headers/cpp/stl_tempbuf.h

   1 /*
   2  *
   3  * Copyright (c) 1994
   4  * Hewlett-Packard Company
   5  *
   6  * Permission to use, copy, modify, distribute and sell this software
   7  * and its documentation for any purpose is hereby granted without fee,
   8  * provided that the above copyright notice appear in all copies and
   9  * that both that copyright notice and this permission notice appear
  10  * in supporting documentation.  Hewlett-Packard Company makes no
  11  * representations about the suitability of this software for any
  12  * purpose.  It is provided "as is" without express or implied warranty.
  13  *
  14  *
  15  * Copyright (c) 1996,1997
  16  * Silicon Graphics Computer Systems, Inc.
  17  *
  18  * Permission to use, copy, modify, distribute and sell this software
  19  * and its documentation for any purpose is hereby granted without fee,
  20  * provided that the above copyright notice appear in all copies and
  21  * that both that copyright notice and this permission notice appear
  22  * in supporting documentation.  Silicon Graphics makes no
  23  * representations about the suitability of this software for any
  24  * purpose.  It is provided "as is" without express or implied warranty.
  25  */
  26
  27 /* NOTE: This is an internal header file, included by other STL headers.
  28  *   You should not attempt to use it directly.
  29  */
  30
  31 #ifndef __SGI_STL_INTERNAL_TEMPBUF_H
  32 #define __SGI_STL_INTERNAL_TEMPBUF_H
  33
  34
  35 __STL_BEGIN_NAMESPACE
  36
  37 template <class _Tp>
  38 pair<_Tp*, ptrdiff_t>
  39 __get_temporary_buffer(ptrdiff_t __len, _Tp*)
  40 {
  41   if (__len > ptrdiff_t(INT_MAX / sizeof(_Tp)))
  42     __len = INT_MAX / sizeof(_Tp);
  43
  44   while (__len > 0) {
  45     _Tp* __tmp = (_Tp*) malloc((size_t)__len * sizeof(_Tp));
  46     if (__tmp != 0)
  47       return pair<_Tp*, ptrdiff_t>(__tmp, __len);
  48     __len /= 2;
  49   }
  50
  51   return pair<_Tp*, ptrdiff_t>((_Tp*)0, 0);
  52 }
  53
  54 #ifdef __STL_EXPLICIT_FUNCTION_TMPL_ARGS
  55
  56 template <class _Tp>
  57 inline pair<_Tp*, ptrdiff_t> get_temporary_buffer(ptrdiff_t __len) {
  58   return __get_temporary_buffer(__len, (_Tp*) 0);
  59 }
  60
  61 #endif /* __STL_EXPLICIT_FUNCTION_TMPL_ARGS */
  62
  63 // This overload is not required by the standard; it is an extension.
  64 // It is supported for backward compatibility with the HP STL, and
  65 // because not all compilers support the language feature (explicit
  66 // function template arguments) that is required for the standard
  67 // version of get_temporary_buffer.
  68 template <class _Tp>
  69 inline pair<_Tp*, ptrdiff_t> get_temporary_buffer(ptrdiff_t __len, _Tp*) {
  70   return __get_temporary_buffer(__len, (_Tp*) 0);
  71 }
  72
  73 template <class _Tp>
  74 void return_temporary_buffer(_Tp* __p) {
  75   free(__p);
  76 }
  77
  78 template <class _ForwardIterator, class _Tp>
  79 class _Temporary_buffer {
  80 private:
  81   ptrdiff_t  _M_original_len;
  82   ptrdiff_t  _M_len;
  83   _Tp*       _M_buffer;
  84
  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   ptrdiff_t size() const { return _M_len; }
 107   ptrdiff_t requested_size() const { return _M_original_len; }
 108   _Tp* begin() { return _M_buffer; }
 109   _Tp* end() { return _M_buffer + _M_len; }
 110
 111   _Temporary_buffer(_ForwardIterator __first, _ForwardIterator __last) {
 112     typedef typename __type_traits<_Tp>::has_trivial_default_constructor
 113             _Trivial;
 114     __STL_TRY {
 115       _M_len = 0;
 116       distance(__first, __last, _M_len);
 117       _M_allocate_buffer();
 118       if (_M_len > 0)
 119         _M_initialize_buffer(*__first, _Trivial());
 120     }
 121     __STL_UNWIND(free(_M_buffer); _M_buffer = 0; _M_len = 0);
 122   }
 123
 124   ~_Temporary_buffer() {
 125     destroy(_M_buffer, _M_buffer + _M_len);
 126     free(_M_buffer);
 127   }
 128
 129 private:
 130   // Disable copy constructor and assignment operator.
 131   _Temporary_buffer(const _Temporary_buffer&) {}
 132   void operator=(const _Temporary_buffer&) {}
 133 };
 134
 135 // Class temporary_buffer is not part of the standard.  It is an extension.
 136
 137 template <class _ForwardIterator,
 138           class _Tp
 139 #ifdef __STL_CLASS_PARTIAL_SPECIALIZATION
 140                     = typename iterator_traits<_ForwardIterator>::value_type
 141 #endif /* __STL_CLASS_PARTIAL_SPECIALIZATION */
 142          >
 143 struct temporary_buffer : public _Temporary_buffer<_ForwardIterator, _Tp>
 144 {
 145   temporary_buffer(_ForwardIterator __first, _ForwardIterator __last)
 146     : _Temporary_buffer<_ForwardIterator, _Tp>(__first, __last) {}
 147   ~temporary_buffer() {}
 148 };
 149
 150 __STL_END_NAMESPACE
 151
 152 #endif /* __SGI_STL_INTERNAL_TEMPBUF_H */
 153
 154 // Local Variables:
 155 // mode:C++
 156 // End: