1 // <syncstream> -*- C++ -*-
3 // Copyright (C) 2020-2024 Free Software Foundation, Inc.
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)
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.
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.
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/>.
25 /** @file include/syncstream
26 * This is a Standard C++ Library header.
29 #ifndef _GLIBCXX_SYNCSTREAM
30 #define _GLIBCXX_SYNCSTREAM 1
32 #pragma GCC system_header
34 #include <bits/requires_hosted.h> // iostreams
36 #include <bits/c++config.h>
38 #define __glibcxx_want_syncbuf
39 #include <bits/version.h>
41 #ifdef __cpp_lib_syncbuf // C++ >= 20 && HOSTED && CXX11ABI
44 #include <bits/alloc_traits.h>
45 #include <bits/allocator.h>
46 #include <bits/functexcept.h>
47 #include <bits/functional_hash.h>
48 #include <bits/std_mutex.h>
50 namespace std _GLIBCXX_VISIBILITY(default)
52 _GLIBCXX_BEGIN_NAMESPACE_VERSION
54 template<typename _CharT, typename _Traits, typename _Alloc>
55 class basic_syncbuf : public __syncbuf_base<_CharT, _Traits>
58 using char_type = _CharT;
59 using int_type = typename _Traits::int_type;
60 using pos_type = typename _Traits::pos_type;
61 using off_type = typename _Traits::off_type;
62 using traits_type = _Traits;
63 using allocator_type = _Alloc;
64 using streambuf_type = basic_streambuf<_CharT, _Traits>;
67 : basic_syncbuf(nullptr, allocator_type{})
71 basic_syncbuf(streambuf_type* __obuf)
72 : basic_syncbuf(__obuf, allocator_type{})
75 basic_syncbuf(streambuf_type* __obuf, const allocator_type& __alloc)
76 : __syncbuf_base<_CharT, _Traits>(__obuf)
81 basic_syncbuf(basic_syncbuf&& __other)
82 : __syncbuf_base<_CharT, _Traits>(__other._M_wrapped)
83 , _M_impl(std::move(__other._M_impl))
84 , _M_mtx(std::move(__other._M_mtx))
86 this->_M_emit_on_sync = __other._M_emit_on_sync;
87 this->_M_needs_sync = __other._M_needs_sync;
88 __other._M_wrapped = nullptr;
102 operator=(basic_syncbuf&& __other)
106 _M_impl = std::move(__other._M_impl);
107 this->_M_emit_on_sync = __other._M_emit_on_sync;
108 this->_M_needs_sync = __other._M_needs_sync;
109 this->_M_wrapped = __other._M_wrapped;
110 __other._M_wrapped = nullptr;
111 _M_mtx = std::move(__other._M_mtx);
117 swap(basic_syncbuf& __other)
119 using _ATr = allocator_traits<_Alloc>;
120 if constexpr (!_ATr::propagate_on_container_swap::value)
121 __glibcxx_assert(get_allocator() == __other.get_allocator());
123 std::swap(_M_impl, __other._M_impl);
124 std::swap(this->_M_emit_on_sync, __other._M_emit_on_sync);
125 std::swap(this->_M_needs_sync, __other._M_needs_sync);
126 std::swap(this->_M_wrapped, __other._M_wrapped);
127 std::swap(_M_mtx, __other._M_mtx);
133 if (!this->_M_wrapped)
136 auto __s = std::move(_M_impl).str();
138 const lock_guard<__mutex> __l(_M_mtx);
139 if (auto __size = __s.size())
141 auto __n = this->_M_wrapped->sputn(__s.data(), __size);
145 _M_impl.str(std::move(__s));
150 if (this->_M_needs_sync)
152 this->_M_needs_sync = false;
153 if (this->_M_wrapped->pubsync() != 0)
160 get_wrapped() const noexcept
161 { return this->_M_wrapped; }
164 get_allocator() const noexcept
165 { return _M_impl.get_allocator(); }
168 set_emit_on_sync(bool __b) noexcept
169 { this->_M_emit_on_sync = __b; }
175 this->_M_needs_sync = true;
176 if (this->_M_emit_on_sync && !emit())
182 overflow(int_type __c) override
184 int_type __eof = traits_type::eof();
185 if (__builtin_expect(!traits_type::eq_int_type(__c, __eof), true))
186 return _M_impl.sputc(__c);
191 xsputn(const char_type* __s, streamsize __n) override
192 { return _M_impl.sputn(__s, __n); }
195 basic_stringbuf<char_type, traits_type, allocator_type> _M_impl;
199 #if _GLIBCXX_HAS_GTHREADS
203 : _M_mtx(__t ? &_S_get_mutex(__t) : nullptr)
207 swap(__mutex& __other) noexcept
208 { std::swap(_M_mtx, __other._M_mtx); }
222 // FIXME: This should be put in the .so
224 _S_get_mutex(void* __t)
226 const unsigned char __mask = 0xf;
227 static mutex __m[__mask + 1];
229 auto __key = _Hash_impl::hash(__t) & __mask;
234 void swap(__mutex&&) noexcept { }
238 __mutex(__mutex&&) = default;
239 __mutex& operator=(__mutex&&) = default;
244 template <typename _CharT, typename _Traits, typename _Alloc>
245 class basic_osyncstream : public basic_ostream<_CharT, _Traits>
247 using __ostream_type = basic_ostream<_CharT, _Traits>;
251 using char_type = _CharT;
252 using traits_type = _Traits;
253 using allocator_type = _Alloc;
254 using int_type = typename traits_type::int_type;
255 using pos_type = typename traits_type::pos_type;
256 using off_type = typename traits_type::off_type;
257 using syncbuf_type = basic_syncbuf<_CharT, _Traits, _Alloc>;
258 using streambuf_type = typename syncbuf_type::streambuf_type;
261 syncbuf_type _M_syncbuf;
264 basic_osyncstream(streambuf_type* __buf, const allocator_type& __a)
265 : _M_syncbuf(__buf, __a)
266 { this->init(std::__addressof(_M_syncbuf)); }
268 explicit basic_osyncstream(streambuf_type* __buf)
270 { this->init(std::__addressof(_M_syncbuf)); }
272 basic_osyncstream(basic_ostream<char_type, traits_type>& __os,
273 const allocator_type& __a)
274 : basic_osyncstream(__os.rdbuf(), __a)
275 { this->init(std::__addressof(_M_syncbuf)); }
277 explicit basic_osyncstream(basic_ostream<char_type, traits_type>& __os)
278 : basic_osyncstream(__os.rdbuf())
279 { this->init(std::__addressof(_M_syncbuf)); }
281 basic_osyncstream(basic_osyncstream&& __rhs) noexcept
282 : __ostream_type(std::move(__rhs)),
283 _M_syncbuf(std::move(__rhs._M_syncbuf))
284 { __ostream_type::set_rdbuf(std::__addressof(_M_syncbuf)); }
286 ~basic_osyncstream() = default;
288 basic_osyncstream& operator=(basic_osyncstream&&) = default;
290 syncbuf_type* rdbuf() const noexcept
291 { return const_cast<syncbuf_type*>(&_M_syncbuf); }
293 streambuf_type* get_wrapped() const noexcept
294 { return _M_syncbuf.get_wrapped(); }
298 if (!_M_syncbuf.emit())
299 this->setstate(ios_base::failbit);
303 template <class _CharT, class _Traits, class _Allocator>
305 swap(basic_syncbuf<_CharT, _Traits, _Allocator>& __x,
306 basic_syncbuf<_CharT, _Traits, _Allocator>& __y) noexcept
309 using syncbuf = basic_syncbuf<char>;
310 using wsyncbuf = basic_syncbuf<wchar_t>;
312 using osyncstream = basic_osyncstream<char>;
313 using wosyncstream = basic_osyncstream<wchar_t>;
314 _GLIBCXX_END_NAMESPACE_VERSION
316 #endif // __cpp_lib_syncbuf
318 #endif /* _GLIBCXX_SYNCSTREAM */