google_type_traits.h
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- // Copyright (c) 2006, Google Inc.
- // All rights reserved.
- //
- // Redistribution and use in source and binary forms, with or without
- // modification, are permitted provided that the following conditions are
- // met:
- //
- // * Redistributions of source code must retain the above copyright
- // notice, this list of conditions and the following disclaimer.
- // * Redistributions in binary form must reproduce the above
- // copyright notice, this list of conditions and the following disclaimer
- // in the documentation and/or other materials provided with the
- // distribution.
- // * Neither the name of Google Inc. nor the names of its
- // contributors may be used to endorse or promote products derived from
- // this software without specific prior written permission.
- //
- // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- // ----
- // Author: Matt Austern
- //
- // Define a small subset of tr1 type traits. The traits we define are:
- // is_integral
- // is_floating_point
- // is_pointer
- // is_pod
- // has_trivial_copy
- // has_trivial_assign
- // We can add more type traits as required.
- #ifndef BASE_TYPE_TRAITS_H__
- #define BASE_TYPE_TRAITS_H__
- #include "sparseconfig.h"
- #include <utility> // For pair
- _START_GOOGLE_NAMESPACE_
- // integral_constant, defined in tr1, is a wrapper for an integer
- // value. We don't really need this generality; we could get away
- // with hardcoding the integer type to bool. We use the fully
- // general integer_constant for compatibility with tr1.
- template<class T, T v>
- struct integral_constant {
- static const T value = v;
- typedef T value_type;
- typedef integral_constant<T, v> type;
- };
- template <class T, T v> const T integral_constant<T, v>::value;
- // Abbreviations: true_type and false_type are structs that represent
- // boolean true and false values.
- typedef integral_constant<bool, true> true_type;
- typedef integral_constant<bool, false> false_type;
- // is_integral is false except for the built-in integer types.
- template <class T> struct is_integral : false_type { };
- template<> struct is_integral<bool> : true_type { };
- template<> struct is_integral<char> : true_type { };
- template<> struct is_integral<unsigned char> : true_type { };
- template<> struct is_integral<signed char> : true_type { };
- #if defined(_MSC_VER)
- // wchar_t is not by default a distinct type from unsigned short in
- // Microsoft C.
- // See http://msdn2.microsoft.com/en-us/library/dh8che7s(VS.80).aspx
- template<> struct is_integral<__wchar_t> : true_type { };
- #else
- template<> struct is_integral<wchar_t> : true_type { };
- #endif
- template<> struct is_integral<short> : true_type { };
- template<> struct is_integral<unsigned short> : true_type { };
- template<> struct is_integral<int> : true_type { };
- template<> struct is_integral<unsigned int> : true_type { };
- template<> struct is_integral<long> : true_type { };
- template<> struct is_integral<unsigned long> : true_type { };
- #ifdef HAVE_LONG_LONG
- template<> struct is_integral<long long> : true_type { };
- template<> struct is_integral<unsigned long long> : true_type { };
- #endif
- // is_floating_point is false except for the built-in floating-point types.
- template <class T> struct is_floating_point : false_type { };
- template<> struct is_floating_point<float> : true_type { };
- template<> struct is_floating_point<double> : true_type { };
- template<> struct is_floating_point<long double> : true_type { };
- // is_pointer is false except for pointer types.
- template <class T> struct is_pointer : false_type { };
- template <class T> struct is_pointer<T*> : true_type { };
- // We can't get is_pod right without compiler help, so fail conservatively.
- // We will assume it's false except for arithmetic types and pointers,
- // and const versions thereof. Note that std::pair is not a POD.
- template <class T> struct is_pod
- : integral_constant<bool, (is_integral<T>::value ||
- is_floating_point<T>::value ||
- is_pointer<T>::value)> { };
- template <class T> struct is_pod<const T> : is_pod<T> { };
- // We can't get has_trivial_constructor right without compiler help, so
- // fail conservatively. We will assume it's false except for: (1) types
- // for which is_pod is true. (2) std::pair of types with trivial
- // constructors. (3) array of a type with a trivial constructor.
- // (4) const versions thereof.
- template <class T> struct has_trivial_constructor : is_pod<T> { };
- template <class T, class U> struct has_trivial_constructor<std::pair<T, U> >
- : integral_constant<bool,
- (has_trivial_constructor<T>::value &&
- has_trivial_constructor<U>::value)> { };
- template <class A, int N> struct has_trivial_constructor<A[N]>
- : has_trivial_constructor<A> { };
- template <class T> struct has_trivial_constructor<const T>
- : has_trivial_constructor<T> { };
- // We can't get has_trivial_copy right without compiler help, so fail
- // conservatively. We will assume it's false except for: (1) types
- // for which is_pod is true. (2) std::pair of types with trivial copy
- // constructors. (3) array of a type with a trivial copy constructor.
- // (4) const versions thereof.
- template <class T> struct has_trivial_copy : is_pod<T> { };
- template <class T, class U> struct has_trivial_copy<std::pair<T, U> >
- : integral_constant<bool,
- (has_trivial_copy<T>::value &&
- has_trivial_copy<U>::value)> { };
- template <class A, int N> struct has_trivial_copy<A[N]>
- : has_trivial_copy<A> { };
- template <class T> struct has_trivial_copy<const T> : has_trivial_copy<T> { };
- // We can't get has_trivial_assign right without compiler help, so fail
- // conservatively. We will assume it's false except for: (1) types
- // for which is_pod is true. (2) std::pair of types with trivial copy
- // constructors. (3) array of a type with a trivial assign constructor.
- template <class T> struct has_trivial_assign : is_pod<T> { };
- template <class T, class U> struct has_trivial_assign<std::pair<T, U> >
- : integral_constant<bool,
- (has_trivial_assign<T>::value &&
- has_trivial_assign<U>::value)> { };
- template <class A, int N> struct has_trivial_assign<A[N]>
- : has_trivial_assign<A> { };
- // We can't get has_trivial_destructor right without compiler help, so
- // fail conservatively. We will assume it's false except for: (1) types
- // for which is_pod is true. (2) std::pair of types with trivial
- // destructors. (3) array of a type with a trivial destructor.
- // (4) const versions thereof.
- template <class T> struct has_trivial_destructor : is_pod<T> { };
- template <class T, class U> struct has_trivial_destructor<std::pair<T, U> >
- : integral_constant<bool,
- (has_trivial_destructor<T>::value &&
- has_trivial_destructor<U>::value)> { };
- template <class A, int N> struct has_trivial_destructor<A[N]>
- : has_trivial_destructor<A> { };
- template <class T> struct has_trivial_destructor<const T>
- : has_trivial_destructor<T> { };
- // Specified by TR1 [4.7.1]
- template<typename T> struct remove_const { typedef T type; };
- template<typename T> struct remove_const<T const> { typedef T type; };
- // Specified by TR1 [4.7.2]
- template<typename T> struct remove_reference { typedef T type; };
- template<typename T> struct remove_reference<T&> { typedef T type; };
- // Specified by TR1 [4.7.4] Pointer modifications.
- template<typename T> struct remove_pointer { typedef T type; };
- template<typename T> struct remove_pointer<T*> { typedef T type; };
- template<typename T> struct remove_pointer<T* const> { typedef T type; };
- template<typename T> struct remove_pointer<T* volatile> { typedef T type; };
- template<typename T> struct remove_pointer<T* const volatile> {
- typedef T type; };
- _END_GOOGLE_NAMESPACE_
- #endif // BASE_TYPE_TRAITS_H__