libstdc++-v3/include/bits/stl_tempbuf.h

   1 // Temporary buffer implementation -*- C++ -*-
   2
   3 // Copyright (C) 2001, 2002 Free Software Foundation, Inc.
   4 //
   5 // This file is part of the GNU ISO C++ Library.  This library is free
   6 // software; you can redistribute it and/or modify it under the
   7 // terms of the GNU General Public License as published by the
   8 // Free Software Foundation; either version 2, or (at your option)
   9 // any later version.
  10
  11 // This library is distributed in the hope that it will be useful,
  12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 // GNU General Public License for more details.
  15
  16 // You should have received a copy of the GNU General Public License along
  17 // with this library; see the file COPYING.  If not, write to the Free
  18 // Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
  19 // USA.
  20
  21 // As a special exception, you may use this file as part of a free software
  22 // library without restriction.  Specifically, if other files instantiate
  23 // templates or use macros or inline functions from this file, or you compile
  24 // this file and link it with other files to produce an executable, this
  25 // file does not by itself cause the resulting executable to be covered by
  26 // the GNU General Public License.  This exception does not however
  27 // invalidate any other reasons why the executable file might be covered by
  28 // the GNU General Public License.
  29
  30 /*
  31  *
  32  * Copyright (c) 1994
  33  * Hewlett-Packard Company
  34  *
  35  * Permission to use, copy, modify, distribute and sell this software
  36  * and its documentation for any purpose is hereby granted without fee,
  37  * provided that the above copyright notice appear in all copies and
  38  * that both that copyright notice and this permission notice appear
  39  * in supporting documentation.  Hewlett-Packard Company makes no
  40  * representations about the suitability of this software for any
  41  * purpose.  It is provided "as is" without express or implied warranty.
  42  *
  43  *
  44  * Copyright (c) 1996,1997
  45  * Silicon Graphics Computer Systems, Inc.
  46  *
  47  * Permission to use, copy, modify, distribute and sell this software
  48  * and its documentation for any purpose is hereby granted without fee,
  49  * provided that the above copyright notice appear in all copies and
  50  * that both that copyright notice and this permission notice appear
  51  * in supporting documentation.  Silicon Graphics makes no
  52  * representations about the suitability of this software for any
  53  * purpose.  It is provided "as is" without express or implied warranty.
  54  */
  55
  56 /** @file stl_tempbuf.h
  57  *  This is an internal header file, included by other library headers.
  58  *  You should not attempt to use it directly.
  59  */
  60
  61 #ifndef __GLIBCPP_INTERNAL_TEMPBUF_H
  62 #define __GLIBCPP_INTERNAL_TEMPBUF_H
  63
  64 namespace std
  65 {
  66
  67 /**
  68  *  @maint
  69  *  This class is used in two places:  stl_algo.h and ext/memory, where it
  70  *  is wrapped as the temporary_buffer class.  See temporary_buffer docs for
  71  *  more notes.
  72  *  @endmaint
  73 */
  74 template <class _ForwardIterator, class _Tp>
  75   class _Temporary_buffer
  76 {
  77   // concept requirements
  78   __glibcpp_class_requires(_ForwardIterator, _ForwardIteratorConcept)
  79
  80   ptrdiff_t  _M_original_len;
  81   ptrdiff_t  _M_len;
  82   _Tp*       _M_buffer;
  83
  84   // this is basically get_temporary_buffer() all over again
  85   void _M_allocate_buffer() {
  86     _M_original_len = _M_len;
  87     _M_buffer = 0;
  88
  89     if (_M_len > (ptrdiff_t)(INT_MAX / sizeof(_Tp)))
  90       _M_len = INT_MAX / sizeof(_Tp);
  91
  92     while (_M_len > 0) {
  93       _M_buffer = (_Tp*) malloc(_M_len * sizeof(_Tp));
  94       if (_M_buffer)
  95         break;
  96       _M_len /= 2;
  97     }
  98   }
  99
 100   void _M_initialize_buffer(const _Tp&, __true_type) {}
 101   void _M_initialize_buffer(const _Tp& val, __false_type) {
 102     uninitialized_fill_n(_M_buffer, _M_len, val);
 103   }
 104
 105 public:
 106   /// As per Table mumble.
 107   ptrdiff_t size() const { return _M_len; }
 108   /// Returns the size requested by the constructor; may be >size().
 109   ptrdiff_t requested_size() const { return _M_original_len; }
 110   /// As per Table mumble.
 111   _Tp* begin() { return _M_buffer; }
 112   /// As per Table mumble.
 113   _Tp* end() { return _M_buffer + _M_len; }
 114
 115   _Temporary_buffer(_ForwardIterator __first, _ForwardIterator __last) {
 116     // Workaround for a __type_traits bug in the pre-7.3 compiler.
 117     typedef typename __type_traits<_Tp>::has_trivial_default_constructor
 118             _Trivial;
 119
 120     try {
 121       _M_len = distance(__first, __last);
 122       _M_allocate_buffer();
 123       if (_M_len > 0)
 124         _M_initialize_buffer(*__first, _Trivial());
 125     }
 126     catch(...)
 127       {
 128         free(_M_buffer);
 129         _M_buffer = 0;
 130         _M_len = 0;
 131         __throw_exception_again;
 132       }
 133   }
 134
 135   ~_Temporary_buffer() {
 136     _Destroy(_M_buffer, _M_buffer + _M_len);
 137     free(_M_buffer);
 138   }
 139
 140 private:
 141   // Disable copy constructor and assignment operator.
 142   _Temporary_buffer(const _Temporary_buffer&) {}
 143   void operator=(const _Temporary_buffer&) {}
 144 };
 145
 146 } // namespace std
 147
 148 #endif /* __GLIBCPP_INTERNAL_TEMPBUF_H */
 149