# stl_tempbuf.h

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    00001 // Temporary buffer implementation -*- C++ -*-
    00002
    00003 // Copyright (C) 2001, 2002, 2004 Free Software Foundation, Inc.
    00004 //
    00005 // This file is part of the GNU ISO C++ Library.  This library is free
    00006 // software; you can redistribute it and/or modify it under the
    00007 // terms of the GNU General Public License as published by the
    00008 // Free Software Foundation; either version 2, or (at your option)
    00009 // any later version.
    00010
    00011 // This library is distributed in the hope that it will be useful,
    00012 // but WITHOUT ANY WARRANTY; without even the implied warranty of
    00013 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    00014 // GNU General Public License for more details.
    00015
    00016 // You should have received a copy of the GNU General Public License along
    00017 // with this library; see the file COPYING.  If not, write to the Free
    00018 // Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
    00019 // USA.
    00020
    00021 // As a special exception, you may use this file as part of a free software
    00022 // library without restriction.  Specifically, if other files instantiate
    00023 // templates or use macros or inline functions from this file, or you compile
    00024 // this file and link it with other files to produce an executable, this
    00025 // file does not by itself cause the resulting executable to be covered by
    00026 // the GNU General Public License.  This exception does not however
    00027 // invalidate any other reasons why the executable file might be covered by
    00028 // the GNU General Public License.
    00029
    00030 /*
    00031  *
    00032  * Copyright (c) 1994
    00033  * Hewlett-Packard Company
    00034  *
    00035  * Permission to use, copy, modify, distribute and sell this software
    00036  * and its documentation for any purpose is hereby granted without fee,
    00037  * provided that the above copyright notice appear in all copies and
    00038  * that both that copyright notice and this permission notice appear
    00039  * in supporting documentation.  Hewlett-Packard Company makes no
    00040  * representations about the suitability of this software for any
    00041  * purpose.  It is provided "as is" without express or implied warranty.
    00042  *
    00043  *
    00044  * Copyright (c) 1996,1997
    00045  * Silicon Graphics Computer Systems, Inc.
    00046  *
    00047  * Permission to use, copy, modify, distribute and sell this software
    00048  * and its documentation for any purpose is hereby granted without fee,
    00049  * provided that the above copyright notice appear in all copies and
    00050  * that both that copyright notice and this permission notice appear
    00051  * in supporting documentation.  Silicon Graphics makes no
    00052  * representations about the suitability of this software for any
    00053  * purpose.  It is provided "as is" without express or implied warranty.
    00054  */
    00055
    00056 /** @file stl_tempbuf.h
    00057  *  This is an internal header file, included by other library headers.
    00058  *  You should not attempt to use it directly.
    00059  */
    00060
    00061 #ifndef _TEMPBUF_H
    00062 #define _TEMPBUF_H 1
    00063
    00064 #include <memory>
    00065
    00066 namespace std
    00067 {
    00068   /**
    00069    *  @if maint
    00070    *  This class is used in two places: stl_algo.h and ext/memory,
    00071    *  where it is wrapped as the temporary_buffer class.  See
    00072    *  temporary_buffer docs for more notes.
    00073    *  @endif
    00074    */
    00075   template<typename _ForwardIterator, typename _Tp>
    00076     class _Temporary_buffer
    00077     {
    00078       // concept requirements
    00079       __glibcxx_class_requires(_ForwardIterator, _ForwardIteratorConcept)
    00080
    00081     public:
    00082       typedef _Tp         value_type;
    00083       typedef value_type* pointer;
    00084       typedef pointer     iterator;
    00085       typedef ptrdiff_t   size_type;
    00086
    00087     protected:
    00088       size_type  _M_original_len;
    00089       size_type  _M_len;
    00090       pointer    _M_buffer;
    00091
    00092       void
    00093       _M_initialize_buffer(const _Tp&, __true_type) { }
    00094
    00095       void
    00096       _M_initialize_buffer(const _Tp& val, __false_type)
    00097       { std::uninitialized_fill_n(_M_buffer, _M_len, val); }
    00098
    00099     public:
    00100       /// As per Table mumble.
    00101       size_type
    00102       size() const
    00103       { return _M_len; }
    00104
    00105       /// Returns the size requested by the constructor; may be >size().
    00106       size_type
    00107       requested_size() const
    00108       { return _M_original_len; }
    00109
    00110       /// As per Table mumble.
    00111       iterator
    00112       begin()
    00113       { return _M_buffer; }
    00114
    00115       /// As per Table mumble.
    00116       iterator
    00117       end()
    00118       { return _M_buffer + _M_len; }
    00119
    00120       /**
    00121        * Constructs a temporary buffer of a size somewhere between
    00122        * zero and the size of the given range.
    00123        */
    00124       _Temporary_buffer(_ForwardIterator __first, _ForwardIterator __last);
    00125
    00126       ~_Temporary_buffer()
    00127       {
    00128     std::_Destroy(_M_buffer, _M_buffer + _M_len);
    00129     std::return_temporary_buffer(_M_buffer);
    00130       }
    00131
    00132     private:
    00133       // Disable copy constructor and assignment operator.
    00134       _Temporary_buffer(const _Temporary_buffer&);
    00135
    00136       void
    00137       operator=(const _Temporary_buffer&);
    00138     };
    00139
    00140
    00141   template<typename _ForwardIterator, typename _Tp>
    00142     _Temporary_buffer<_ForwardIterator, _Tp>::
    00143     _Temporary_buffer(_ForwardIterator __first, _ForwardIterator __last)
    00144     : _M_original_len(std::distance(__first, __last)),
    00145       _M_len(0), _M_buffer(0)
    00146     {
    00147       // Workaround for a __type_traits bug in the pre-7.3 compiler.
    00148       typedef typename __type_traits<_Tp>::has_trivial_default_constructor
    00149           _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 } // namespace std
    00169
    00170 #endif /* _TEMPBUF_H */
    00171