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// Temporary buffer implementation -*- C++ -*-
// Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
// Free Software Foundation, Inc.
//
// 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/>.
/*
*
* Copyright (c) 1994
* Hewlett-Packard Company
*
* Permission to use, copy, modify, distribute and sell this software
* and its documentation for any purpose is hereby granted without fee,
* provided that the above copyright notice appear in all copies and
* that both that copyright notice and this permission notice appear
* in supporting documentation. Hewlett-Packard Company makes no
* representations about the suitability of this software for any
* purpose. It is provided "as is" without express or implied warranty.
*
*
* Copyright (c) 1996,1997
* Silicon Graphics Computer Systems, Inc.
*
* Permission to use, copy, modify, distribute and sell this software
* and its documentation for any purpose is hereby granted without fee,
* provided that the above copyright notice appear in all copies and
* that both that copyright notice and this permission notice appear
* in supporting documentation. Silicon Graphics makes no
* representations about the suitability of this software for any
* purpose. It is provided "as is" without express or implied warranty.
*/
/** @file stl_tempbuf.h
* This is an internal header file, included by other library headers.
* You should not attempt to use it directly.
*/
#ifndef _STL_TEMPBUF_H
#define _STL_TEMPBUF_H 1
#include <bits/stl_algobase.h>
#include <bits/stl_construct.h>
#include <bits/stl_uninitialized.h>
_GLIBCXX_BEGIN_NAMESPACE(std)
/**
* @brief Allocates a temporary buffer.
* @param len The number of objects of type Tp.
* @return See full description.
*
* Reinventing the wheel, but this time with prettier spokes!
*
* This function tries to obtain storage for @c len adjacent Tp
* objects. The objects themselves are not constructed, of course.
* A pair<> is returned containing "the buffer s address and
* capacity (in the units of sizeof(Tp)), or a pair of 0 values if
* no storage can be obtained." Note that the capacity obtained
* may be less than that requested if the memory is unavailable;
* you should compare len with the .second return value.
*
* Provides the nothrow exception guarantee.
*/
template<typename _Tp>
pair<_Tp*, ptrdiff_t>
get_temporary_buffer(ptrdiff_t __len)
{
const ptrdiff_t __max =
__gnu_cxx::__numeric_traits<ptrdiff_t>::__max / sizeof(_Tp);
if (__len > __max)
__len = __max;
while (__len > 0)
{
_Tp* __tmp = static_cast<_Tp*>(::operator new(__len * sizeof(_Tp),
std::nothrow));
if (__tmp != 0)
return std::pair<_Tp*, ptrdiff_t>(__tmp, __len);
__len /= 2;
}
return std::pair<_Tp*, ptrdiff_t>(static_cast<_Tp*>(0), 0);
}
/**
* @brief The companion to get_temporary_buffer().
* @param p A buffer previously allocated by get_temporary_buffer.
* @return None.
*
* Frees the memory pointed to by p.
*/
template<typename _Tp>
inline void
return_temporary_buffer(_Tp* __p)
{ ::operator delete(__p, std::nothrow); }
/**
* This class is used in two places: stl_algo.h and ext/memory,
* where it is wrapped as the temporary_buffer class. See
* temporary_buffer docs for more notes.
*/
template<typename _ForwardIterator, typename _Tp>
class _Temporary_buffer
{
// concept requirements
__glibcxx_class_requires(_ForwardIterator, _ForwardIteratorConcept)
public:
typedef _Tp value_type;
typedef value_type* pointer;
typedef pointer iterator;
typedef ptrdiff_t size_type;
protected:
size_type _M_original_len;
size_type _M_len;
pointer _M_buffer;
public:
/// As per Table mumble.
size_type
size() const
{ return _M_len; }
/// Returns the size requested by the constructor; may be >size().
size_type
requested_size() const
{ return _M_original_len; }
/// As per Table mumble.
iterator
begin()
{ return _M_buffer; }
/// As per Table mumble.
iterator
end()
{ return _M_buffer + _M_len; }
/**
* Constructs a temporary buffer of a size somewhere between
* zero and the size of the given range.
*/
_Temporary_buffer(_ForwardIterator __first, _ForwardIterator __last);
~_Temporary_buffer()
{
std::_Destroy(_M_buffer, _M_buffer + _M_len);
std::return_temporary_buffer(_M_buffer);
}
private:
// Disable copy constructor and assignment operator.
_Temporary_buffer(const _Temporary_buffer&);
void
operator=(const _Temporary_buffer&);
};
template<typename _ForwardIterator, typename _Tp>
_Temporary_buffer<_ForwardIterator, _Tp>::
_Temporary_buffer(_ForwardIterator __first, _ForwardIterator __last)
: _M_original_len(std::distance(__first, __last)),
_M_len(0), _M_buffer(0)
{
__try
{
std::pair<pointer, size_type> __p(std::get_temporary_buffer<
value_type>(_M_original_len));
_M_buffer = __p.first;
_M_len = __p.second;
if (!__is_pod(_Tp) && _M_len > 0)
std::uninitialized_fill_n(_M_buffer, _M_len, *__first);
}
__catch(...)
{
std::return_temporary_buffer(_M_buffer);
_M_buffer = 0;
_M_len = 0;
__throw_exception_again;
}
}
_GLIBCXX_END_NAMESPACE
#endif /* _STL_TEMPBUF_H */
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