcode = 0x10ffff,
codecvt_mode _Mode = (codecvt_mode)0>
class codecvt_utf8 : public codecvt<_Elem, char, mbstate_t>
{
public:
explicit
codecvt_utf8(size_t __refs = 0);
~codecvt_utf8();
};
template<typename _Elem, unsigned long _Maxcode = 0x10ffff,
codecvt_mode _Mode = (codecvt_mode)0>
class codecvt_utf16 : public codecvt<_Elem, char, mbstate_t>
{
public:
explicit
codecvt_utf16(size_t __refs = 0);
~codecvt_utf16();
};
template<typename _Elem, unsigned long _Maxcode = 0x10ffff,
codecvt_mode _Mode = (codecvt_mode)0>
class codecvt_utf8_utf16 : public codecvt<_Elem, char, mbstate_t>
{
public:
explicit
codecvt_utf8_utf16(size_t __refs = 0);
~codecvt_utf8_utf16();
};
#define _GLIBCXX_CODECVT_SPECIALIZATION2(_NAME, _ELEM) \
template<> \
class _NAME<_ELEM> \
: public codecvt<_ELEM, char, mbstate_t> \
{ \
public: \
typedef _ELEM intern_type; \
typedef char extern_type; \
typedef mbstate_t state_type; \
\
protected: \
_NAME(unsigned long __maxcode, codecvt_mode __mode, size_t __refs) \
: codecvt(__refs), _M_maxcode(__maxcode), _M_mode(__mode) { } \
\
virtual \
~_NAME(); \
\
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(); \
\
private: \
unsigned long _M_maxcode; \
codecvt_mode _M_mode; \
}
#define _GLIBCXX_CODECVT_SPECIALIZATION(_NAME, _ELEM) \
_GLIBCXX_CODECVT_SPECIALIZATION2(__ ## _NAME ## _base, _ELEM); \
template<unsigned long _Maxcode, codecvt_mode _Mode> \
class _NAME<_ELEM, _Maxcode, _Mode> \
: public __ ## _NAME ## _base<_ELEM> \
{ \
public: \
explicit \
_NAME(size_t __refs = 0) \
: __ ## _NAME ## _base<_ELEM>(std::min(_Maxcode, 0x10fffful), \
_Mode, __refs) \
{ } \
}
template<typename _Elem> class __codecvt_utf8_base;
template<typename _Elem> class __codecvt_utf16_base;
template<typename _Elem> class __codecvt_utf8_utf16_base;
_GLIBCXX_CODECVT_SPECIALIZATION(codecvt_utf8, char16_t);
_GLIBCXX_CODECVT_SPECIALIZATION(codecvt_utf16, char16_t);
_GLIBCXX_CODECVT_SPECIALIZATION(codecvt_utf8_utf16, char16_t);
_GLIBCXX_CODECVT_SPECIALIZATION(codecvt_utf8, char32_t);
_GLIBCXX_CODECVT_SPECIALIZATION(codecvt_utf16, char32_t);
_GLIBCXX_CODECVT_SPECIALIZATION(codecvt_utf8_utf16, char32_t);
#ifdef _GLIBCXX_USE_WCHAR_T
_GLIBCXX_CODECVT_SPECIALIZATION(codecvt_utf8, wchar_t);
_GLIBCXX_CODECVT_SPECIALIZATION(codecvt_utf16, wchar_t);
_GLIBCXX_CODECVT_SPECIALIZATION(codecvt_utf8_utf16, wchar_t);
#endif
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace
#endif // C++11
#endif /* _GLIBCXX_CODECVT */成员函数
构造新的 codecvt 刻面(公开成员函数) | |
调用 do_out(公开成员函数) | |
调用 do_in(公开成员函数) | |
调用 do_unshift(公开成员函数) | |
调用 do_encoding(公开成员函数) | |
调用 do_always_noconv(公开成员函数) | |
调用 do_length(公开成员函数) | |
调用 do_max_length(公开成员函数) |
受保护成员函数
销毁 codecvt 刻面(受保护成员函数) | |
| [虚] | 将字符串从 InternT 转换到 ExternT，例如在写入文件时(虚受保护成员函数) |
| [虚] | 将字符串从 ExternT 转换到 InternT，例如在从文件读取时(虚受保护成员函数) |
| [虚] | 为不完整转换生成 ExternT 字符的终止字符序列(虚受保护成员函数) |
| [虚] | 返回产生一个 InternT 字符所需的 ExternT 字符数，如果它是常数(虚受保护成员函数) |
| [虚] | 测试刻面的编码是否对所有合法实参值都是恒等转换 (虚受保护成员函数) |
| [虚] | 计算转换成给定的 InternT 缓冲区会消耗的 ExternT 字符串长度(虚受保护成员函数) |
| [虚] | 返回能转换成单个 InternT 字符的最大 ExternT 字符数(虚受保护成员函数) |
继承自 std::codecvt_base
| 嵌套类型 | 定义 |
| enum result { ok, partial, error, noconv }; | 无作用域枚举类型 |
| 枚举常量 | 定义 |
ok | 完成转换而无错误 |
partial | 未转换所有源字符 |
error | 遇到非法字符 |
noconv | 无需转换，输入与输出类型相同 |
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