memory (align): Define.
2014-10-13 Rüdiger Sonderfeld <ruediger@c-plusplus.de> * include/std/memory (align): Define. * testsuite/20_util/align/1.cc: New. From-SVN: r216143
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2014-10-13 Rüdiger Sonderfeld <ruediger@c-plusplus.de>
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* include/std/memory (align): Define.
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* testsuite/20_util/align/1.cc: New.
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2014-10-13 Marc Glisse <marc.glisse@inria.fr>
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PR libstdc++/61347
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@ -87,4 +87,46 @@
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# include <backward/auto_ptr.h>
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#endif
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#if __cplusplus >= 201103L
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# include <cstdint>
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# ifdef _GLIBCXX_USE_C99_STDINT_TR1
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namespace std _GLIBCXX_VISIBILITY(default)
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{
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_GLIBCXX_BEGIN_NAMESPACE_VERSION
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/**
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* @brief Fit aligned storage in buffer.
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*
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* [ptr.align]
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*
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* This function tries to fit @a __size bytes of storage with alignment
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* @a __align into the buffer @a __ptr of size @a __space bytes. If such
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* a buffer fits then @a __ptr is changed to point to the first byte of the
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* aligned storage and @a __space is reduced by the bytes used for alignment.
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*
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* @param __align A fundamental or extended alignment value.
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* @param __size Size of the aligned storage required.
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* @param __ptr Pointer to a buffer of @a __space bytes.
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* @param __space Size of the buffer pointed to by @a __ptr.
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* @return the updated pointer if the aligned storage fits, otherwise nullptr.
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*/
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inline void*
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align(size_t __align, size_t __size, void*& __ptr, size_t& __space) noexcept
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{
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const size_t __diff = __align - reinterpret_cast<uintptr_t>(__ptr) % __align;
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if (__diff + __size >= __space)
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return nullptr;
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else
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{
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__space -= __diff;
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__ptr = static_cast<char*>(__ptr) + __diff;
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return __ptr;
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}
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}
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_GLIBCXX_END_NAMESPACE_VERSION
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} // namespace
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#endif // _GLIBCXX_USE_C99_STDINT_TR1
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#endif // C++11
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#endif /* _GLIBCXX_MEMORY */
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// { dg-options " -std=gnu++11 " }
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// 2014-04-16 Rüdiger Sonderfeld <ruediger@c-plusplus.de>
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// Copyright (C) 2014 Free Software Foundation, Inc.
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//
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// This file is part of the GNU ISO C++ Library. This library is free
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// software; you can redistribute it and/or modify it under the terms
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// of the GNU General Public License as published by the Free Software
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// Foundation; either version 3, or (at your option) any later
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// version.
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// This library is distributed in the hope that it will be useful, but
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// WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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// General Public License for more details.
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// You should have received a copy of the GNU General Public License
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// along with this library; see the file COPYING3. If not see
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// <http://www.gnu.org/licenses/>.
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// C++11 [ptr.align] (20.6.5): std::align
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#include <memory>
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#include <cstdint>
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#include <testsuite_hooks.h>
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void
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test01()
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{
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bool test __attribute__((unused)) = true;
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size_t space = 100;
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void* ptr = new char[space];
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char* const orig_ptr = static_cast<char*>(ptr);
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char* old_ptr = orig_ptr;
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const size_t orig_space = space;
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size_t old_space = space;
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const size_t alignment = 16;
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const size_t size = 10;
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while( void* const r = std::align(alignment, size, ptr, space) )
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{
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VERIFY( r == ptr );
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uintptr_t p = reinterpret_cast<uintptr_t>(ptr);
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VERIFY( p % alignment == 0 );
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char* const x = static_cast<char*>(ptr);
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VERIFY( x - old_ptr == old_space - space );
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VERIFY( (void*)x < (void*)(orig_ptr + orig_space) );
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VERIFY( (void*)(x + size) < (void*)(orig_ptr + orig_space) );
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ptr = x + size;
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old_ptr = x;
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old_space = space;
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space -= size;
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}
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delete [] orig_ptr;
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}
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int main()
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{
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test01();
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}
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