_iterator_base.h

MONA是为数不多的C++语言编写的一个很小的操作系统

/*
 *
 * Copyright (c) 1994
 * Hewlett-Packard Company
 *
 * Copyright (c) 1996-1998
 * Silicon Graphics Computer Systems, Inc.
 *
 * Copyright (c) 1997
 * Moscow Center for SPARC Technology
 *
 * Copyright (c) 1999 
 * Boris Fomitchev
 *
 * This material is provided "as is", with absolutely no warranty expressed
 * or implied. Any use is at your own risk.
 *
 * Permission to use or copy this software for any purpose is hereby granted 
 * without fee, provided the above notices are retained on all copies.
 * Permission to modify the code and to distribute modified code is granted,
 * provided the above notices are retained, and a notice that the code was
 * modified is included with the above copyright notice.
 *
 */

/* NOTE: This is an internal header file, included by other STL headers.
 *   You should not attempt to use it directly.
 */

#ifndef _STLP_INTERNAL_ITERATOR_BASE_H
#define _STLP_INTERNAL_ITERATOR_BASE_H

#ifndef _STLP_CSTDDEF
///# include <cstddef>
#endif

# if defined  (_STLP_IMPORT_VENDOR_CSTD) && ! defined (_STLP_VENDOR_GLOBAL_CSTD)
_STLP_BEGIN_NAMESPACE  
using namespace _STLP_VENDOR_CSTD;
_STLP_END_NAMESPACE
#endif /* _STLP_IMPORT_VENDOR_CSTD */

#ifndef __TYPE_TRAITS_H
# include <stl/type_traits.h>
#endif

_STLP_BEGIN_NAMESPACE

struct input_iterator_tag {};
struct output_iterator_tag {};
struct forward_iterator_tag : public input_iterator_tag {};
struct bidirectional_iterator_tag : public forward_iterator_tag {};
struct random_access_iterator_tag : public bidirectional_iterator_tag {};


template <class _Category, class _Tp, __DFL_TMPL_PARAM(_Distance,ptrdiff_t),
          __DFL_TMPL_PARAM(_Pointer,_Tp*), __DFL_TMPL_PARAM(_Reference,_Tp&) >
struct iterator {
  typedef _Category  iterator_category;
  typedef _Tp        value_type;
  typedef _Distance  difference_type;
  typedef _Pointer   pointer;
  typedef _Reference reference;
};
_STLP_TEMPLATE_NULL
struct iterator<output_iterator_tag, void, void, void, void> {
  typedef output_iterator_tag  iterator_category;
#ifdef _STLP_CLASS_PARTIAL_SPECIALIZATION
  typedef void                value_type;
  typedef void                difference_type;
  typedef void                pointer;
  typedef void                reference;
#endif
};

# ifdef _STLP_USE_OLD_HP_ITERATOR_QUERIES
#  define _STLP_ITERATOR_CATEGORY(_It, _Tp) iterator_category(_It)
#  define _STLP_DISTANCE_TYPE(_It, _Tp)     distance_type(_It)
#  define _STLP_VALUE_TYPE(_It, _Tp)        value_type(_It)
# else
#  ifdef _STLP_CLASS_PARTIAL_SPECIALIZATION
#   define _STLP_VALUE_TYPE(_It, _Tp)        (typename iterator_traits< _Tp >::value_type*)0
#   define _STLP_DISTANCE_TYPE(_It, _Tp)     (typename iterator_traits< _Tp >::difference_type*)0
#   if defined (__BORLANDC__) || defined (__SUNPRO_CC) || ( defined (__MWERKS__) && (__MWERKS__ <= 0x2303)) || ( defined (__sgi) && defined (_COMPILER_VERSION)) || defined (__DMC__)
#    define _STLP_ITERATOR_CATEGORY(_It, _Tp) iterator_traits< _Tp >::iterator_category()
#   else
#    define _STLP_ITERATOR_CATEGORY(_It, _Tp) typename iterator_traits< _Tp >::iterator_category()
#   endif
#  else
#   define _STLP_ITERATOR_CATEGORY(_It, _Tp) __iterator_category(_It, _IsPtrType<_Tp>::_Ret())
#   define _STLP_DISTANCE_TYPE(_It, _Tp)     (ptrdiff_t*)0
#   define _STLP_VALUE_TYPE(_It, _Tp)        __value_type(_It, _IsPtrType<_Tp>::_Ret() )
#  endif
# endif

template <class _Iterator>
struct iterator_traits {
  typedef typename _Iterator::iterator_category iterator_category;
  typedef typename _Iterator::value_type        value_type;
  typedef typename _Iterator::difference_type   difference_type;
  typedef typename _Iterator::pointer           pointer;
  typedef typename _Iterator::reference         reference;
};


# if defined (_STLP_CLASS_PARTIAL_SPECIALIZATION) && ! defined (__SUNPRO_CC)
#  define _STLP_DIFFERENCE_TYPE(_Iterator) typename iterator_traits<_Iterator>::difference_type
# else
#  define _STLP_DIFFERENCE_TYPE(_Iterator) ptrdiff_t
# endif

# ifdef _STLP_CLASS_PARTIAL_SPECIALIZATION

// fbp : this order keeps gcc happy
template <class _Tp>
struct iterator_traits<const _Tp*> {
  typedef random_access_iterator_tag iterator_category;
  typedef _Tp                         value_type;
  typedef ptrdiff_t                   difference_type;
  typedef const _Tp*                  pointer;
  typedef const _Tp&                  reference;
};

template <class _Tp>
struct iterator_traits<_Tp*> {
  typedef random_access_iterator_tag iterator_category;
  typedef _Tp                         value_type;
  typedef ptrdiff_t                   difference_type;
  typedef _Tp*                        pointer;
  typedef _Tp&                        reference;
};

#  if defined (__BORLANDC__)
template <class _Tp>
struct iterator_traits<_Tp* const> {
  typedef random_access_iterator_tag iterator_category;
  typedef _Tp                         value_type;
  typedef ptrdiff_t                   difference_type;
  typedef const _Tp*                  pointer;
  typedef const _Tp&                  reference;
};
#  endif

# endif /* _STLP_CLASS_PARTIAL_SPECIALIZATION */


# if defined (_STLP_CLASS_PARTIAL_SPECIALIZATION) \
  || (defined (_STLP_SIMULATE_PARTIAL_SPEC_FOR_TYPE_TRAITS) && ! defined (_STLP_NO_ARROW_OPERATOR))
#  define _STLP_POINTERS_SPECIALIZE( _TpP )
#  define _STLP_DEFINE_ARROW_OPERATOR  pointer operator->() const { return &(operator*()); }
# else 
#  include <stl/_ptrs_specialize.h>
# endif

# ifndef _STLP_USE_OLD_HP_ITERATOR_QUERIES
// The overloaded functions iterator_category, distance_type, and
// value_type are not part of the C++ standard.  (They have been
// replaced by struct iterator_traits.)  They are included for
// backward compatibility with the HP STL.
// We introduce internal names for these functions.

#  ifdef  _STLP_CLASS_PARTIAL_SPECIALIZATION

template <class _Iter>
inline typename iterator_traits<_Iter>::iterator_category __iterator_category(const _Iter&) {
  typedef typename iterator_traits<_Iter>::iterator_category _Category;
  return _Category();
}

template <class _Iter>
inline typename iterator_traits<_Iter>::difference_type* __distance_type(const _Iter&) {
  typedef typename iterator_traits<_Iter>::difference_type _diff_type;
  return __STATIC_CAST(_diff_type*,0);
}

template <class _Iter>
inline typename iterator_traits<_Iter>::value_type* __value_type(const _Iter&) {
  typedef typename iterator_traits<_Iter>::value_type _value_type;
  return __STATIC_CAST(_value_type*,0);
}

# else

template <class _Iter>
inline random_access_iterator_tag 
__iterator_category(const _Iter&, const __true_type&) {
  return random_access_iterator_tag();
}

template <class _Iter>
inline _STLP_TYPENAME_ON_RETURN_TYPE iterator_traits<_Iter>::iterator_category
__iterator_category(const _Iter&, const __false_type&) {
  typedef typename iterator_traits<_Iter>::iterator_category _Category;
  return _Category();
}


template <class _Iter>
inline ptrdiff_t* _STLP_CALL __distance_type(const _Iter&) { return (ptrdiff_t*)(0); }

template <class _Iter>
inline _STLP_TYPENAME_ON_RETURN_TYPE iterator_traits<_Iter>::value_type* 
__value_type(const _Iter&, const __false_type&) {
  typedef typename iterator_traits<_Iter>::value_type _value_type;
  return __STATIC_CAST(_value_type*,0);
}

template <class _Tp>
inline _Tp*  
__value_type(const _Tp*, const __true_type&) {
  return __STATIC_CAST(_Tp*, 0);
}

# endif

#else /* old queries */
template <class _Category, class _Tp, class _Distance, class _Pointer, class _Reference>
inline _Category _STLP_CALL iterator_category(const iterator<_Category,_Tp,_Distance,_Pointer,_Reference>&) { return _Category(); }
template <class _Category, class _Tp, class _Distance, class _Pointer, class _Reference>
inline _Tp* _STLP_CALL value_type(const iterator<_Category,_Tp,_Distance,_Pointer,_Reference>&) { return (_Tp*)(0); }
template <class _Category, class _Tp, class _Distance, class _Pointer, class _Reference>
inline _Distance* _STLP_CALL distance_type(const iterator<_Category,_Tp,_Distance,_Pointer,_Reference>&) { return (_Distance*)(0); }
template <class _Tp>
inline random_access_iterator_tag _STLP_CALL iterator_category(const _Tp*) { return random_access_iterator_tag(); }
template <class _Tp>
inline _Tp* _STLP_CALL value_type(const _Tp*) { return (_Tp*)(0); }
template <class _Tp>
inline ptrdiff_t* _STLP_CALL distance_type(const _Tp*) { return (ptrdiff_t*)(0); }
#endif /* _STLP_USE_OLD_HP_ITERATOR_QUERIES */

# if ! defined (_STLP_NO_ANACHRONISMS)
// The base classes input_iterator, output_iterator, forward_iterator,