Maximilian Keßler
f0a496a8f0
This drastically reduces memory usage and also gains some performance. Since this is a drop-in replacement, there is essentially no downside in using this.
407 lines
11 KiB
C++
407 lines
11 KiB
C++
#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;
|
|
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;
|
|
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 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
|
|
|
|
#if defined(_MSC_VER)
|
|
# define PHMAP_HASH_ROTL32(x, r) _rotl(x,r)
|
|
#else
|
|
# define PHMAP_HASH_ROTL32(x, r) (x << r) | (x >> (32 - r))
|
|
#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 h1, size_t k1)
|
|
{
|
|
// Copyright 2005-2014 Daniel James.
|
|
// Distributed under the Boost Software License, Version 1.0. (See accompanying
|
|
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
|
|
|
|
const uint32_t c1 = 0xcc9e2d51;
|
|
const uint32_t c2 = 0x1b873593;
|
|
|
|
k1 *= c1;
|
|
k1 = PHMAP_HASH_ROTL32(k1,15);
|
|
k1 *= c2;
|
|
|
|
h1 ^= k1;
|
|
h1 = PHMAP_HASH_ROTL32(h1,13);
|
|
h1 = h1*5+0xe6546b64;
|
|
|
|
return h1;
|
|
}
|
|
};
|
|
|
|
template <class H> struct Combiner<H, 8>
|
|
{
|
|
H operator()(H h, size_t k)
|
|
{
|
|
// Copyright 2005-2014 Daniel James.
|
|
// Distributed under the Boost Software License, Version 1.0. (See accompanying
|
|
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
|
|
const uint64_t m = (uint64_t(0xc6a4a793) << 32) + 0x5bd1e995;
|
|
const int r = 47;
|
|
|
|
k *= m;
|
|
k ^= k >> r;
|
|
k *= m;
|
|
|
|
h ^= k;
|
|
h *= m;
|
|
|
|
// Completely arbitrary number, to prevent 0's
|
|
// from hashing to 0.
|
|
h += 0xe6546b64;
|
|
|
|
return h;
|
|
}
|
|
};
|
|
|
|
// 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 {
|
|
size_t seed = 0;
|
|
return _hash_helper(seed, t);
|
|
}
|
|
|
|
private:
|
|
template<size_t I = 0, class TUP>
|
|
typename std::enable_if<I == std::tuple_size<TUP>::value, size_t>::type
|
|
_hash_helper(size_t seed, const TUP &) const noexcept { return seed; }
|
|
|
|
template<size_t I = 0, class TUP>
|
|
typename std::enable_if<I < std::tuple_size<TUP>::value, size_t>::type
|
|
_hash_helper(size_t seed, const TUP &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;
|
|
seed = Combiner<size_t, sizeof(size_t)>()(seed, phmap::Hash<el_type>()(el));
|
|
return _hash_helper<I + 1>(seed, t);
|
|
}
|
|
};
|
|
|
|
|
|
#endif
|
|
|
|
|
|
} // namespace phmap
|
|
|
|
#ifdef _MSC_VER
|
|
#pragma warning(pop)
|
|
#endif
|
|
|
|
#endif // phmap_utils_h_guard_
|