Edit File: char_traits.h
// Character Traits for use by standard string and iostream -*- C++ -*- // Copyright (C) 1997-2018 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/char_traits.h * This is an internal header file, included by other library headers. * Do not attempt to use it directly. @headername{string} */ // // ISO C++ 14882: 21 Strings library // #ifndef _CHAR_TRAITS_H #define _CHAR_TRAITS_H 1 #pragma GCC system_header #include <bits/stl_algobase.h> // std::copy, std::fill_n #include <bits/postypes.h> // For streampos #include <cwchar> // For WEOF, wmemmove, wmemset, etc. #ifndef _GLIBCXX_ALWAYS_INLINE #define _GLIBCXX_ALWAYS_INLINE inline __attribute__((__always_inline__)) #endif namespace __gnu_cxx _GLIBCXX_VISIBILITY(default) { _GLIBCXX_BEGIN_NAMESPACE_VERSION /** * @brief Mapping from character type to associated types. * * @note This is an implementation class for the generic version * of char_traits. It defines int_type, off_type, pos_type, and * state_type. By default these are unsigned long, streamoff, * streampos, and mbstate_t. Users who need a different set of * types, but who don't need to change the definitions of any function * defined in char_traits, can specialize __gnu_cxx::_Char_types * while leaving __gnu_cxx::char_traits alone. */ template<typename _CharT> struct _Char_types { typedef unsigned long int_type; typedef std::streampos pos_type; typedef std::streamoff off_type; typedef std::mbstate_t state_type; }; /** * @brief Base class used to implement std::char_traits. * * @note For any given actual character type, this definition is * probably wrong. (Most of the member functions are likely to be * right, but the int_type and state_type typedefs, and the eof() * member function, are likely to be wrong.) The reason this class * exists is so users can specialize it. Classes in namespace std * may not be specialized for fundamental types, but classes in * namespace __gnu_cxx may be. * * See https://gcc.gnu.org/onlinedocs/libstdc++/manual/strings.html#strings.string.character_types * for advice on how to make use of this class for @a unusual character * types. Also, check out include/ext/pod_char_traits.h. */ template<typename _CharT> struct char_traits { typedef _CharT char_type; typedef typename _Char_types<_CharT>::int_type int_type; typedef typename _Char_types<_CharT>::pos_type pos_type; typedef typename _Char_types<_CharT>::off_type off_type; typedef typename _Char_types<_CharT>::state_type state_type; static _GLIBCXX14_CONSTEXPR void assign(char_type& __c1, const char_type& __c2) { __c1 = __c2; } static _GLIBCXX_CONSTEXPR bool eq(const char_type& __c1, const char_type& __c2) { return __c1 == __c2; } static _GLIBCXX_CONSTEXPR bool lt(const char_type& __c1, const char_type& __c2) { return __c1 < __c2; } static _GLIBCXX14_CONSTEXPR int compare(const char_type* __s1, const char_type* __s2, std::size_t __n); static _GLIBCXX14_CONSTEXPR std::size_t length(const char_type* __s); static _GLIBCXX14_CONSTEXPR const char_type* find(const char_type* __s, std::size_t __n, const char_type& __a); static char_type* move(char_type* __s1, const char_type* __s2, std::size_t __n); static char_type* copy(char_type* __s1, const char_type* __s2, std::size_t __n); static char_type* assign(char_type* __s, std::size_t __n, char_type __a); static _GLIBCXX_CONSTEXPR char_type to_char_type(const int_type& __c) { return static_cast<char_type>(__c); } static _GLIBCXX_CONSTEXPR int_type to_int_type(const char_type& __c) { return static_cast<int_type>(__c); } static _GLIBCXX_CONSTEXPR bool eq_int_type(const int_type& __c1, const int_type& __c2) { return __c1 == __c2; } static _GLIBCXX_CONSTEXPR int_type eof() { return static_cast<int_type>(_GLIBCXX_STDIO_EOF); } static _GLIBCXX_CONSTEXPR int_type not_eof(const int_type& __c) { return !eq_int_type(__c, eof()) ? __c : to_int_type(char_type()); } }; template<typename _CharT> _GLIBCXX14_CONSTEXPR int char_traits<_CharT>:: compare(const char_type* __s1, const char_type* __s2, std::size_t __n) { for (std::size_t __i = 0; __i < __n; ++__i) if (lt(__s1[__i], __s2[__i])) return -1; else if (lt(__s2[__i], __s1[__i])) return 1; return 0; } template<typename _CharT> _GLIBCXX14_CONSTEXPR std::size_t char_traits<_CharT>:: length(const char_type* __p) { std::size_t __i = 0; while (!eq(__p[__i], char_type())) ++__i; return __i; } template<typename _CharT> _GLIBCXX14_CONSTEXPR const typename char_traits<_CharT>::char_type* char_traits<_CharT>:: find(const char_type* __s, std::size_t __n, const char_type& __a) { for (std::size_t __i = 0; __i < __n; ++__i) if (eq(__s[__i], __a)) return __s + __i; return 0; } template<typename _CharT> typename char_traits<_CharT>::char_type* char_traits<_CharT>:: move(char_type* __s1, const char_type* __s2, std::size_t __n) { if (__n == 0) return __s1; return static_cast<_CharT*>(__builtin_memmove(__s1, __s2, __n * sizeof(char_type))); } template<typename _CharT> typename char_traits<_CharT>::char_type* char_traits<_CharT>:: copy(char_type* __s1, const char_type* __s2, std::size_t __n) { // NB: Inline std::copy so no recursive dependencies. std::copy(__s2, __s2 + __n, __s1); return __s1; } template<typename _CharT> typename char_traits<_CharT>::char_type* char_traits<_CharT>:: assign(char_type* __s, std::size_t __n, char_type __a) { // NB: Inline std::fill_n so no recursive dependencies. std::fill_n(__s, __n, __a); return __s; } _GLIBCXX_END_NAMESPACE_VERSION } // namespace namespace std _GLIBCXX_VISIBILITY(default) { _GLIBCXX_BEGIN_NAMESPACE_VERSION #if __cplusplus > 201402 #define __cpp_lib_constexpr_char_traits 201611 /** * @brief Determine whether the characters of a NULL-terminated * string are known at compile time. * @param __s The string. * * Assumes that _CharT is a built-in character type. */ template<typename _CharT> static _GLIBCXX_ALWAYS_INLINE constexpr bool __constant_string_p(const _CharT* __s) { while (__builtin_constant_p(*__s) && *__s) __s++; return __builtin_constant_p(*__s); } /** * @brief Determine whether the characters of a character array are * known at compile time. * @param __a The character array. * @param __n Number of characters. * * Assumes that _CharT is a built-in character type. */ template<typename _CharT> static _GLIBCXX_ALWAYS_INLINE constexpr bool __constant_char_array_p(const _CharT* __a, size_t __n) { size_t __i = 0; while (__i < __n && __builtin_constant_p(__a[__i])) __i++; return __i == __n; } #endif // 21.1 /** * @brief Basis for explicit traits specializations. * * @note For any given actual character type, this definition is * probably wrong. Since this is just a thin wrapper around * __gnu_cxx::char_traits, it is possible to achieve a more * appropriate definition by specializing __gnu_cxx::char_traits. * * See https://gcc.gnu.org/onlinedocs/libstdc++/manual/strings.html#strings.string.character_types * for advice on how to make use of this class for @a unusual character * types. Also, check out include/ext/pod_char_traits.h. */ template<class _CharT> struct char_traits : public __gnu_cxx::char_traits<_CharT> { }; /// 21.1.3.1 char_traits specializations template<> struct char_traits<char> { typedef char char_type; typedef int int_type; typedef streampos pos_type; typedef streamoff off_type; typedef mbstate_t state_type; static _GLIBCXX17_CONSTEXPR void assign(char_type& __c1, const char_type& __c2) _GLIBCXX_NOEXCEPT { __c1 = __c2; } static _GLIBCXX_CONSTEXPR bool eq(const char_type& __c1, const char_type& __c2) _GLIBCXX_NOEXCEPT { return __c1 == __c2; } static _GLIBCXX_CONSTEXPR bool lt(const char_type& __c1, const char_type& __c2) _GLIBCXX_NOEXCEPT { // LWG 467. return (static_cast<unsigned char>(__c1) < static_cast<unsigned char>(__c2)); } static _GLIBCXX17_CONSTEXPR int compare(const char_type* __s1, const char_type* __s2, size_t __n) { #if __cplusplus > 201402 if (__builtin_constant_p(__n) && __constant_char_array_p(__s1, __n) && __constant_char_array_p(__s2, __n)) { for (size_t __i = 0; __i < __n; ++__i) if (lt(__s1[__i], __s2[__i])) return -1; else if (lt(__s2[__i], __s1[__i])) return 1; return 0; } #endif if (__n == 0) return 0; return __builtin_memcmp(__s1, __s2, __n); } static _GLIBCXX17_CONSTEXPR size_t length(const char_type* __s) { #if __cplusplus > 201402 if (__constant_string_p(__s)) return __gnu_cxx::char_traits<char_type>::length(__s); #endif return __builtin_strlen(__s); } static _GLIBCXX17_CONSTEXPR const char_type* find(const char_type* __s, size_t __n, const char_type& __a) { #if __cplusplus > 201402 if (__builtin_constant_p(__n) && __builtin_constant_p(__a) && __constant_char_array_p(__s, __n)) return __gnu_cxx::char_traits<char_type>::find(__s, __n, __a); #endif if (__n == 0) return 0; return static_cast<const char_type*>(__builtin_memchr(__s, __a, __n)); } static char_type* move(char_type* __s1, const char_type* __s2, size_t __n) { if (__n == 0) return __s1; return static_cast<char_type*>(__builtin_memmove(__s1, __s2, __n)); } static char_type* copy(char_type* __s1, const char_type* __s2, size_t __n) { if (__n == 0) return __s1; return static_cast<char_type*>(__builtin_memcpy(__s1, __s2, __n)); } static char_type* assign(char_type* __s, size_t __n, char_type __a) { if (__n == 0) return __s; return static_cast<char_type*>(__builtin_memset(__s, __a, __n)); } static _GLIBCXX_CONSTEXPR char_type to_char_type(const int_type& __c) _GLIBCXX_NOEXCEPT { return static_cast<char_type>(__c); } // To keep both the byte 0xff and the eof symbol 0xffffffff // from ending up as 0xffffffff. static _GLIBCXX_CONSTEXPR int_type to_int_type(const char_type& __c) _GLIBCXX_NOEXCEPT { return static_cast<int_type>(static_cast<unsigned char>(__c)); } static _GLIBCXX_CONSTEXPR bool eq_int_type(const int_type& __c1, const int_type& __c2) _GLIBCXX_NOEXCEPT { return __c1 == __c2; } static _GLIBCXX_CONSTEXPR int_type eof() _GLIBCXX_NOEXCEPT { return static_cast<int_type>(_GLIBCXX_STDIO_EOF); } static _GLIBCXX_CONSTEXPR int_type not_eof(const int_type& __c) _GLIBCXX_NOEXCEPT { return (__c == eof()) ? 0 : __c; } }; #ifdef _GLIBCXX_USE_WCHAR_T /// 21.1.3.2 char_traits specializations template<> struct char_traits<wchar_t> { typedef wchar_t char_type; typedef wint_t int_type; typedef streamoff off_type; typedef wstreampos pos_type; typedef mbstate_t state_type; static _GLIBCXX17_CONSTEXPR void assign(char_type& __c1, const char_type& __c2) _GLIBCXX_NOEXCEPT { __c1 = __c2; } static _GLIBCXX_CONSTEXPR bool eq(const char_type& __c1, const char_type& __c2) _GLIBCXX_NOEXCEPT { return __c1 == __c2; } static _GLIBCXX_CONSTEXPR bool lt(const char_type& __c1, const char_type& __c2) _GLIBCXX_NOEXCEPT { return __c1 < __c2; } static _GLIBCXX17_CONSTEXPR int compare(const char_type* __s1, const char_type* __s2, size_t __n) { #if __cplusplus > 201402 if (__builtin_constant_p(__n) && __constant_char_array_p(__s1, __n) && __constant_char_array_p(__s2, __n)) return __gnu_cxx::char_traits<char_type>::compare(__s1, __s2, __n); #endif if (__n == 0) return 0; else return wmemcmp(__s1, __s2, __n); } static _GLIBCXX17_CONSTEXPR size_t length(const char_type* __s) { #if __cplusplus > 201402 if (__constant_string_p(__s)) return __gnu_cxx::char_traits<char_type>::length(__s); else #endif return wcslen(__s); } static _GLIBCXX17_CONSTEXPR const char_type* find(const char_type* __s, size_t __n, const char_type& __a) { #if __cplusplus > 201402 if (__builtin_constant_p(__n) && __builtin_constant_p(__a) && __constant_char_array_p(__s, __n)) return __gnu_cxx::char_traits<char_type>::find(__s, __n, __a); #endif if (__n == 0) return 0; else return wmemchr(__s, __a, __n); } static char_type* move(char_type* __s1, const char_type* __s2, size_t __n) { if (__n == 0) return __s1; return wmemmove(__s1, __s2, __n); } static char_type* copy(char_type* __s1, const char_type* __s2, size_t __n) { if (__n == 0) return __s1; return wmemcpy(__s1, __s2, __n); } static char_type* assign(char_type* __s, size_t __n, char_type __a) { if (__n == 0) return __s; return wmemset(__s, __a, __n); } static _GLIBCXX_CONSTEXPR char_type to_char_type(const int_type& __c) _GLIBCXX_NOEXCEPT { return char_type(__c); } static _GLIBCXX_CONSTEXPR int_type to_int_type(const char_type& __c) _GLIBCXX_NOEXCEPT { return int_type(__c); } static _GLIBCXX_CONSTEXPR bool eq_int_type(const int_type& __c1, const int_type& __c2) _GLIBCXX_NOEXCEPT { return __c1 == __c2; } static _GLIBCXX_CONSTEXPR int_type eof() _GLIBCXX_NOEXCEPT { return static_cast<int_type>(WEOF); } static _GLIBCXX_CONSTEXPR int_type not_eof(const int_type& __c) _GLIBCXX_NOEXCEPT { return eq_int_type(__c, eof()) ? 0 : __c; } }; #endif //_GLIBCXX_USE_WCHAR_T _GLIBCXX_END_NAMESPACE_VERSION } // namespace #if ((__cplusplus >= 201103L) \ && defined(_GLIBCXX_USE_C99_STDINT_TR1)) #include <cstdint> namespace std _GLIBCXX_VISIBILITY(default) { _GLIBCXX_BEGIN_NAMESPACE_VERSION template<> struct char_traits<char16_t> { typedef char16_t char_type; typedef uint_least16_t int_type; typedef streamoff off_type; typedef u16streampos pos_type; typedef mbstate_t state_type; static _GLIBCXX17_CONSTEXPR void assign(char_type& __c1, const char_type& __c2) noexcept { __c1 = __c2; } static constexpr bool eq(const char_type& __c1, const char_type& __c2) noexcept { return __c1 == __c2; } static constexpr bool lt(const char_type& __c1, const char_type& __c2) noexcept { return __c1 < __c2; } static _GLIBCXX17_CONSTEXPR int compare(const char_type* __s1, const char_type* __s2, size_t __n) { for (size_t __i = 0; __i < __n; ++__i) if (lt(__s1[__i], __s2[__i])) return -1; else if (lt(__s2[__i], __s1[__i])) return 1; return 0; } static _GLIBCXX17_CONSTEXPR size_t length(const char_type* __s) { size_t __i = 0; while (!eq(__s[__i], char_type())) ++__i; return __i; } static _GLIBCXX17_CONSTEXPR const char_type* find(const char_type* __s, size_t __n, const char_type& __a) { for (size_t __i = 0; __i < __n; ++__i) if (eq(__s[__i], __a)) return __s + __i; return 0; } static char_type* move(char_type* __s1, const char_type* __s2, size_t __n) { if (__n == 0) return __s1; return (static_cast<char_type*> (__builtin_memmove(__s1, __s2, __n * sizeof(char_type)))); } static char_type* copy(char_type* __s1, const char_type* __s2, size_t __n) { if (__n == 0) return __s1; return (static_cast<char_type*> (__builtin_memcpy(__s1, __s2, __n * sizeof(char_type)))); } static char_type* assign(char_type* __s, size_t __n, char_type __a) { for (size_t __i = 0; __i < __n; ++__i) assign(__s[__i], __a); return __s; } static constexpr char_type to_char_type(const int_type& __c) noexcept { return char_type(__c); } static constexpr int_type to_int_type(const char_type& __c) noexcept { return __c == eof() ? int_type(0xfffd) : int_type(__c); } static constexpr bool eq_int_type(const int_type& __c1, const int_type& __c2) noexcept { return __c1 == __c2; } static constexpr int_type eof() noexcept { return static_cast<int_type>(-1); } static constexpr int_type not_eof(const int_type& __c) noexcept { return eq_int_type(__c, eof()) ? 0 : __c; } }; template<> struct char_traits<char32_t> { typedef char32_t char_type; typedef uint_least32_t int_type; typedef streamoff off_type; typedef u32streampos pos_type; typedef mbstate_t state_type; static _GLIBCXX17_CONSTEXPR void assign(char_type& __c1, const char_type& __c2) noexcept { __c1 = __c2; } static constexpr bool eq(const char_type& __c1, const char_type& __c2) noexcept { return __c1 == __c2; } static constexpr bool lt(const char_type& __c1, const char_type& __c2) noexcept { return __c1 < __c2; } static _GLIBCXX17_CONSTEXPR int compare(const char_type* __s1, const char_type* __s2, size_t __n) { for (size_t __i = 0; __i < __n; ++__i) if (lt(__s1[__i], __s2[__i])) return -1; else if (lt(__s2[__i], __s1[__i])) return 1; return 0; } static _GLIBCXX17_CONSTEXPR size_t length(const char_type* __s) { size_t __i = 0; while (!eq(__s[__i], char_type())) ++__i; return __i; } static _GLIBCXX17_CONSTEXPR const char_type* find(const char_type* __s, size_t __n, const char_type& __a) { for (size_t __i = 0; __i < __n; ++__i) if (eq(__s[__i], __a)) return __s + __i; return 0; } static char_type* move(char_type* __s1, const char_type* __s2, size_t __n) { if (__n == 0) return __s1; return (static_cast<char_type*> (__builtin_memmove(__s1, __s2, __n * sizeof(char_type)))); } static char_type* copy(char_type* __s1, const char_type* __s2, size_t __n) { if (__n == 0) return __s1; return (static_cast<char_type*> (__builtin_memcpy(__s1, __s2, __n * sizeof(char_type)))); } static char_type* assign(char_type* __s, size_t __n, char_type __a) { for (size_t __i = 0; __i < __n; ++__i) assign(__s[__i], __a); return __s; } static constexpr char_type to_char_type(const int_type& __c) noexcept { return char_type(__c); } static constexpr int_type to_int_type(const char_type& __c) noexcept { return int_type(__c); } static constexpr bool eq_int_type(const int_type& __c1, const int_type& __c2) noexcept { return __c1 == __c2; } static constexpr int_type eof() noexcept { return static_cast<int_type>(-1); } static constexpr int_type not_eof(const int_type& __c) noexcept { return eq_int_type(__c, eof()) ? 0 : __c; } }; _GLIBCXX_END_NAMESPACE_VERSION } // namespace #endif #endif // _CHAR_TRAITS_H
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