--- /dev/null
+// functional_hash.h header -*- C++ -*-
+
+// Copyright (C) 2007, 2008, 2009, 2010, 2011 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 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// 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.
+
+// 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.
+ * Do not attempt to use it directly. @headername{functional}
+ */
+
+#ifndef _FUNCTIONAL_HASH_H
+#define _FUNCTIONAL_HASH_H 1
+
+#pragma GCC system_header
+
+#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;
+ typedef _Arg argument_type;
+ };
+
+ /// Primary class template hash.
+ template<typename _Tp>
+ struct hash : public __hash_base<size_t, _Tp>
+ {
+ static_assert(sizeof(_Tp) < 0,
+ "std::hash is not specialized for this type");
+ size_t operator()(const _Tp&) const noexcept;
+ };
+
+ /// 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)
+
+ /// 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)
+
+#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); }
+ };
+
+ 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); }
+
+ 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;
+ };
+
+ // @} group hashes
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif // _FUNCTIONAL_HASH_H
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