forked from boostorg/smart_ptr
153 lines
3.3 KiB
C++
153 lines
3.3 KiB
C++
#ifndef BOOST_DETAIL_SHARED_ARRAY_NMT_HPP_INCLUDED
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#define BOOST_DETAIL_SHARED_ARRAY_NMT_HPP_INCLUDED
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//
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// detail/shared_array_nmt.hpp - shared_array.hpp without member templates
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//
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// (C) Copyright Greg Colvin and Beman Dawes 1998, 1999.
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// Copyright (c) 2001, 2002 Peter Dimov
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//
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// Permission to copy, use, modify, sell and distribute this software
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// is granted provided this copyright notice appears in all copies.
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// This software is provided "as is" without express or implied
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// warranty, and with no claim as to its suitability for any purpose.
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//
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// See http://www.boost.org/libs/smart_ptr/shared_array.htm for documentation.
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//
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#include <boost/assert.hpp>
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#include <boost/checked_delete.hpp>
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#include <boost/throw_exception.hpp>
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#include <boost/detail/atomic_count.hpp>
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#include <cstddef> // for std::ptrdiff_t
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#include <algorithm> // for std::swap
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#include <functional> // for std::less
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#include <new> // for std::bad_alloc
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namespace boost
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{
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template<class T> class shared_array
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{
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private:
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typedef detail::atomic_count count_type;
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public:
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typedef T element_type;
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explicit shared_array(T * p = 0): px(p)
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{
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#ifndef BOOST_NO_EXCEPTIONS
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try // prevent leak if new throws
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{
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pn = new count_type(1);
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}
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catch(...)
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{
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boost::checked_array_delete(p);
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throw;
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}
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#else
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pn = new count_type(1);
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if(pn == 0)
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{
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boost::checked_array_delete(p);
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boost::throw_exception(std::bad_alloc());
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}
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#endif
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}
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~shared_array()
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{
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if(--*pn == 0)
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{
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boost::checked_array_delete(px);
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delete pn;
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}
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}
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shared_array(shared_array const & r) : px(r.px) // never throws
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{
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pn = r.pn;
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++*pn;
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}
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shared_array & operator=(shared_array const & r)
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{
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shared_array(r).swap(*this);
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return *this;
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}
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void reset(T * p = 0)
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{
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BOOST_ASSERT(p == 0 || p != px);
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shared_array(p).swap(*this);
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}
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T * get() const // never throws
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{
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return px;
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}
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T & operator[](std::ptrdiff_t i) const // never throws
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{
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BOOST_ASSERT(px != 0);
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BOOST_ASSERT(i >= 0);
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return px[i];
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}
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long use_count() const // never throws
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{
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return *pn;
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}
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bool unique() const // never throws
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{
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return *pn == 1;
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}
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void swap(shared_array<T> & other) // never throws
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{
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std::swap(px, other.px);
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std::swap(pn, other.pn);
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}
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private:
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T * px; // contained pointer
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count_type * pn; // ptr to reference counter
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}; // shared_array
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template<class T, class U> inline bool operator==(shared_array<T> const & a, shared_array<U> const & b)
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{
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return a.get() == b.get();
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}
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template<class T, class U> inline bool operator!=(shared_array<T> const & a, shared_array<U> const & b)
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{
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return a.get() != b.get();
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}
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template<class T> inline bool operator<(shared_array<T> const & a, shared_array<T> const & b)
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{
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return std::less<T*>()(a.get(), b.get());
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}
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template<class T> void swap(shared_array<T> & a, shared_array<T> & b)
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{
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a.swap(b);
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}
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} // namespace boost
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#endif // #ifndef BOOST_DETAIL_SHARED_ARRAY_NMT_HPP_INCLUDED
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