1 // Helper for accessing __cxx11::string from the ABI -*- C++ -*- 2 3 // Copyright (C) 2014-2019 Free Software Foundation, Inc. 4 // 5 // This file is part of the GNU ISO C++ Library. This library is free 6 // software; you can redistribute it and/or modify it under the 7 // terms of the GNU General Public License as published by the 8 // Free Software Foundation; either version 3, or (at your option) 9 // any later version. 10 11 // This library is distributed in the hope that it will be useful, 12 // but WITHOUT ANY WARRANTY; without even the implied warranty of 13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 // GNU General Public License for more details. 15 16 // Under Section 7 of GPL version 3, you are granted additional 17 // permissions described in the GCC Runtime Library Exception, version 18 // 3.1, as published by the Free Software Foundation. 19 20 // You should have received a copy of the GNU General Public License and 21 // a copy of the GCC Runtime Library Exception along with this program; 22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 23 // <http://www.gnu.org/licenses/>. 24 25 26 #define _GLIBCXX_USE_CXX11_ABI 1 27 #define __sso_string __sso_stringxxx 28 #include <string> 29 #include <stdexcept> 30 #undef __sso_string 31 32 #if ! _GLIBCXX_USE_DUAL_ABI 33 # error This file should not be compiled for this configuration. 34 #endif 35 36 namespace std _GLIBCXX_VISIBILITY(default) 37 { 38 _GLIBCXX_BEGIN_NAMESPACE_VERSION 39 40 #pragma GCC diagnostic push 41 #pragma GCC diagnostic ignored "-Wabi-tag" 42 // Redefine __sso_string so that we can define and export its members 43 // in terms of the SSO std::string. 44 struct __sso_string 45 { 46 struct __str 47 { 48 const char* _M_p; 49 size_t _M_string_length; 50 char _M_local_buf[16]; 51 }; 52 53 union { 54 __str _M_s; 55 char _M_bytes[sizeof(_M_s)]; 56 std::string _M_str; 57 }; 58 59 __sso_string(); 60 __sso_string(const std::string& s); 61 __sso_string(const char*, size_t n); 62 __sso_string(const __sso_string&) noexcept; 63 __sso_string& operator=(const __sso_string&) noexcept; 64 ~__sso_string(); 65 __sso_string(__sso_string&&) noexcept; 66 __sso_string& operator=(__sso_string&&) noexcept; 67 }; 68 #pragma GCC diagnostic pop 69 __sso_string()70 __sso_string::__sso_string() : _M_str() { } 71 72 #if _GLIBCXX_USE_CXX11_ABI 73 static_assert(sizeof(__sso_string) == sizeof(std::string), 74 "sizeof(std::string) has changed"); 75 static_assert(alignof(__sso_string) == alignof(std::string), 76 "alignof(std::string) has changed"); 77 78 // This constructor is defined in src/c++11/cow-stdexcept.cc for COW strings __sso_string(const std::string & s)79 __sso_string::__sso_string(const std::string& s) : _M_str(s) { } 80 #endif 81 __sso_string(const char * s,size_t n)82 __sso_string::__sso_string(const char* s, size_t n) : _M_str(s, n) { } 83 __sso_string(const __sso_string & s)84 __sso_string::__sso_string(const __sso_string& s) noexcept 85 : _M_str(s._M_str) { } 86 87 __sso_string& operator =(const __sso_string & s)88 __sso_string::operator=(const __sso_string& s) noexcept 89 { 90 _M_str = s._M_str; 91 return *this; 92 } 93 ~__sso_string()94 __sso_string::~__sso_string() { _M_str.~basic_string(); } 95 __sso_string(__sso_string && s)96 __sso_string::__sso_string(__sso_string&& s) noexcept 97 : _M_str(std::move(s._M_str)) { } 98 99 __sso_string& operator =(__sso_string && s)100 __sso_string::operator=(__sso_string&& s) noexcept 101 { 102 _M_str = std::move(s._M_str); 103 return *this; 104 } 105 106 _GLIBCXX_END_NAMESPACE_VERSION 107 } // namespace 108