include/stlport/stl/_iostream_string.h

   1 /*
   2  * Copyright (c) 2004
   3  * Francois Dumont
   4  *
   5  * This material is provided "as is", with absolutely no warranty expressed
   6  * or implied. Any use is at your own risk.
   7  *
   8  * Permission to use or copy this software for any purpose is hereby granted
   9  * without fee, provided the above notices are retained on all copies.
  10  * Permission to modify the code and to distribute modified code is granted,
  11  * provided the above notices are retained, and a notice that the code was
  12  * modified is included with the above copyright notice.
  13  *
  14  */
  15
  16  /*
  17   * This is an internal string for the STLport own iostream implementation.
  18   * The only diference rely on the allocator used to instanciate the basic_string.
  19   * Its goals is to improve performance limitating the number of dynamic allocation
  20   * that could occur when requesting a big float ouput for instance. This allocator
  21   * is not standard conformant as it has an internal state (the static buffer)
  22   */
  23
  24
  25 #ifndef _STLP_INTERNAL_IOSTREAM_STRING_H
  26 #define _STLP_INTERNAL_IOSTREAM_STRING_H
  27
  28 #ifndef _STLP_INTERNAL_ALLOC_H
  29 #  include <stl/_alloc.h>
  30 #endif /* _STLP_INTERNAL_ALLOC_H */
  31
  32 #ifndef _STLP_INTERNAL_STRING_H
  33 #  include <stl/_string.h>
  34 #endif /* _STLP_INTERNAL_STRING_H */
  35
  36 _STLP_BEGIN_NAMESPACE
  37
  38 _STLP_MOVE_TO_PRIV_NAMESPACE
  39
  40 template <class _CharT>
  41 class __iostring_allocator : public allocator<_CharT> {
  42 public:
  43   enum { _STR_SIZE = 256 };
  44
  45 private:
  46   enum { _BUF_SIZE = _STR_SIZE + 1 };
  47   typedef allocator<_CharT> _Base;
  48   _CharT _M_static_buf[_BUF_SIZE];
  49
  50 public:
  51   typedef typename _Base::size_type size_type;
  52   typedef typename _Base::pointer pointer;
  53 #if defined (_STLP_MEMBER_TEMPLATE_CLASSES)
  54   template <class _Tp1> struct rebind {
  55 #  if !defined (_STLP_MSVC) || (_STLP_MSVC >= 1300)
  56     typedef __iostring_allocator<_Tp1> other;
  57 #  else
  58     typedef _STLP_PRIV __iostring_allocator<_Tp1> other;
  59 #  endif
  60   };
  61 #endif
  62
  63   _CharT* allocate(size_type __n, const void* __ptr = 0) {
  64     if (__n > _BUF_SIZE) {
  65       return _Base::allocate(__n, __ptr);
  66     }
  67     return _M_static_buf;
  68   }
  69   void deallocate(pointer __p, size_type __n) {
  70     if (__p != _M_static_buf) _Base::deallocate(__p, __n);
  71   }
  72 };
  73
  74 #if defined (_STLP_DONT_SUPPORT_REBIND_MEMBER_TEMPLATE) || !defined (_STLP_MEMBER_TEMPLATES)
  75 /*
  76  * As the __iostring_allocator allocator will only be used in the basic_string implementation
  77  * we known that it is never going to be bound to another type that the one used to instantiate
  78  * the basic_string. This is why the associated __stl_alloc_rebind has only one template
  79  * parameter.
  80  */
  81 _STLP_MOVE_TO_STD_NAMESPACE
  82
  83 template <class _Tp>
  84 inline _STLP_PRIV __iostring_allocator<_Tp>& _STLP_CALL
  85 __stl_alloc_rebind(_STLP_PRIV __iostring_allocator<_Tp>& __a, const _Tp*)
  86 { return __a; }
  87 template <class _Tp>
  88 inline _STLP_PRIV __iostring_allocator<_Tp> _STLP_CALL
  89 __stl_alloc_create(const _STLP_PRIV __iostring_allocator<_Tp>&, const _Tp*)
  90 { return _STLP_PRIV __iostring_allocator<_Tp>(); }
  91
  92 _STLP_MOVE_TO_PRIV_NAMESPACE
  93 #endif /* _STLP_DONT_SUPPORT_REBIND_MEMBER_TEMPLATE */
  94
  95 #if !defined (_STLP_DEBUG)
  96 template <class _CharT>
  97 struct __basic_iostring : public basic_string<_CharT, char_traits<_CharT>, __iostring_allocator<_CharT> > {
  98   /*
  99    * A consequence of the non standard conformant allocator is that a string using it
 100    * must always be presized to the allocator static buffer size because the basic_string implementation
 101    * do not manage an allocator returning always the same memory adress as long as the
 102    * requested memory block size is under a certain value.
 103    */
 104   typedef __basic_iostring<_CharT> _Self;
 105   typedef basic_string<_CharT, char_traits<_CharT>, __iostring_allocator<_CharT> > _Base;
 106   typedef typename _Base::_Reserve_t _Reserve_t;
 107
 108   __basic_iostring() : _Base(_Reserve_t(), __iostring_allocator<_CharT>::_STR_SIZE)
 109   {}
 110
 111   _Self& operator=(const _CharT* __s) {
 112     _Base::operator=(__s);
 113     return *this;
 114   }
 115 };
 116
 117 typedef __basic_iostring<char> __iostring;
 118
 119 #  if !defined (_STLP_NO_WCHAR_T)
 120 typedef __basic_iostring<wchar_t> __iowstring;
 121 #  endif
 122
 123 #  define _STLP_BASIC_IOSTRING(_CharT) _STLP_PRIV __basic_iostring<_CharT>
 124
 125 #else
 126
 127 typedef string __iostring;
 128 #  if !defined (_STLP_NO_WCHAR_T)
 129 typedef wstring __iowstring;
 130 #  endif
 131
 132 #  define _STLP_BASIC_IOSTRING(_CharT) basic_string<_CharT, char_traits<_CharT>, allocator<_CharT> >
 133
 134 #endif
 135
 136 _STLP_MOVE_TO_STD_NAMESPACE
 137
 138 _STLP_END_NAMESPACE
 139
 140 #endif /* _STLP_INTERNAL_IOSTREAM_STRING_H */