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quickerNES/extern/phmap/parallel_hashmap/phmap_utils.h

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#if !defined(phmap_utils_h_guard_)
#define phmap_utils_h_guard_
// ---------------------------------------------------------------------------
// Copyright (c) 2019, Gregory Popovitch - greg7mdp@gmail.com
//
// minimal header providing phmap::HashState
//
// use as: phmap::HashState().combine(0, _first_name, _last_name, _age);
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// ---------------------------------------------------------------------------
#ifdef _MSC_VER
#pragma warning(push)
#pragma warning(disable : 4514) // unreferenced inline function has been removed
#pragma warning(disable : 4710) // function not inlined
#pragma warning(disable : 4711) // selected for automatic inline expansion
#endif
#include <cstdint>
#include <functional>
#include <tuple>
#include "phmap_bits.h"
// ---------------------------------------------------------------
// Absl forward declaration requires global scope.
// ---------------------------------------------------------------
#if defined(PHMAP_USE_ABSL_HASH) && !defined(phmap_fwd_decl_h_guard_) && !defined(ABSL_HASH_HASH_H_)
namespace absl { template <class T> struct Hash; };
#endif
namespace phmap
{
// ---------------------------------------------------------------
// ---------------------------------------------------------------
template<int n>
struct phmap_mix
{
inline size_t operator()(size_t) const;
};
template<>
struct phmap_mix<4>
{
inline size_t operator()(size_t a) const
{
static constexpr uint64_t kmul = 0xcc9e2d51UL;
// static constexpr uint64_t kmul = 0x3B9ACB93UL; // [greg] my own random prime
uint64_t l = a * kmul;
return static_cast<size_t>(l ^ (l >> 32));
}
};
#if defined(PHMAP_HAS_UMUL128)
template<>
struct phmap_mix<8>
{
// Very fast mixing (similar to Abseil)
inline size_t operator()(size_t a) const
{
static constexpr uint64_t k = 0xde5fb9d2630458e9ULL;
// static constexpr uint64_t k = 0x7C9D0BF0567102A5ULL; // [greg] my own random prime
uint64_t h;
uint64_t l = umul128(a, k, &h);
return static_cast<size_t>(h + l);
}
};
#else
template<>
struct phmap_mix<8>
{
inline size_t operator()(size_t a) const
{
a = (~a) + (a << 21); // a = (a << 21) - a - 1;
a = a ^ (a >> 24);
a = (a + (a << 3)) + (a << 8); // a * 265
a = a ^ (a >> 14);
a = (a + (a << 2)) + (a << 4); // a * 21
a = a ^ (a >> 28);
a = a + (a << 31);
return static_cast<size_t>(a);
}
};
#endif
// --------------------------------------------
template<int n>
struct fold_if_needed
{
inline size_t operator()(uint64_t) const;
};
template<>
struct fold_if_needed<4>
{
inline size_t operator()(uint64_t a) const
{
return static_cast<size_t>(a ^ (a >> 32));
}
};
template<>
struct fold_if_needed<8>
{
inline size_t operator()(uint64_t a) const
{
return static_cast<size_t>(a);
}
};
// ---------------------------------------------------------------
// see if class T has a hash_value() friend method
// ---------------------------------------------------------------
template<typename T>
struct has_hash_value
{
private:
typedef std::true_type yes;
typedef std::false_type no;
template<typename U> static auto test(int) -> decltype(hash_value(std::declval<const U&>()) == 1, yes());
template<typename> static no test(...);
public:
static constexpr bool value = std::is_same<decltype(test<T>(0)), yes>::value;
};
#if defined(PHMAP_USE_ABSL_HASH) && !defined(phmap_fwd_decl_h_guard_)
template <class T> using Hash = ::absl::Hash<T>;
#elif !defined(PHMAP_USE_ABSL_HASH)
// ---------------------------------------------------------------
// phmap::Hash
// ---------------------------------------------------------------
template <class T>
struct Hash
{
template <class U, typename std::enable_if<has_hash_value<U>::value, int>::type = 0>
size_t _hash(const T& val) const
{
return hash_value(val);
}
template <class U, typename std::enable_if<!has_hash_value<U>::value, int>::type = 0>
size_t _hash(const T& val) const
{
return std::hash<T>()(val);
}
inline size_t operator()(const T& val) const
{
return _hash<T>(val);
}
};
template <class T>
struct Hash<T *>
{
inline size_t operator()(const T *val) const noexcept
{
return static_cast<size_t>(reinterpret_cast<const uintptr_t>(val));
}
};
template<class ArgumentType, class ResultType>
struct phmap_unary_function
{
typedef ArgumentType argument_type;
typedef ResultType result_type;
};
template <>
struct Hash<bool> : public phmap_unary_function<bool, size_t>
{
inline size_t operator()(bool val) const noexcept
{ return static_cast<size_t>(val); }
};
template <>
struct Hash<char> : public phmap_unary_function<char, size_t>
{
inline size_t operator()(char val) const noexcept
{ return static_cast<size_t>(val); }
};
template <>
struct Hash<signed char> : public phmap_unary_function<signed char, size_t>
{
inline size_t operator()(signed char val) const noexcept
{ return static_cast<size_t>(val); }
};
template <>
struct Hash<unsigned char> : public phmap_unary_function<unsigned char, size_t>
{
inline size_t operator()(unsigned char val) const noexcept
{ return static_cast<size_t>(val); }
};
#ifdef PHMAP_HAS_NATIVE_WCHAR_T
template <>
struct Hash<wchar_t> : public phmap_unary_function<wchar_t, size_t>
{
inline size_t operator()(wchar_t val) const noexcept
{ return static_cast<size_t>(val); }
};
#endif
template <>
struct Hash<int16_t> : public phmap_unary_function<int16_t, size_t>
{
inline size_t operator()(int16_t val) const noexcept
{ return static_cast<size_t>(val); }
};
template <>
struct Hash<uint16_t> : public phmap_unary_function<uint16_t, size_t>
{
inline size_t operator()(uint16_t val) const noexcept
{ return static_cast<size_t>(val); }
};
template <>
struct Hash<int32_t> : public phmap_unary_function<int32_t, size_t>
{
inline size_t operator()(int32_t val) const noexcept
{ return static_cast<size_t>(val); }
};
template <>
struct Hash<uint32_t> : public phmap_unary_function<uint32_t, size_t>
{
inline size_t operator()(uint32_t val) const noexcept
{ return static_cast<size_t>(val); }
};
template <>
struct Hash<int64_t> : public phmap_unary_function<int64_t, size_t>
{
inline size_t operator()(int64_t val) const noexcept
{ return fold_if_needed<sizeof(size_t)>()(static_cast<uint64_t>(val)); }
};
template <>
struct Hash<uint64_t> : public phmap_unary_function<uint64_t, size_t>
{
inline size_t operator()(uint64_t val) const noexcept
{ return fold_if_needed<sizeof(size_t)>()(val); }
};
template <>
struct Hash<float> : public phmap_unary_function<float, size_t>
{
inline size_t operator()(float val) const noexcept
{
// -0.0 and 0.0 should return same hash
uint32_t *as_int = reinterpret_cast<uint32_t *>(&val);
return (val == 0) ? static_cast<size_t>(0) :
static_cast<size_t>(*as_int);
}
};
template <>
struct Hash<double> : public phmap_unary_function<double, size_t>
{
inline size_t operator()(double val) const noexcept
{
// -0.0 and 0.0 should return same hash
uint64_t *as_int = reinterpret_cast<uint64_t *>(&val);
return (val == 0) ? static_cast<size_t>(0) :
fold_if_needed<sizeof(size_t)>()(*as_int);
}
};
#endif
template <class H, int sz> struct Combiner
{
H operator()(H seed, size_t value);
};
template <class H> struct Combiner<H, 4>
{
H operator()(H seed, size_t value)
{
return seed ^ (value + 0x9e3779b9 + (seed << 6) + (seed >> 2));
}
};
template <class H> struct Combiner<H, 8>
{
H operator()(H seed, size_t value)
{
return seed ^ (value + size_t(0xc6a4a7935bd1e995) + (seed << 6) + (seed >> 2));
}
};
// define HashState to combine member hashes... see example below
// -----------------------------------------------------------------------------
template <typename H>
class HashStateBase {
public:
template <typename T, typename... Ts>
static H combine(H state, const T& value, const Ts&... values);
static H combine(H state) { return state; }
};
template <typename H>
template <typename T, typename... Ts>
H HashStateBase<H>::combine(H seed, const T& v, const Ts&... vs)
{
return HashStateBase<H>::combine(Combiner<H, sizeof(H)>()(
seed, phmap::Hash<T>()(v)),
vs...);
}
using HashState = HashStateBase<size_t>;
// -----------------------------------------------------------------------------
#if !defined(PHMAP_USE_ABSL_HASH)
// define Hash for std::pair
// -------------------------
template<class T1, class T2>
struct Hash<std::pair<T1, T2>> {
size_t operator()(std::pair<T1, T2> const& p) const noexcept {
return phmap::HashState().combine(phmap::Hash<T1>()(p.first), p.second);
}
};
// define Hash for std::tuple
// --------------------------
template<class... T>
struct Hash<std::tuple<T...>> {
size_t operator()(std::tuple<T...> const& t) const noexcept {
return _hash_helper(t);
}
private:
template<size_t I = 0, class ...P>
typename std::enable_if<I == sizeof...(P), size_t>::type
_hash_helper(const std::tuple<P...> &) const noexcept { return 0; }
template<size_t I = 0, class ...P>
typename std::enable_if<I < sizeof...(P), size_t>::type
_hash_helper(const std::tuple<P...> &t) const noexcept {
const auto &el = std::get<I>(t);
using el_type = typename std::remove_cv<typename std::remove_reference<decltype(el)>::type>::type;
return Combiner<size_t, sizeof(size_t)>()(
phmap::Hash<el_type>()(el), _hash_helper<I + 1>(t));
}
};
#endif
} // namespace phmap
#ifdef _MSC_VER
#pragma warning(pop)
#endif
#endif // phmap_utils_h_guard_
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