gcc/libstdc++-v3/include/std/spanstream
Jonathan Wakely ca97c87758 libstdc++: Add <spanstream> declarations to <iosfwd> [PR105284]
libstdc++-v3/ChangeLog:

	PR libstdc++/105284
	* include/std/iosfwd: Add declarations for <spanstream> class
	templates and typedefs.
	* include/std/spanstream (basic_spanbuf, basic_ispanstream)
	(basic_ospanstream, basic_spanstream): Remove default template
	arguments.
	* testsuite/27_io/headers/iosfwd/synopsis.cc: Add <spanstream>
	declarations.
	* testsuite/27_io/headers/iosfwd/types.cc: Check <spanstream>
	default arguments.
2022-05-10 16:40:22 +01:00

454 lines
12 KiB
C++

// Streams based on std::span -*- C++ -*-
// Copyright The GNU Toolchain Authors.
//
// 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 spanstream
* This is a Standard C++ Library header.
*/
#ifndef _GLIBCXX_SPANSTREAM
#define _GLIBCXX_SPANSTREAM 1
#pragma GCC system_header
#if __cplusplus > 202002L
#include <span>
#include <streambuf>
#include <istream>
#include <ostream>
#include <bits/ranges_base.h>
#if __cpp_lib_span
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
#define __cpp_lib_spanstream 202106L
template<typename _CharT, typename _Traits>
class basic_spanbuf
: public basic_streambuf<_CharT, _Traits>
{
using __streambuf_type = basic_streambuf<_CharT, _Traits>;
public:
using char_type = _CharT;
using int_type = typename _Traits::int_type;
using pos_type = typename _Traits::pos_type;
using off_type = typename _Traits::off_type;
using traits_type = _Traits;
// [spanbuf.ctor], constructors
basic_spanbuf() : basic_spanbuf(ios_base::in | ios_base::out)
{ }
explicit
basic_spanbuf(ios_base::openmode __which)
: __streambuf_type(), _M_mode(__which)
{ }
explicit
basic_spanbuf(std::span<_CharT> __s,
ios_base::openmode __which = ios_base::in | ios_base::out)
: __streambuf_type(), _M_mode(__which)
{ span(__s); }
basic_spanbuf(const basic_spanbuf&) = delete;
/** Move constructor.
*
* Transfers the buffer and pointers into the get and put areas from
* `__rhs` to `*this`.
*
* In this implementation `rhs` is left unchanged,
* but that is not guaranteed by the standard.
*/
basic_spanbuf(basic_spanbuf&& __rhs)
: __streambuf_type(__rhs), _M_mode(__rhs._M_mode), _M_buf(__rhs._M_buf)
{ }
// [spanbuf.assign], assignment and swap
basic_spanbuf& operator=(const basic_spanbuf&) = delete;
basic_spanbuf&
operator=(basic_spanbuf&& __rhs)
{
basic_spanbuf(std::move(__rhs)).swap(*this);
return *this;
}
void
swap(basic_spanbuf& __rhs)
{
__streambuf_type::swap(__rhs);
std::swap(_M_mode, __rhs._M_mode);
std::swap(_M_buf, __rhs._M_buf);
}
// [spanbuf.members], member functions
std::span<_CharT>
span() const noexcept
{
if (_M_mode & ios_base::out)
return {this->pbase(), this->pptr()};
else
return _M_buf;
}
void
span(std::span<_CharT> __s) noexcept
{
_M_buf = __s;
if (_M_mode & ios_base::out)
{
this->setp(__s.data(), __s.data() + __s.size());
if (_M_mode & ios_base::ate)
this->pbump(__s.size());
}
if (_M_mode & ios_base::in)
this->setg(__s.data(), __s.data(), __s.data() + __s.size());
}
protected:
// [spanbuf.virtuals], overridden virtual functions
basic_streambuf<_CharT, _Traits>*
setbuf(_CharT* __s, streamsize __n) override
{
span({__s, __n});
return this;
}
pos_type
seekoff(off_type __off, ios_base::seekdir __way,
ios_base::openmode __which = ios_base::in | ios_base::out) override
{
pos_type __ret = pos_type(off_type(-1));
if (__way == ios_base::beg)
{
if (0 <= __off && __off <= _M_buf.size())
{
if (__which & ios_base::in)
this->setg(this->eback(), this->eback() + __off, this->egptr());
if (__which & ios_base::out)
{
this->setp(this->pbase(), this->epptr());
this->pbump(__off);
}
__ret = pos_type(__off);
}
}
else
{
off_type __base;
__which &= (ios_base::in|ios_base::out);
if (__which == ios_base::out)
__base = this->pptr() - this->pbase();
else if (__way == ios_base::cur)
{
if (__which == ios_base::in)
__base = this->gptr() - this->eback();
else
return __ret;
}
else if (__way == ios_base::end)
__base = _M_buf.size();
if (__builtin_add_overflow(__base, __off, &__off))
return __ret;
if (__off < 0 || __off > _M_buf.size())
return __ret;
if (__which & ios_base::in)
this->setg(this->eback(), this->eback() + __off, this->egptr());
if (__which & ios_base::out)
{
this->setp(this->pbase(), this->epptr());
this->pbump(__off);
}
__ret = pos_type(__off);
}
return __ret;
}
pos_type
seekpos(pos_type __sp,
ios_base::openmode __which = ios_base::in | ios_base::out) override
{ return seekoff(off_type(__sp), ios_base::beg, __which); }
private:
ios_base::openmode _M_mode;
std::span<_CharT> _M_buf;
};
template<typename _CharT, typename _Traits>
inline void
swap(basic_spanbuf<_CharT, _Traits>& __x,
basic_spanbuf<_CharT, _Traits>& __y)
{ __x.swap(__y); }
using spanbuf = basic_spanbuf<char>;
using wspanbuf = basic_spanbuf<wchar_t>;
template<typename _CharT, typename _Traits>
class basic_ispanstream
: public basic_istream<_CharT, _Traits>
{
using __istream_type = basic_istream<_CharT, _Traits>;
public:
using char_type = _CharT;
using int_type = typename _Traits::int_type;
using pos_type = typename _Traits::pos_type;
using off_type = typename _Traits::off_type;
using traits_type = _Traits;
// [ispanstream.ctor], constructors
explicit
basic_ispanstream(std::span<_CharT> __s,
ios_base::openmode __which = ios_base::in)
: __istream_type(std::__addressof(_M_sb)),
_M_sb(__s, __which | ios_base::in)
{ }
basic_ispanstream(const basic_ispanstream&) = delete;
basic_ispanstream(basic_ispanstream&& __rhs)
: __istream_type(std::move(__rhs)), _M_sb(std::move(__rhs._M_sb))
{
__istream_type::set_rdbuf(std::addressof(_M_sb));
}
template<typename _Ros>
requires ranges::borrowed_range<_Ros>
&& (!convertible_to<_Ros, std::span<_CharT>>)
&& convertible_to<_Ros, std::span<const _CharT>>
explicit
basic_ispanstream(_Ros&& __s)
: __istream_type(std::__addressof(_M_sb)),
_M_sb(ios_base::in)
{
std::span<const _CharT> __sp(std::forward<_Ros>(__s));
_M_sb.span({const_cast<_CharT*>(__sp.data()), __sp.size()});
}
// [ispanstream.assign], assignment and swap
basic_ispanstream& operator=(const basic_ispanstream&) = delete;
basic_ispanstream& operator=(basic_ispanstream&& __rhs) = default;
void
swap(basic_ispanstream& __rhs)
{
__istream_type::swap(__rhs);
_M_sb.swap(__rhs._M_sb);
}
// [ispanstream.members], member functions
basic_spanbuf<_CharT, _Traits>*
rdbuf() const noexcept
{
return const_cast<basic_spanbuf<_CharT, _Traits>*>(std::__addressof(_M_sb));
}
std::span<const _CharT>
span() const noexcept
{ return _M_sb.span(); }
void
span(std::span<_CharT> __s) noexcept
{ return _M_sb.span(__s); }
template<typename _Ros>
requires ranges::borrowed_range<_Ros>
&& (!convertible_to<_Ros, std::span<_CharT>>)
&& convertible_to<_Ros, std::span<const _CharT>>
void
span(_Ros&& __s) noexcept
{
std::span<const _CharT> __sp(std::forward<_Ros>(__s));
_M_sb.span({const_cast<_CharT*>(__sp.data()), __sp.size()});
}
private:
basic_spanbuf<_CharT, _Traits> _M_sb;
};
template<typename _CharT, typename _Traits>
inline void
swap(basic_ispanstream<_CharT, _Traits>& __x,
basic_ispanstream<_CharT, _Traits>& __y)
{ __x.swap(__y); }
using ispanstream = basic_ispanstream<char>;
using wispanstream = basic_ispanstream<wchar_t>;
template<typename _CharT, typename _Traits>
class basic_ospanstream
: public basic_ostream<_CharT, _Traits>
{
using __ostream_type = basic_ostream<_CharT, _Traits>;
public:
using char_type = _CharT;
using int_type = typename _Traits::int_type;
using pos_type = typename _Traits::pos_type;
using off_type = typename _Traits::off_type;
using traits_type = _Traits;
// [ospanstream.ctor], constructors
explicit
basic_ospanstream(std::span<_CharT> __s,
ios_base::openmode __which = ios_base::out)
: __ostream_type(std::__addressof(_M_sb)),
_M_sb(__s, __which | ios_base::in)
{ }
basic_ospanstream(const basic_ospanstream&) = delete;
basic_ospanstream(basic_ospanstream&& __rhs)
: __ostream_type(std::move(__rhs)), _M_sb(std::move(__rhs._M_sb))
{
__ostream_type::set_rdbuf(std::addressof(_M_sb));
}
// [ospanstream.assign], assignment and swap
basic_ospanstream& operator=(const basic_ospanstream&) = delete;
basic_ospanstream& operator=(basic_ospanstream&& __rhs) = default;
void
swap(basic_ospanstream& __rhs)
{
__ostream_type::swap(__rhs);
_M_sb.swap(__rhs._M_sb);
}
// [ospanstream.members], member functions
basic_spanbuf<_CharT, _Traits>*
rdbuf() const noexcept
{
return const_cast<basic_spanbuf<_CharT, _Traits>*>(std::__addressof(_M_sb));
}
std::span<_CharT>
span() const noexcept
{ return _M_sb.span(); }
void
span(std::span<_CharT> __s) noexcept
{ return _M_sb.span(__s); }
private:
basic_spanbuf<_CharT, _Traits> _M_sb;
};
template<typename _CharT, typename _Traits>
inline void
swap(basic_ospanstream<_CharT, _Traits>& __x,
basic_ospanstream<_CharT, _Traits>& __y)
{ __x.swap(__y); }
using ospanstream = basic_ospanstream<char>;
using wospanstream = basic_ospanstream<wchar_t>;
template<typename _CharT, typename _Traits>
class basic_spanstream
: public basic_iostream<_CharT, _Traits>
{
using __iostream_type = basic_iostream<_CharT, _Traits>;
public:
using char_type = _CharT;
using int_type = typename _Traits::int_type;
using pos_type = typename _Traits::pos_type;
using off_type = typename _Traits::off_type;
using traits_type = _Traits;
// [spanstream.ctor], constructors
explicit
basic_spanstream(std::span<_CharT> __s,
ios_base::openmode __which = ios_base::out | ios_base::in)
: __iostream_type(std::__addressof(_M_sb)),
_M_sb(__s, __which)
{ }
basic_spanstream(const basic_spanstream&) = delete;
basic_spanstream(basic_spanstream&& __rhs)
: __iostream_type(std::move(__rhs)), _M_sb(std::move(__rhs._M_sb))
{
__iostream_type::set_rdbuf(std::addressof(_M_sb));
}
// [spanstream.assign], assignment and swap
basic_spanstream& operator=(const basic_spanstream&) = delete;
basic_spanstream& operator=(basic_spanstream&& __rhs) = default;
void
swap(basic_spanstream& __rhs)
{
__iostream_type::swap(__rhs);
_M_sb.swap(__rhs._M_sb);
}
// [spanstream.members], members
basic_spanbuf<_CharT, _Traits>*
rdbuf() const noexcept
{
return const_cast<basic_spanbuf<_CharT, _Traits>*>(std::__addressof(_M_sb));
}
std::span<_CharT>
span() const noexcept
{ return _M_sb.span(); }
void
span(std::span<_CharT> __s) noexcept
{ return _M_sb.span(__s); }
private:
basic_spanbuf<_CharT, _Traits> _M_sb;
};
template<typename _CharT, typename _Traits>
inline void
swap(basic_spanstream<_CharT, _Traits>& __x,
basic_spanstream<_CharT, _Traits>& __y)
{ __x.swap(__y); }
using spanstream = basic_spanstream<char>;
using wspanstream = basic_spanstream<wchar_t>;
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace std
#endif // __cpp_lib_span
#endif // C++23
#endif // _GLIBCXX_SPANSTREAM