# stl_tempbuf.h

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    00001 // Temporary buffer implementation -*- C++ -*-
    00002
    00003 // Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006
    00004 // Free Software Foundation, Inc.
    00005 //
    00006 // This file is part of the GNU ISO C++ Library.  This library is free
    00007 // software; you can redistribute it and/or modify it under the
    00008 // terms of the GNU General Public License as published by the
    00009 // Free Software Foundation; either version 2, or (at your option)
    00010 // any later version.
    00011
    00012 // This library is distributed in the hope that it will be useful,
    00013 // but WITHOUT ANY WARRANTY; without even the implied warranty of
    00014 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    00015 // GNU General Public License for more details.
    00016
    00017 // You should have received a copy of the GNU General Public License along
    00018 // with this library; see the file COPYING.  If not, write to the Free
    00019 // Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
    00020 // USA.
    00021
    00022 // As a special exception, you may use this file as part of a free software
    00023 // library without restriction.  Specifically, if other files instantiate
    00024 // templates or use macros or inline functions from this file, or you compile
    00025 // this file and link it with other files to produce an executable, this
    00026 // file does not by itself cause the resulting executable to be covered by
    00027 // the GNU General Public License.  This exception does not however
    00028 // invalidate any other reasons why the executable file might be covered by
    00029 // the GNU General Public License.
    00030
    00031 /*
    00032  *
    00033  * Copyright (c) 1994
    00034  * Hewlett-Packard Company
    00035  *
    00036  * Permission to use, copy, modify, distribute and sell this software
    00037  * and its documentation for any purpose is hereby granted without fee,
    00038  * provided that the above copyright notice appear in all copies and
    00039  * that both that copyright notice and this permission notice appear
    00040  * in supporting documentation.  Hewlett-Packard Company makes no
    00041  * representations about the suitability of this software for any
    00042  * purpose.  It is provided "as is" without express or implied warranty.
    00043  *
    00044  *
    00045  * Copyright (c) 1996,1997
    00046  * Silicon Graphics Computer Systems, Inc.
    00047  *
    00048  * Permission to use, copy, modify, distribute and sell this software
    00049  * and its documentation for any purpose is hereby granted without fee,
    00050  * provided that the above copyright notice appear in all copies and
    00051  * that both that copyright notice and this permission notice appear
    00052  * in supporting documentation.  Silicon Graphics makes no
    00053  * representations about the suitability of this software for any
    00054  * purpose.  It is provided "as is" without express or implied warranty.
    00055  */
    00056
    00057 /** @file stl_tempbuf.h
    00058  *  This is an internal header file, included by other library headers.
    00059  *  You should not attempt to use it directly.
    00060  */
    00061
    00062 #ifndef _TEMPBUF_H
    00063 #define _TEMPBUF_H 1
    00064
    00065 #include <memory>
    00066
    00067 _GLIBCXX_BEGIN_NAMESPACE(std)
    00068
    00069   /**
    00070    *  @if maint
    00071    *  This class is used in two places: stl_algo.h and ext/memory,
    00072    *  where it is wrapped as the temporary_buffer class.  See
    00073    *  temporary_buffer docs for more notes.
    00074    *  @endif
    00075    */
    00076   template<typename _ForwardIterator, typename _Tp>
    00077     class _Temporary_buffer
    00078     {
    00079       // concept requirements
    00080       __glibcxx_class_requires(_ForwardIterator, _ForwardIteratorConcept)
    00081
    00082     public:
    00083       typedef _Tp         value_type;
    00084       typedef value_type* pointer;
    00085       typedef pointer     iterator;
    00086       typedef ptrdiff_t   size_type;
    00087
    00088     protected:
    00089       size_type  _M_original_len;
    00090       size_type  _M_len;
    00091       pointer    _M_buffer;
    00092
    00093       void
    00094       _M_initialize_buffer(const _Tp&, __true_type) { }
    00095
    00096       void
    00097       _M_initialize_buffer(const _Tp& __val, __false_type)
    00098       { std::uninitialized_fill_n(_M_buffer, _M_len, __val); }
    00099
    00100     public:
    00101       /// As per Table mumble.
    00102       size_type
    00103       size() const
    00104       { return _M_len; }
    00105
    00106       /// Returns the size requested by the constructor; may be >size().
    00107       size_type
    00108       requested_size() const
    00109       { return _M_original_len; }
    00110
    00111       /// As per Table mumble.
    00112       iterator
    00113       begin()
    00114       { return _M_buffer; }
    00115
    00116       /// As per Table mumble.
    00117       iterator
    00118       end()
    00119       { return _M_buffer + _M_len; }
    00120
    00121       /**
    00122        * Constructs a temporary buffer of a size somewhere between
    00123        * zero and the size of the given range.
    00124        */
    00125       _Temporary_buffer(_ForwardIterator __first, _ForwardIterator __last);
    00126
    00127       ~_Temporary_buffer()
    00128       {
    00129     std::_Destroy(_M_buffer, _M_buffer + _M_len);
    00130     std::return_temporary_buffer(_M_buffer);
    00131       }
    00132
    00133     private:
    00134       // Disable copy constructor and assignment operator.
    00135       _Temporary_buffer(const _Temporary_buffer&);
    00136
    00137       void
    00138       operator=(const _Temporary_buffer&);
    00139     };
    00140
    00141
    00142   template<typename _ForwardIterator, typename _Tp>
    00143     _Temporary_buffer<_ForwardIterator, _Tp>::
    00144     _Temporary_buffer(_ForwardIterator __first, _ForwardIterator __last)
    00145     : _M_original_len(std::distance(__first, __last)),
    00146       _M_len(0), _M_buffer(0)
    00147     {
    00148       // Workaround for a __type_traits bug in the pre-7.3 compiler.
    00149       typedef typename std::__is_scalar<_Tp>::__type _Trivial;
    00150
    00151       try
    00152     {
    00153       pair<pointer, size_type> __p(get_temporary_buffer<
    00154                        value_type>(_M_original_len));
    00155       _M_buffer = __p.first;
    00156       _M_len = __p.second;
    00157       if (_M_len > 0)
    00158         _M_initialize_buffer(*__first, _Trivial());
    00159     }
    00160       catch(...)
    00161     {
    00162       std::return_temporary_buffer(_M_buffer);
    00163       _M_buffer = 0;
    00164       _M_len = 0;
    00165       __throw_exception_again;
    00166     }
    00167     }
    00168
    00169 _GLIBCXX_END_NAMESPACE
    00170
    00171 #endif /* _TEMPBUF_H */
    00172