// functional_hash.h header -*- C++ -*-
-// Copyright (C) 2007 Free Software Foundation, Inc.
+// Copyright (C) 2007-2020 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
-// Free Software Foundation; either version 2, or (at your option)
+// Free Software Foundation; either version 3, or (at your option)
// any later version.
// This library is distributed in the hope that it will be useful,
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
-// You should have received a copy of the GNU General Public License
-// along with this library; see the file COPYING. If not, write to
-// the Free Software Foundation, 51 Franklin Street, Fifth Floor,
-// Boston, MA 02110-1301, USA.
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
-// As a special exception, you may use this file as part of a free software
-// library without restriction. Specifically, if other files instantiate
-// templates or use macros or inline functions from this file, or you compile
-// this file and link it with other files to produce an executable, this
-// file does not by itself cause the resulting executable to be covered by
-// the GNU General Public License. This exception does not however
-// invalidate any other reasons why the executable file might be covered by
-// the GNU General Public License.
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
+// <http://www.gnu.org/licenses/>.
/** @file bits/functional_hash.h
* This is an internal header file, included by other library headers.
- * You should not attempt to use it directly.
+ * Do not attempt to use it directly. @headername{functional}
*/
#ifndef _FUNCTIONAL_HASH_H
#pragma GCC system_header
-#ifndef __GXX_EXPERIMENTAL_CXX0X__
-# include <c++0x_warning.h>
+#include <bits/hash_bytes.h>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+ /** @defgroup hashes Hashes
+ * @ingroup functors
+ *
+ * Hashing functors taking a variable type and returning a @c std::size_t.
+ *
+ * @{
+ */
+
+ template<typename _Result, typename _Arg>
+ struct __hash_base
+ {
+ typedef _Result result_type _GLIBCXX17_DEPRECATED;
+ typedef _Arg argument_type _GLIBCXX17_DEPRECATED;
+ };
+
+ /// Primary class template hash.
+ template<typename _Tp>
+ struct hash;
+
+ template<typename _Tp, typename = void>
+ struct __poison_hash
+ {
+ static constexpr bool __enable_hash_call = false;
+ private:
+ // Private rather than deleted to be non-trivially-copyable.
+ __poison_hash(__poison_hash&&);
+ ~__poison_hash();
+ };
+
+ template<typename _Tp>
+ struct __poison_hash<_Tp, __void_t<decltype(hash<_Tp>()(declval<_Tp>()))>>
+ {
+ static constexpr bool __enable_hash_call = true;
+ };
+
+ // Helper struct for SFINAE-poisoning non-enum types.
+ template<typename _Tp, bool = is_enum<_Tp>::value>
+ struct __hash_enum
+ {
+ private:
+ // Private rather than deleted to be non-trivially-copyable.
+ __hash_enum(__hash_enum&&);
+ ~__hash_enum();
+ };
+
+ // Helper struct for hash with enum types.
+ template<typename _Tp>
+ struct __hash_enum<_Tp, true> : public __hash_base<size_t, _Tp>
+ {
+ size_t
+ operator()(_Tp __val) const noexcept
+ {
+ using __type = typename underlying_type<_Tp>::type;
+ return hash<__type>{}(static_cast<__type>(__val));
+ }
+ };
+
+ /// Primary class template hash, usable for enum types only.
+ // Use with non-enum types still SFINAES.
+ template<typename _Tp>
+ struct hash : __hash_enum<_Tp>
+ { };
+
+ /// Partial specializations for pointer types.
+ template<typename _Tp>
+ struct hash<_Tp*> : public __hash_base<size_t, _Tp*>
+ {
+ size_t
+ operator()(_Tp* __p) const noexcept
+ { return reinterpret_cast<size_t>(__p); }
+ };
+
+ // Explicit specializations for integer types.
+#define _Cxx_hashtable_define_trivial_hash(_Tp) \
+ template<> \
+ struct hash<_Tp> : public __hash_base<size_t, _Tp> \
+ { \
+ size_t \
+ operator()(_Tp __val) const noexcept \
+ { return static_cast<size_t>(__val); } \
+ };
+
+ /// Explicit specialization for bool.
+ _Cxx_hashtable_define_trivial_hash(bool)
+
+ /// Explicit specialization for char.
+ _Cxx_hashtable_define_trivial_hash(char)
+
+ /// Explicit specialization for signed char.
+ _Cxx_hashtable_define_trivial_hash(signed char)
+
+ /// Explicit specialization for unsigned char.
+ _Cxx_hashtable_define_trivial_hash(unsigned char)
+
+ /// Explicit specialization for wchar_t.
+ _Cxx_hashtable_define_trivial_hash(wchar_t)
+
+#ifdef _GLIBCXX_USE_CHAR8_T
+ /// Explicit specialization for char8_t.
+ _Cxx_hashtable_define_trivial_hash(char8_t)
#endif
-#if defined(_GLIBCXX_INCLUDE_AS_TR1)
-# error C++0x header cannot be included from TR1 header
+ /// Explicit specialization for char16_t.
+ _Cxx_hashtable_define_trivial_hash(char16_t)
+
+ /// Explicit specialization for char32_t.
+ _Cxx_hashtable_define_trivial_hash(char32_t)
+
+ /// Explicit specialization for short.
+ _Cxx_hashtable_define_trivial_hash(short)
+
+ /// Explicit specialization for int.
+ _Cxx_hashtable_define_trivial_hash(int)
+
+ /// Explicit specialization for long.
+ _Cxx_hashtable_define_trivial_hash(long)
+
+ /// Explicit specialization for long long.
+ _Cxx_hashtable_define_trivial_hash(long long)
+
+ /// Explicit specialization for unsigned short.
+ _Cxx_hashtable_define_trivial_hash(unsigned short)
+
+ /// Explicit specialization for unsigned int.
+ _Cxx_hashtable_define_trivial_hash(unsigned int)
+
+ /// Explicit specialization for unsigned long.
+ _Cxx_hashtable_define_trivial_hash(unsigned long)
+
+ /// Explicit specialization for unsigned long long.
+ _Cxx_hashtable_define_trivial_hash(unsigned long long)
+
+#ifdef __GLIBCXX_TYPE_INT_N_0
+ _Cxx_hashtable_define_trivial_hash(__GLIBCXX_TYPE_INT_N_0)
+ _Cxx_hashtable_define_trivial_hash(__GLIBCXX_TYPE_INT_N_0 unsigned)
+#endif
+#ifdef __GLIBCXX_TYPE_INT_N_1
+ _Cxx_hashtable_define_trivial_hash(__GLIBCXX_TYPE_INT_N_1)
+ _Cxx_hashtable_define_trivial_hash(__GLIBCXX_TYPE_INT_N_1 unsigned)
+#endif
+#ifdef __GLIBCXX_TYPE_INT_N_2
+ _Cxx_hashtable_define_trivial_hash(__GLIBCXX_TYPE_INT_N_2)
+ _Cxx_hashtable_define_trivial_hash(__GLIBCXX_TYPE_INT_N_2 unsigned)
#endif
+#ifdef __GLIBCXX_TYPE_INT_N_3
+ _Cxx_hashtable_define_trivial_hash(__GLIBCXX_TYPE_INT_N_3)
+ _Cxx_hashtable_define_trivial_hash(__GLIBCXX_TYPE_INT_N_3 unsigned)
+#endif
+
+#undef _Cxx_hashtable_define_trivial_hash
+
+ struct _Hash_impl
+ {
+ static size_t
+ hash(const void* __ptr, size_t __clength,
+ size_t __seed = static_cast<size_t>(0xc70f6907UL))
+ { return _Hash_bytes(__ptr, __clength, __seed); }
+
+ template<typename _Tp>
+ static size_t
+ hash(const _Tp& __val)
+ { return hash(&__val, sizeof(__val)); }
+
+ template<typename _Tp>
+ static size_t
+ __hash_combine(const _Tp& __val, size_t __hash)
+ { return hash(&__val, sizeof(__val), __hash); }
+ };
+
+ // A hash function similar to FNV-1a (see PR59406 for how it differs).
+ struct _Fnv_hash_impl
+ {
+ static size_t
+ hash(const void* __ptr, size_t __clength,
+ size_t __seed = static_cast<size_t>(2166136261UL))
+ { return _Fnv_hash_bytes(__ptr, __clength, __seed); }
-#include <ext/numeric_traits.h>
-
-#if defined(_GLIBCXX_INCLUDE_AS_CXX0X)
-# include <tr1_impl/functional_hash.h>
-#else
-# define _GLIBCXX_INCLUDE_AS_CXX0X
-# define _GLIBCXX_BEGIN_NAMESPACE_TR1
-# define _GLIBCXX_END_NAMESPACE_TR1
-# define _GLIBCXX_TR1
-# include <tr1_impl/functional_hash.h>
-# undef _GLIBCXX_TR1
-# undef _GLIBCXX_END_NAMESPACE_TR1
-# undef _GLIBCXX_BEGIN_NAMESPACE_TR1
-# undef _GLIBCXX_INCLUDE_AS_CXX0X
+ template<typename _Tp>
+ static size_t
+ hash(const _Tp& __val)
+ { return hash(&__val, sizeof(__val)); }
+
+ template<typename _Tp>
+ static size_t
+ __hash_combine(const _Tp& __val, size_t __hash)
+ { return hash(&__val, sizeof(__val), __hash); }
+ };
+
+ /// Specialization for float.
+ template<>
+ struct hash<float> : public __hash_base<size_t, float>
+ {
+ size_t
+ operator()(float __val) const noexcept
+ {
+ // 0 and -0 both hash to zero.
+ return __val != 0.0f ? std::_Hash_impl::hash(__val) : 0;
+ }
+ };
+
+ /// Specialization for double.
+ template<>
+ struct hash<double> : public __hash_base<size_t, double>
+ {
+ size_t
+ operator()(double __val) const noexcept
+ {
+ // 0 and -0 both hash to zero.
+ return __val != 0.0 ? std::_Hash_impl::hash(__val) : 0;
+ }
+ };
+
+ /// Specialization for long double.
+ template<>
+ struct hash<long double>
+ : public __hash_base<size_t, long double>
+ {
+ _GLIBCXX_PURE size_t
+ operator()(long double __val) const noexcept;
+ };
+
+#if __cplusplus >= 201703L
+ template<>
+ struct hash<nullptr_t> : public __hash_base<size_t, nullptr_t>
+ {
+ size_t
+ operator()(nullptr_t) const noexcept
+ { return 0; }
+ };
#endif
+ // @} group hashes
-namespace std
-{
- struct error_code;
+ // Hint about performance of hash functor. If not fast the hash-based
+ // containers will cache the hash code.
+ // Default behavior is to consider that hashers are fast unless specified
+ // otherwise.
+ template<typename _Hash>
+ struct __is_fast_hash : public std::true_type
+ { };
template<>
- size_t
- hash<error_code>::operator()(error_code) const;
-}
+ struct __is_fast_hash<hash<long double>> : public std::false_type
+ { };
-#endif // _FUNCTIONAL_HASH_H
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+#endif // _FUNCTIONAL_HASH_H
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