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/* |
* |
* Copyright (c) 1997 |
* Silicon Graphics Computer Systems, Inc. |
* |
* Permission to use, copy, modify, distribute and sell this software |
* and its documentation for any purpose is hereby granted without fee, |
* provided that the above copyright notice appear in all copies and |
* that both that copyright notice and this permission notice appear |
* in supporting documentation. Silicon Graphics makes no |
* representations about the suitability of this software for any |
* purpose. It is provided "as is" without express or implied warranty. |
*/ |
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#ifndef _CPP_BITS_TYPE_TRAITS_H |
#define _CPP_BITS_TYPE_TRAITS_H 1 |
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#pragma GCC system_header |
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#include <bits/c++config.h> |
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/* |
This header file provides a framework for allowing compile time dispatch |
based on type attributes. This is useful when writing template code. |
For example, when making a copy of an array of an unknown type, it helps |
to know if the type has a trivial copy constructor or not, to help decide |
if a memcpy can be used. |
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The class template __type_traits provides a series of typedefs each of |
which is either __true_type or __false_type. The argument to |
__type_traits can be any type. The typedefs within this template will |
attain their correct values by one of these means: |
1. The general instantiation contain conservative values which work |
for all types. |
2. Specializations may be declared to make distinctions between types. |
3. Some compilers (such as the Silicon Graphics N32 and N64 compilers) |
will automatically provide the appropriate specializations for all |
types. |
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EXAMPLE: |
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//Copy an array of elements which have non-trivial copy constructors |
template <class _Tp> void |
copy(_Tp* __source,_Tp* __destination,int __n,__false_type); |
//Copy an array of elements which have trivial copy constructors. Use memcpy. |
template <class _Tp> void |
copy(_Tp* __source,_Tp* __destination,int __n,__true_type); |
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//Copy an array of any type by using the most efficient copy mechanism |
template <class _Tp> inline void copy(_Tp* __source,_Tp* __destination,int __n) { |
copy(__source,__destination,__n, |
typename __type_traits<_Tp>::has_trivial_copy_constructor()); |
} |
*/ |
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template <bool _Truth> struct _Bool {}; |
typedef _Bool<true> __true_type; |
typedef _Bool<false> __false_type; |
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template <class _Tp> |
struct __type_traits { |
typedef __true_type this_dummy_member_must_be_first; |
/* Do not remove this member. It informs a compiler which |
automatically specializes __type_traits that this |
__type_traits template is special. It just makes sure that |
things work if an implementation is using a template |
called __type_traits for something unrelated. */ |
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/* The following restrictions should be observed for the sake of |
compilers which automatically produce type specific specializations |
of this class: |
- You may reorder the members below if you wish |
- You may remove any of the members below if you wish |
- You must not rename members without making the corresponding |
name change in the compiler |
- Members you add will be treated like regular members unless |
you add the appropriate support in the compiler. */ |
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typedef __false_type has_trivial_default_constructor; |
typedef __false_type has_trivial_copy_constructor; |
typedef __false_type has_trivial_assignment_operator; |
typedef __false_type has_trivial_destructor; |
typedef __false_type is_POD_type; |
}; |
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// Provide some specializations. |
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template<> struct __type_traits<bool> { |
typedef __true_type has_trivial_default_constructor; |
typedef __true_type has_trivial_copy_constructor; |
typedef __true_type has_trivial_assignment_operator; |
typedef __true_type has_trivial_destructor; |
typedef __true_type is_POD_type; |
}; |
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template<> struct __type_traits<char> { |
typedef __true_type has_trivial_default_constructor; |
typedef __true_type has_trivial_copy_constructor; |
typedef __true_type has_trivial_assignment_operator; |
typedef __true_type has_trivial_destructor; |
typedef __true_type is_POD_type; |
}; |
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template<> struct __type_traits<signed char> { |
typedef __true_type has_trivial_default_constructor; |
typedef __true_type has_trivial_copy_constructor; |
typedef __true_type has_trivial_assignment_operator; |
typedef __true_type has_trivial_destructor; |
typedef __true_type is_POD_type; |
}; |
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template<> struct __type_traits<unsigned char> { |
typedef __true_type has_trivial_default_constructor; |
typedef __true_type has_trivial_copy_constructor; |
typedef __true_type has_trivial_assignment_operator; |
typedef __true_type has_trivial_destructor; |
typedef __true_type is_POD_type; |
}; |
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template<> struct __type_traits<wchar_t> { |
typedef __true_type has_trivial_default_constructor; |
typedef __true_type has_trivial_copy_constructor; |
typedef __true_type has_trivial_assignment_operator; |
typedef __true_type has_trivial_destructor; |
typedef __true_type is_POD_type; |
}; |
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template<> struct __type_traits<short> { |
typedef __true_type has_trivial_default_constructor; |
typedef __true_type has_trivial_copy_constructor; |
typedef __true_type has_trivial_assignment_operator; |
typedef __true_type has_trivial_destructor; |
typedef __true_type is_POD_type; |
}; |
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template<> struct __type_traits<unsigned short> { |
typedef __true_type has_trivial_default_constructor; |
typedef __true_type has_trivial_copy_constructor; |
typedef __true_type has_trivial_assignment_operator; |
typedef __true_type has_trivial_destructor; |
typedef __true_type is_POD_type; |
}; |
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template<> struct __type_traits<int> { |
typedef __true_type has_trivial_default_constructor; |
typedef __true_type has_trivial_copy_constructor; |
typedef __true_type has_trivial_assignment_operator; |
typedef __true_type has_trivial_destructor; |
typedef __true_type is_POD_type; |
}; |
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template<> struct __type_traits<unsigned int> { |
typedef __true_type has_trivial_default_constructor; |
typedef __true_type has_trivial_copy_constructor; |
typedef __true_type has_trivial_assignment_operator; |
typedef __true_type has_trivial_destructor; |
typedef __true_type is_POD_type; |
}; |
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template<> struct __type_traits<long> { |
typedef __true_type has_trivial_default_constructor; |
typedef __true_type has_trivial_copy_constructor; |
typedef __true_type has_trivial_assignment_operator; |
typedef __true_type has_trivial_destructor; |
typedef __true_type is_POD_type; |
}; |
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template<> struct __type_traits<unsigned long> { |
typedef __true_type has_trivial_default_constructor; |
typedef __true_type has_trivial_copy_constructor; |
typedef __true_type has_trivial_assignment_operator; |
typedef __true_type has_trivial_destructor; |
typedef __true_type is_POD_type; |
}; |
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#ifdef _GLIBCPP_USE_LONG_LONG |
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template<> struct __type_traits<long long> { |
typedef __true_type has_trivial_default_constructor; |
typedef __true_type has_trivial_copy_constructor; |
typedef __true_type has_trivial_assignment_operator; |
typedef __true_type has_trivial_destructor; |
typedef __true_type is_POD_type; |
}; |
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template<> struct __type_traits<unsigned long long> { |
typedef __true_type has_trivial_default_constructor; |
typedef __true_type has_trivial_copy_constructor; |
typedef __true_type has_trivial_assignment_operator; |
typedef __true_type has_trivial_destructor; |
typedef __true_type is_POD_type; |
}; |
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#endif /* _GLIBCPP_USE_LONG_LONG */ |
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template<> struct __type_traits<float> { |
typedef __true_type has_trivial_default_constructor; |
typedef __true_type has_trivial_copy_constructor; |
typedef __true_type has_trivial_assignment_operator; |
typedef __true_type has_trivial_destructor; |
typedef __true_type is_POD_type; |
}; |
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template<> struct __type_traits<double> { |
typedef __true_type has_trivial_default_constructor; |
typedef __true_type has_trivial_copy_constructor; |
typedef __true_type has_trivial_assignment_operator; |
typedef __true_type has_trivial_destructor; |
typedef __true_type is_POD_type; |
}; |
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template<> struct __type_traits<long double> { |
typedef __true_type has_trivial_default_constructor; |
typedef __true_type has_trivial_copy_constructor; |
typedef __true_type has_trivial_assignment_operator; |
typedef __true_type has_trivial_destructor; |
typedef __true_type is_POD_type; |
}; |
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template <class _Tp> |
struct __type_traits<_Tp*> { |
typedef __true_type has_trivial_default_constructor; |
typedef __true_type has_trivial_copy_constructor; |
typedef __true_type has_trivial_assignment_operator; |
typedef __true_type has_trivial_destructor; |
typedef __true_type is_POD_type; |
}; |
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// The following could be written in terms of numeric_limits. |
// We're doing it separately to reduce the number of dependencies. |
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template <class _Tp> struct _Is_integer { |
typedef __false_type _Integral; |
}; |
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template<> struct _Is_integer<bool> { |
typedef __true_type _Integral; |
}; |
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template<> struct _Is_integer<char> { |
typedef __true_type _Integral; |
}; |
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template<> struct _Is_integer<signed char> { |
typedef __true_type _Integral; |
}; |
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template<> struct _Is_integer<unsigned char> { |
typedef __true_type _Integral; |
}; |
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template<> struct _Is_integer<wchar_t> { |
typedef __true_type _Integral; |
}; |
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template<> struct _Is_integer<short> { |
typedef __true_type _Integral; |
}; |
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template<> struct _Is_integer<unsigned short> { |
typedef __true_type _Integral; |
}; |
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template<> struct _Is_integer<int> { |
typedef __true_type _Integral; |
}; |
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template<> struct _Is_integer<unsigned int> { |
typedef __true_type _Integral; |
}; |
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template<> struct _Is_integer<long> { |
typedef __true_type _Integral; |
}; |
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template<> struct _Is_integer<unsigned long> { |
typedef __true_type _Integral; |
}; |
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#ifdef _GLIBCPP_USE_LONG_LONG |
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template<> struct _Is_integer<long long> { |
typedef __true_type _Integral; |
}; |
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template<> struct _Is_integer<unsigned long long> { |
typedef __true_type _Integral; |
}; |
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#endif /* _GLIBCPP_USE_LONG_LONG */ |
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template<typename _Tp> struct _Is_normal_iterator { |
typedef __false_type _Normal; |
}; |
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// Forward declaration hack, should really include this from somewhere. |
namespace std { |
template<typename _Iterator, typename _Container> class __normal_iterator; |
}; |
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template<typename _Iterator, typename _Container> |
struct _Is_normal_iterator< std::__normal_iterator<_Iterator, _Container> > { |
typedef __true_type _Normal; |
}; |
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#endif /* _CPP_BITS_TYPE_TRAITS_H */ |
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// Local Variables: |
// mode:C++ |
// End: |