Restructured folders: examples, benchmarks, tests into misc folder.

1 files changed, 1876 insertions, 0 deletions

diff --git a/misc/benchmarks/external/emhash/hash_table7.hpp b/misc/benchmarks/external/emhash/hash_table7.hpp
new file mode 100644
index 00000000..fdc33fe1
--- /dev/null
+++ b/misc/benchmarks/external/emhash/hash_table7.hpp
@@ -0,0 +1,1876 @@
+// emhash7::HashMap for C++11/14/17
+// version 2.2.3
+// https://github.com/ktprime/ktprime/blob/master/hash_table7.hpp
+//
+// Licensed under the MIT License <http://opensource.org/licenses/MIT>.
+// SPDX-License-Identifier: MIT
+// Copyright (c) 2019-2022 Huang Yuanbing & bailuzhou AT 163.com
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE
+
+// From
+// NUMBER OF PROBES / LOOKUP       Successful            Unsuccessful
+// Quadratic collision resolution  1 - ln(1-L) - L/2     1/(1-L) - L - ln(1-L)
+// Linear collision resolution     [1+1/(1-L)]/2         [1+1/(1-L)2]/2
+// separator chain resolution      1 + L / 2             exp(-L) + L
+
+// -- enlarge_factor --           0.10  0.50  0.60  0.75  0.80  0.90  0.99
+// QUADRATIC COLLISION RES.
+//    probes/successful lookup    1.05  1.44  1.62  2.01  2.21  2.85  5.11
+//    probes/unsuccessful lookup  1.11  2.19  2.82  4.64  5.81  11.4  103.6
+// LINEAR COLLISION RES.
+//    probes/successful lookup    1.06  1.5   1.75  2.5   3.0   5.5   50.5
+//    probes/unsuccessful lookup  1.12  2.5   3.6   8.5   13.0  50.0
+// SEPARATE CHAN RES.
+//    probes/successful lookup    1.05  1.25  1.3   1.25  1.4   1.45  1.50
+//    probes/unsuccessful lookup  1.00  1.11  1.15  1.22  1.25  1.31  1.37
+//    clacul/unsuccessful lookup  1.01  1.25  1.36, 1.56, 1.64, 1.81, 1.97
+
+/****************
+    under random hashCodes, the frequency of nodes in bins follows a Poisson
+distribution(http://en.wikipedia.org/wiki/Poisson_distribution) with a parameter of about 0.5
+on average for the default resizing threshold of 0.75, although with a large variance because
+of resizing granularity. Ignoring variance, the expected occurrences of list size k are
+(exp(-0.5) * pow(0.5, k)/factorial(k)). The first values are:
+0: 0.60653066
+1: 0.30326533
+2: 0.07581633
+3: 0.01263606
+4: 0.00157952
+5: 0.00015795
+6: 0.00001316
+7: 0.00000094
+8: 0.00000006
+
+  ============== buckets size ration ========
+    1   1543981  0.36884964|0.36787944  36.885
+    2    768655  0.36725597|0.36787944  73.611
+    3    256236  0.18364065|0.18393972  91.975
+    4     64126  0.06127757|0.06131324  98.102
+    5     12907  0.01541710|0.01532831  99.644
+    6      2050  0.00293841|0.00306566  99.938
+    7       310  0.00051840|0.00051094  99.990
+    8        49  0.00009365|0.00007299  99.999
+    9         4  0.00000860|0.00000913  100.000
+========== collision miss ration ===========
+  _num_filled aver_size k.v size_kv = 4185936, 1.58, x.x 24
+  collision,possion,cache_miss hit_find|hit_miss, load_factor = 36.73%,36.74%,31.31%  1.50|2.00, 1.00
+============== buckets size ration ========
+*******************************************************/
+
+#pragma once
+
+#include <cstring>
+#include <string>
+#include <cmath>
+#include <cstdlib>
+#include <type_traits>
+#include <cassert>
+#include <utility>
+#include <cstdint>
+#include <functional>
+#include <iterator>
+#include <algorithm>
+
+#if EMH_WY_HASH
+    #include "wyhash.h"
+#endif
+
+#ifdef EMH_KEY
+    #undef  EMH_KEY
+    #undef  EMH_VAL
+    #undef  EMH_PKV
+    #undef  EMH_NEW
+    #undef  EMH_SET
+    #undef  EMH_BUCKET
+    #undef  EMH_EMPTY
+#endif
+
+// likely/unlikely
+#if (__GNUC__ >= 4 || __clang__)
+#    define EMH_LIKELY(condition)   __builtin_expect(condition, 1)
+#    define EMH_UNLIKELY(condition) __builtin_expect(condition, 0)
+#else
+#    define EMH_LIKELY(condition)   condition
+#    define EMH_UNLIKELY(condition) condition
+#endif
+
+#ifndef EMH_BUCKET_INDEX
+    #define EMH_BUCKET_INDEX 1
+#endif
+
+#if EMH_BUCKET_INDEX == 0
+    #define EMH_KEY(p,n)     p[n].second.first
+    #define EMH_VAL(p,n)     p[n].second.second
+    #define EMH_BUCKET(p,n)  p[n].first
+    #define EMH_PKV(p,n)     p[n].second
+    #define EMH_NEW(key, val, bucket)\
+            new(_pairs + bucket) PairT(bucket, value_type(key, val));\
+            _num_filled ++;  EMH_SET(bucket)
+#elif EMH_BUCKET_INDEX == 2
+    #define EMH_KEY(p,n)     p[n].first.first
+    #define EMH_VAL(p,n)     p[n].first.second
+    #define EMH_BUCKET(p,n)  p[n].second
+    #define EMH_PKV(p,n)     p[n].first
+    #define EMH_NEW(key, val, bucket)\
+            new(_pairs + bucket) PairT(value_type(key, val), bucket);\
+            _num_filled ++;  EMH_SET(bucket)
+#else
+    #define EMH_KEY(p,n)     p[n].first
+    #define EMH_VAL(p,n)     p[n].second
+    #define EMH_BUCKET(p,n)  p[n].bucket
+    #define EMH_PKV(p,n)     p[n]
+    #define EMH_NEW(key, val, bucket)\
+            new(_pairs + bucket) PairT(key, val, bucket);\
+            _num_filled ++; EMH_SET(bucket)
+#endif
+
+#define EMH_MASK(bucket)               1 << (bucket % MASK_BIT)
+#define EMH_SET(bucket)                _bitmask[bucket / MASK_BIT] &= ~(EMH_MASK(bucket))
+#define EMH_CLS(bucket)                _bitmask[bucket / MASK_BIT] |= EMH_MASK(bucket)
+#define EMH_EMPTY(bitmask, bucket)     (_bitmask[bucket / MASK_BIT] & (EMH_MASK(bucket))) != 0
+
+#if _WIN32
+    #include <intrin.h>
+#if _WIN64
+    #pragma intrinsic(_umul128)
+#endif
+#endif
+
+namespace emhash7 {
+
+#ifdef EMH_SIZE_TYPE_16BIT
+    typedef uint16_t size_type;
+    static constexpr size_type INACTIVE = 0xFFFF;
+#elif EMH_SIZE_TYPE_64BIT
+    typedef uint64_t size_type;
+    static constexpr size_type INACTIVE = 0 - 0x1ull;
+#else
+    typedef uint32_t size_type;
+    static constexpr size_type INACTIVE = 0 - 0x1u;
+#endif
+
+#ifndef EMH_SIZE_TYPE_16BIT
+static_assert((int)INACTIVE < 0, "INACTIVE must negative (to int)");
+#endif
+
+//count the leading zero bit
+inline static int CTZ(size_t n)
+{
+#if defined(__x86_64__) || defined(_WIN32) || (__BYTE_ORDER__ && __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__)
+
+#elif __BIG_ENDIAN__ || (__BYTE_ORDER__ && __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__)
+    n = __builtin_bswap64(n);
+#else
+    static uint32_t endianness = 0x12345678;
+    const auto is_big = *(const char *)&endianness == 0x12;
+    if (is_big)
+    n = __builtin_bswap64(n);
+#endif
+
+#if _WIN32
+    unsigned long index;
+    #if defined(_WIN64)
+    _BitScanForward64(&index, n);
+    #else
+    _BitScanForward(&index, n);
+    #endif
+#elif defined (__LP64__) || (SIZE_MAX == UINT64_MAX) || defined (__x86_64__)
+    auto index = __builtin_ctzll(n);
+#elif 1
+    auto index = __builtin_ctzl(n);
+#else
+    #if defined (__LP64__) || (SIZE_MAX == UINT64_MAX) || defined (__x86_64__)
+    size_type index;
+    __asm__("bsfq %1, %0\n" : "=r" (index) : "rm" (n) : "cc");
+    #else
+    size_type index;
+    __asm__("bsf %1, %0\n" : "=r" (index) : "rm" (n) : "cc");
+    #endif
+#endif
+
+    return (int)index;
+}
+
+template <typename First, typename Second>
+struct entry {
+    using first_type =  First;
+    using second_type = Second;
+    entry(const First& key, const Second& val, size_type ibucket)
+        :second(val), first(key)
+    {
+        bucket = ibucket;
+    }
+
+    entry(First&& key, Second&& val, size_type ibucket)
+        :second(std::move(val)), first(std::move(key))
+    {
+        bucket = ibucket;
+    }
+
+    template<typename K, typename V>
+    entry(K&& key, V&& val, size_type ibucket)
+        :second(std::forward<V>(val)), first(std::forward<K>(key))
+    {
+        bucket = ibucket;
+    }
+
+    entry(const std::pair<First, Second>& pair)
+        :second(pair.second), first(pair.first)
+    {
+        bucket = INACTIVE;
+    }
+
+    entry(std::pair<First, Second>&& pair)
+        :second(std::move(pair.second)), first(std::move(pair.first))
+    {
+        bucket = INACTIVE;
+    }
+
+    entry(std::tuple<First, Second>&& tup)
+        :second(std::move(std::get<2>(tup))), first(std::move(std::get<1>(tup)))
+    {
+        bucket = INACTIVE;
+    }
+
+    entry(const entry& rhs)
+        :second(rhs.second), first(rhs.first)
+    {
+        bucket = rhs.bucket;
+    }
+
+    entry(entry&& rhs) noexcept
+        :second(std::move(rhs.second)), first(std::move(rhs.first))
+    {
+        bucket = rhs.bucket;
+    }
+
+    entry& operator = (entry&& rhs) noexcept
+    {
+        second = std::move(rhs.second);
+        bucket = rhs.bucket;
+        first  = std::move(rhs.first);
+        return *this;
+    }
+
+    entry& operator = (const entry& rhs)
+    {
+        second = rhs.second;
+        bucket = rhs.bucket;
+        first  = rhs.first;
+        return *this;
+    }
+
+    bool operator == (const entry<First, Second>& p) const
+    {
+        return first == p.first && second == p.second;
+    }
+
+    bool operator == (const std::pair<First, Second>& p) const
+    {
+        return first == p.first && second == p.second;
+    }
+
+    void swap(entry<First, Second>& o)
+    {
+        std::swap(second, o.second);
+        std::swap(first, o.first);
+    }
+
+#if EMH_ORDER_KV || EMH_SIZE_TYPE_64BIT
+    First first;
+    size_type bucket;
+    Second second;
+#else
+    Second second;
+    size_type bucket;
+    First first;
+#endif
+};
+
+/// A cache-friendly hash table with open addressing, linear/qua probing and power-of-two capacity
+template <typename KeyT, typename ValueT, typename HashT = std::hash<KeyT>, typename EqT = std::equal_to<KeyT>>
+class HashMap
+{
+#ifndef EMH_DEFAULT_LOAD_FACTOR
+    constexpr static float EMH_DEFAULT_LOAD_FACTOR = 0.80f;
+    constexpr static float EMH_MIN_LOAD_FACTOR     = 0.25f; //< 0.5
+#endif
+
+public:
+    typedef HashMap<KeyT, ValueT, HashT, EqT> htype;
+    typedef std::pair<KeyT, ValueT>           value_type;
+
+#if EMH_BUCKET_INDEX == 0
+    typedef value_type                        value_pair;
+    typedef std::pair<size_type, value_type>  PairT;
+#elif EMH_BUCKET_INDEX == 2
+    typedef value_type                        value_pair;
+    typedef std::pair<value_type, size_type>  PairT;
+#else
+    typedef entry<KeyT, ValueT>               value_pair;
+    typedef entry<KeyT, ValueT>               PairT;
+#endif
+
+    typedef KeyT   key_type;
+    typedef ValueT val_type;
+    typedef ValueT mapped_type;
+    typedef HashT  hasher;
+    typedef EqT    key_equal;
+    typedef PairT&       reference;
+    typedef const PairT& const_reference;
+
+    class const_iterator;
+    class iterator
+    {
+    public:
+        typedef std::forward_iterator_tag iterator_category;
+        typedef std::ptrdiff_t            difference_type;
+        typedef value_pair                value_type;
+
+        typedef value_pair*               pointer;
+        typedef value_pair&               reference;
+
+        iterator() = default;
+        iterator(const const_iterator& it) : _map(it._map), _bucket(it._bucket), _from(it._from), _bmask(it._bmask) { }
+        iterator(const htype* hash_map, size_type bucket, bool) : _map(hash_map), _bucket(bucket) { init(); }
+#if EMH_ITER_SAFE
+        iterator(const htype* hash_map, size_type bucket) : _map(hash_map), _bucket(bucket) { init(); }
+#else
+        iterator(const htype* hash_map, size_type bucket) : _map(hash_map), _bucket(bucket) { _bmask = _from = 0; }
+#endif
+
+        void init()
+        {
+            _from = (_bucket / SIZE_BIT) * SIZE_BIT;
+            if (_bucket < _map->bucket_count()) {
+                _bmask = *(size_t*)((size_t*)_map->_bitmask + _from / SIZE_BIT);
+                _bmask |= (1ull << _bucket % SIZE_BIT) - 1;
+                _bmask = ~_bmask;
+            } else {
+                _bmask = 0;
+            }
+        }
+
+        size_type bucket() const
+        {
+            return _bucket;
+        }
+
+        void clear(size_type bucket)
+        {
+            if (_bucket / SIZE_BIT == bucket / SIZE_BIT)
+                _bmask &= ~(1ull << (bucket % SIZE_BIT));
+        }
+
+        iterator& next()
+        {
+            goto_next_element();
+            return *this;
+        }
+
+        iterator& operator++()
+        {
+            _bmask &= _bmask - 1;
+            goto_next_element();
+            return *this;
+        }
+
+        iterator operator++(int)
+        {
+            iterator old = *this;
+            _bmask &= _bmask - 1;
+            goto_next_element();
+            return old;
+        }
+
+        reference operator*() const
+        {
+            return _map->EMH_PKV(_pairs, _bucket);
+        }
+
+        pointer operator->() const
+        {
+            return &(_map->EMH_PKV(_pairs, _bucket));
+        }
+
+        bool operator==(const iterator& rhs) const { return _bucket == rhs._bucket; }
+        bool operator!=(const iterator& rhs) const { return _bucket != rhs._bucket; }
+        bool operator==(const const_iterator& rhs) const { return _bucket == rhs._bucket; }
+        bool operator!=(const const_iterator& rhs) const { return _bucket != rhs._bucket; }
+
+    private:
+        void goto_next_element()
+        {
+            if (EMH_LIKELY(_bmask != 0)) {
+                _bucket = _from + CTZ(_bmask);
+                return;
+            }
+
+            do {
+                _bmask = ~*(size_t*)((size_t*)_map->_bitmask + (_from += SIZE_BIT) / SIZE_BIT);
+            } while (_bmask == 0);
+
+            _bucket = _from + CTZ(_bmask);
+        }
+
+    public:
+        const htype* _map;
+        size_type _bucket;
+        size_type _from;
+        size_t    _bmask;
+    };
+
+    class const_iterator
+    {
+    public:
+        typedef std::forward_iterator_tag iterator_category;
+        typedef std::ptrdiff_t            difference_type;
+        typedef value_pair                value_type;
+
+        typedef const value_pair*          pointer;
+        typedef const value_pair&          reference;
+
+        const_iterator(const iterator& it) : _map(it._map), _bucket(it._bucket), _from(it._from), _bmask(it._bmask) { }
+        const_iterator(const htype* hash_map, size_type bucket, bool) : _map(hash_map), _bucket(bucket) { init(); }
+#if EMH_ITER_SAFE
+        const_iterator(const htype* hash_map, size_type bucket) : _map(hash_map), _bucket(bucket) { init(); }
+#else
+        const_iterator(const htype* hash_map, size_type bucket) : _map(hash_map), _bucket(bucket) { _bmask = _from = 0; }
+#endif
+
+        void init()
+        {
+            _from = (_bucket / SIZE_BIT) * SIZE_BIT;
+            if (_bucket < _map->bucket_count()) {
+                _bmask = *(size_t*)((size_t*)_map->_bitmask + _from / SIZE_BIT);
+                _bmask |= (1ull << _bucket % SIZE_BIT) - 1;
+                _bmask = ~_bmask;
+            } else {
+                _bmask = 0;
+            }
+        }
+
+        size_type bucket() const
+        {
+            return _bucket;
+        }
+
+        const_iterator& operator++()
+        {
+            goto_next_element();
+            return *this;
+        }
+
+        const_iterator operator++(int)
+        {
+            const_iterator old(*this);
+            goto_next_element();
+            return old;
+        }
+
+        reference operator*() const
+        {
+            return _map->EMH_PKV(_pairs, _bucket);
+        }
+
+        pointer operator->() const
+        {
+            return &(_map->EMH_PKV(_pairs, _bucket));
+        }
+
+        bool operator==(const const_iterator& rhs) const { return _bucket == rhs._bucket; }
+        bool operator!=(const const_iterator& rhs) const { return _bucket != rhs._bucket; }
+
+    private:
+        void goto_next_element()
+        {
+            _bmask &= _bmask - 1;
+            if (EMH_LIKELY(_bmask != 0)) {
+                _bucket = _from + CTZ(_bmask);
+                return;
+            }
+
+            do {
+                _bmask = ~*(size_t*)((size_t*)_map->_bitmask + (_from += SIZE_BIT) / SIZE_BIT);
+            } while (_bmask == 0);
+
+            _bucket = _from + CTZ(_bmask);
+        }
+
+    public:
+        const htype* _map;
+        size_type _bucket;
+        size_type _from;
+        size_t    _bmask;
+    };
+
+    void init(size_type bucket, float mlf = EMH_DEFAULT_LOAD_FACTOR)
+    {
+        _pairs = nullptr;
+        _bitmask = nullptr;
+        _num_buckets = _num_filled = 0;
+        max_load_factor(mlf);
+        rehash(bucket);
+    }
+
+    HashMap(size_type bucket = 2, float mlf = EMH_DEFAULT_LOAD_FACTOR) noexcept
+    {
+        init(bucket, mlf);
+    }
+
+    size_t AllocSize(uint64_t num_buckets) const
+    {
+        return (num_buckets + EPACK_SIZE) * sizeof(PairT) + (num_buckets + 7) / 8 + BIT_PACK;
+    }
+
+    HashMap(const HashMap& rhs) noexcept
+    {
+        if (rhs.load_factor() > EMH_MIN_LOAD_FACTOR) {
+            _pairs = (PairT*)malloc(AllocSize(rhs._num_buckets));
+            clone(rhs);
+        } else {
+            init(rhs._num_filled + 2, EMH_DEFAULT_LOAD_FACTOR);
+            for (auto it = rhs.begin(); it != rhs.end(); ++it)
+                insert_unique(it->first, it->second);
+        }
+    }
+
+    HashMap(HashMap&& rhs) noexcept
+    {
+#ifndef EMH_ZERO_MOVE
+        init(4);
+#else
+        _num_buckets = _num_filled = _mask = 0;
+        _pairs = nullptr;
+#endif
+        swap(rhs);
+    }
+
+    HashMap(std::initializer_list<value_type> ilist)
+    {
+        init((size_type)ilist.size());
+        for (auto it = ilist.begin(); it != ilist.end(); ++it)
+            do_insert(*it);
+    }
+
+    template<class InputIt>
+    HashMap(InputIt first, InputIt last, size_type bucket_count=4)
+    {
+        init(std::distance(first, last) + bucket_count);
+        for (; first != last; ++first)
+            emplace(*first);
+    }
+
+    HashMap& operator= (const HashMap& rhs) noexcept
+    {
+        if (this == &rhs)
+            return *this;
+
+        if (rhs.load_factor() < EMH_MIN_LOAD_FACTOR) {
+            clear(); free(_pairs); _pairs = nullptr;
+            rehash(rhs._num_filled + 2);
+            for (auto it = rhs.begin(); it != rhs.end(); ++it)
+                insert_unique(it->first, it->second);
+            return *this;
+        }
+
+        if (_num_filled)
+            clearkv();
+
+        if (_num_buckets != rhs._num_buckets) {
+            free(_pairs);
+            _pairs = (PairT*)malloc(AllocSize(rhs._num_buckets));
+        }
+
+        clone(rhs);
+        return *this;
+    }
+
+    HashMap& operator= (HashMap&& rhs) noexcept
+    {
+        if (this != &rhs) {
+            swap(rhs);
+            rhs.clear();
+        }
+        return *this;
+    }
+
+    template<typename Con>
+    bool operator == (const Con& rhs) const
+    {
+        if (size() != rhs.size())
+            return false;
+
+        for (auto it = begin(), last = end(); it != last; ++it) {
+            auto oi = rhs.find(it->first);
+            if (oi == rhs.end() || it->second != oi->second)
+                return false;
+        }
+        return true;
+    }
+
+    template<typename Con>
+    bool operator != (const Con& rhs) const { return !(*this == rhs); }
+
+    ~HashMap() noexcept
+    {
+        if (is_triviall_destructable() && _num_filled) {
+            for (auto it = cbegin(); _num_filled; ++it) {
+                _num_filled --;
+                it->~value_pair();
+            }
+        }
+        free(_pairs);
+    }
+
+    void clone(const HashMap& rhs) noexcept
+    {
+        _hasher      = rhs._hasher;
+        //_eq          = rhs._eq;
+
+        _num_filled  = rhs._num_filled;
+        _mask        = rhs._mask;
+        _mlf         = rhs._mlf;
+        _num_buckets = rhs._num_buckets;
+
+        _bitmask     = decltype(_bitmask)(_pairs + EPACK_SIZE + _num_buckets);
+        auto* opairs = rhs._pairs;
+
+        if (is_copy_trivially())
+            memcpy(_pairs, opairs, AllocSize(_num_buckets));
+        else {
+            memcpy(_pairs + _num_buckets, opairs + _num_buckets, EPACK_SIZE * sizeof(PairT) + (_num_buckets + 7) / 8 + BIT_PACK);
+            for (auto it = rhs.cbegin(); it.bucket() <= _mask; ++it) {
+                const auto bucket = it.bucket();
+                EMH_BUCKET(_pairs, bucket) = EMH_BUCKET(opairs, bucket);
+                new(_pairs + bucket) PairT(opairs[bucket]);
+            }
+        }
+    }
+
+    void swap(HashMap& rhs)
+    {
+        std::swap(_hasher, rhs._hasher);
+        //std::swap(_eq, rhs._eq);
+        std::swap(_pairs, rhs._pairs);
+        std::swap(_num_buckets, rhs._num_buckets);
+        std::swap(_num_filled, rhs._num_filled);
+        std::swap(_mask, rhs._mask);
+        std::swap(_mlf, rhs._mlf);
+        std::swap(_bitmask, rhs._bitmask);
+    }
+
+    // -------------------------------------------------------------
+    iterator begin() noexcept
+    {
+#ifdef EMH_ZERO_MOVE
+        if (0 == _num_filled)
+            return {this, _num_buckets};
+#endif
+
+        const auto bmask = ~(*(size_t*)_bitmask);
+        if (bmask != 0)
+            return {this, (size_type)CTZ(bmask), true};
+
+        iterator it(this, sizeof(bmask) * 8 - 1);
+        return it.next();
+    }
+
+    const_iterator cbegin() const noexcept
+    {
+#ifdef EMH_ZERO_MOVE
+        if (0 == _num_filled)
+            return {this, _num_buckets};
+#endif
+
+        const auto bmask = ~(*(size_t*)_bitmask);
+        if (bmask != 0)
+            return {this, (size_type)CTZ(bmask), true};
+
+        iterator it(this, sizeof(bmask) * 8 - 1);
+        return it.next();
+    }
+
+    iterator last() const
+    {
+        if (_num_filled == 0)
+            return end();
+
+        auto bucket = _mask;
+        while (EMH_EMPTY(_pairs, bucket)) bucket--;
+        return {this, bucket, true};
+    }
+
+    const_iterator begin() const noexcept { return cbegin(); }
+
+    iterator end() noexcept { return {this, _num_buckets}; }
+    const_iterator cend() const { return {this, _num_buckets}; }
+    const_iterator end() const { return cend(); }
+
+    size_type size() const { return _num_filled; }
+    bool empty() const { return _num_filled == 0; }
+
+    size_type bucket_count() const { return _num_buckets; }
+    float load_factor() const { return static_cast<float>(_num_filled) / (_mask + 1); }
+
+    HashT& hash_function() const { return _hasher; }
+    EqT& key_eq() const { return _eq; }
+
+    void max_load_factor(float mlf)
+    {
+        if (mlf < 0.999f && mlf > EMH_MIN_LOAD_FACTOR)
+            _mlf = (uint32_t)((1 << 27) / mlf);
+    }
+
+    constexpr float max_load_factor() const { return (1 << 27) / (float)_mlf; }
+    constexpr size_type max_size() const { return 1ull << (sizeof(size_type) * 8 - 1); }
+    constexpr size_type max_bucket_count() const { return max_size(); }
+
+    size_type bucket_main() const
+    {
+        auto main_size = 0;
+        for (size_type bucket = 0; bucket < _num_buckets; ++bucket) {
+            if (EMH_BUCKET(_pairs, bucket) == bucket)
+                main_size ++;
+        }
+        return main_size;
+    }
+
+#if EMH_STATIS
+    //Returns the bucket number where the element with key k is located.
+    size_type bucket(const KeyT& key) const
+    {
+        const auto bucket = hash_key(key) & _mask;
+        const auto next_bucket = EMH_BUCKET(_pairs, bucket);
+        if (EMH_EMPTY(_pairs, bucket))
+            return 0;
+        else if (bucket == next_bucket)
+            return bucket + 1;
+
+        const auto& bucket_key = EMH_KEY(_pairs, bucket);
+        return (hash_key(bucket_key) & _mask) + 1;
+    }
+
+    //Returns the number of elements in bucket n.
+    size_type bucket_size(const size_type bucket) const
+    {
+        if (EMH_EMPTY(_pairs, bucket))
+            return 0;
+
+        auto next_bucket = EMH_BUCKET(_pairs, bucket);
+        next_bucket = hash_key(EMH_KEY(_pairs, bucket)) & _mask;
+        size_type bucket_size = 1;
+
+        //iterator each item in current main bucket
+        while (true) {
+            const auto nbucket = EMH_BUCKET(_pairs, next_bucket);
+            if (nbucket == next_bucket) {
+                break;
+            }
+            bucket_size++;
+            next_bucket = nbucket;
+        }
+        return bucket_size;
+    }
+
+    size_type get_main_bucket(const size_type bucket) const
+    {
+        if (EMH_EMPTY(_pairs, bucket))
+            return INACTIVE;
+
+        auto next_bucket = EMH_BUCKET(_pairs, bucket);
+        const auto& bucket_key = EMH_KEY(_pairs, bucket);
+        const auto main_bucket = hash_key(bucket_key) & _mask;
+        return main_bucket;
+    }
+
+    size_type get_diss(size_type bucket, size_type next_bucket, const size_type slots) const
+    {
+        const int cahe_line_size = 64;
+        auto pbucket = reinterpret_cast<uint64_t>(&_pairs[bucket]);
+        auto pnext   = reinterpret_cast<uint64_t>(&_pairs[next_bucket]);
+        if (pbucket / cahe_line_size == pnext / cahe_line_size)
+            return 0;
+        size_type diff = pbucket > pnext ? (pbucket - pnext) : (pnext - pbucket);
+        if (diff / cahe_line_size + 1 < slots)
+            return (diff / cahe_line_size + 1);
+        return slots - 1;
+    }
+
+    int get_bucket_info(const size_type bucket, size_type steps[], const size_type slots) const
+    {
+        if (EMH_EMPTY(_pairs, bucket))
+            return -1;
+
+        auto next_bucket = EMH_BUCKET(_pairs, bucket);
+        if ((hash_key(EMH_KEY(_pairs, bucket)) & _mask) != bucket)
+            return 0;
+        else if (next_bucket == bucket)
+            return 1;
+
+        steps[get_diss(bucket, next_bucket, slots)] ++;
+        size_type bucket_size = 2;
+        while (true) {
+            const auto nbucket = EMH_BUCKET(_pairs, next_bucket);
+            if (nbucket == next_bucket)
+                break;
+
+            steps[get_diss(nbucket, next_bucket, slots)] ++;
+            bucket_size ++;
+            next_bucket = nbucket;
+        }
+
+        return bucket_size;
+    }
+
+    void dump_statics(bool show_cache) const
+    {
+        const int slots = 128;
+        size_type buckets[slots + 1] = {0};
+        size_type steps[slots + 1]   = {0};
+        char buff[1024 * 8];
+        for (size_type bucket = 0; bucket < _num_buckets; ++bucket) {
+            auto bsize = get_bucket_info(bucket, steps, slots);
+            if (bsize >= 0)
+                buckets[bsize] ++;
+        }
+
+        size_type sumb = 0, sums = 0, sumn = 0;
+        size_type miss = 0, finds = 0, bucket_coll = 0;
+        double lf = load_factor(), fk = 1.0 / exp(lf), sum_poisson = 0;
+        int bsize = sprintf (buff, "============== buckets size ration ========\n");
+
+        miss += _num_buckets - _num_filled;
+        for (int i = 1, factorial = 1; i < sizeof(buckets) / sizeof(buckets[0]); i++) {
+            double poisson = fk / factorial; factorial *= i; fk *= lf;
+            if (poisson > 1e-13 && i < 20)
+            sum_poisson += poisson * 100.0 * (i - 1) / i;
+
+            const int64_t bucketsi = buckets[i];
+            if (bucketsi == 0)
+                continue;
+
+            sumb += bucketsi;
+            sumn += bucketsi * i;
+            bucket_coll += bucketsi * (i - 1);
+            finds += bucketsi * i * (i + 1) / 2;
+            miss  += bucketsi * i * i;
+            auto errs = (bucketsi * 1.0 * i / _num_filled - poisson) * 100 / poisson;
+            bsize += sprintf(buff + bsize, "  %2d  %8ld  %0.8lf|%0.2lf%%  %2.3lf\n",
+                    i, bucketsi, bucketsi * 1.0 * i / _num_filled, errs, sumn * 100.0 / _num_filled);
+            if (sumn >= _num_filled)
+                break;
+        }
+
+        bsize += sprintf(buff + bsize, "========== collision miss ration ===========\n");
+        for (size_type i = 0; show_cache && i < sizeof(steps) / sizeof(steps[0]); i++) {
+            sums += steps[i];
+            if (steps[i] == 0)
+                continue;
+            if (steps[i] > 10)
+                bsize += sprintf(buff + bsize, "  %2d  %8u  %0.2lf  %.2lf\n", (int)i, steps[i], steps[i] * 100.0 / bucket_coll, sums * 100.0 / bucket_coll);
+        }
+
+        if (sumb == 0)  return;
+
+        bsize += sprintf(buff + bsize, "  _num_filled aver_size k.v size_kv = %u, %.2lf, %s.%s %zd\n",
+                _num_filled, _num_filled * 1.0 / sumb, typeid(KeyT).name(), typeid(ValueT).name(), sizeof(PairT));
+
+        bsize += sprintf(buff + bsize, "  collision, poisson, cache_miss hit_find|hit_miss, load_factor = %.2lf%%,%.2lf%%,%.2lf%% %.2lf|%.2lf, %.2lf\n",
+                (bucket_coll * 100.0 / _num_filled), sum_poisson, (bucket_coll - steps[0]) * 100.0 / _num_filled,
+                finds * 1.0 / _num_filled, miss * 1.0 / _num_buckets, _num_filled * 1.0 / _num_buckets);
+
+        bsize += sprintf(buff + bsize, "============== buckets size end =============\n");
+        buff[bsize + 1] = 0;
+
+#ifdef EMH_LOG
+        EMH_LOG << __FUNCTION__ << "|" << buff << endl;
+#else
+        puts(buff);
+#endif
+        assert(sumn == _num_filled);
+        assert(sums == bucket_coll || !show_cache);
+        assert(bucket_coll == buckets[0]);
+    }
+#endif
+
+    // ------------------------------------------------------------
+    template<typename Key = KeyT>
+    iterator find(const Key& key, size_t key_hash) noexcept
+    {
+        return {this, find_filled_hash(key, key_hash)};
+    }
+
+    template<typename Key = KeyT>
+    const_iterator find(const Key& key, size_t key_hash) const noexcept
+    {
+        return {this, find_filled_hash(key, key_hash)};
+    }
+
+    template<typename Key=KeyT>
+    iterator find(const Key& key) noexcept
+    {
+        return {this, find_filled_bucket(key)};
+    }
+
+    template<typename Key = KeyT>
+    const_iterator find(const Key& key) const noexcept
+    {
+        return {this, find_filled_bucket(key)};
+    }
+
+    template<typename Key = KeyT>
+    ValueT& at(const KeyT& key)
+    {
+        const auto bucket = find_filled_bucket(key);
+        //throw
+        return EMH_VAL(_pairs, bucket);
+    }
+
+    template<typename Key = KeyT>
+    const ValueT& at(const KeyT& key) const
+    {
+        const auto bucket = find_filled_bucket(key);
+        //throw
+        return EMH_VAL(_pairs, bucket);
+    }
+
+    template<typename Key = KeyT>
+    bool contains(const Key& key) const noexcept
+    {
+        return find_filled_bucket(key) != _num_buckets;
+    }
+
+    template<typename Key = KeyT>
+    size_type count(const Key& key) const noexcept
+    {
+        return find_filled_bucket(key) != _num_buckets ? 1 : 0;
+    }
+
+    template<typename Key = KeyT>
+    std::pair<iterator, iterator> equal_range(const Key& key) const noexcept
+    {
+        const auto found = {this, find_filled_bucket(key), true};
+        if (found.bucket() == _num_buckets)
+            return { found, found };
+        else
+            return { found, std::next(found) };
+    }
+
+    template<typename K=KeyT>
+    std::pair<const_iterator, const_iterator> equal_range(const K& key) const
+    {
+        const auto found = {this, find_filled_bucket(key), true};
+        if (found.bucket() == _num_buckets)
+            return { found, found };
+        else
+            return { found, std::next(found) };
+    }
+
+    void merge(HashMap& rhs)
+    {
+        if (empty()) {
+            *this = std::move(rhs);
+            return;
+        }
+
+        for (auto rit = rhs.begin(); rit != rhs.end(); ) {
+            auto fit = find(rit->first);
+            if (fit.bucket() == _num_buckets) {
+                insert_unique(rit->first, std::move(rit->second));
+                rit = rhs.erase(rit);
+            } else {
+                ++rit;
+            }
+        }
+    }
+
+#ifdef EMH_EXT
+    bool try_get(const KeyT& key, ValueT& val) const noexcept
+    {
+        const auto bucket = find_filled_bucket(key);
+        const auto found = bucket != _num_buckets;
+        if (found) {
+            val = EMH_VAL(_pairs, bucket);
+        }
+        return found;
+    }
+
+    /// Returns the matching ValueT or nullptr if k isn't found.
+    ValueT* try_get(const KeyT& key) noexcept
+    {
+        const auto bucket = find_filled_bucket(key);
+        return bucket == _num_buckets ? nullptr : &EMH_VAL(_pairs, bucket);
+    }
+
+    /// Const version of the above
+    ValueT* try_get(const KeyT& key) const noexcept
+    {
+        const auto bucket = find_filled_bucket(key);
+        return bucket == _num_buckets ? nullptr : &EMH_VAL(_pairs, bucket);
+    }
+
+    /// Convenience function.
+    ValueT get_or_return_default(const KeyT& key) const noexcept
+    {
+        const auto bucket = find_filled_bucket(key);
+        return bucket == _num_buckets ? ValueT() : EMH_VAL(_pairs, bucket);
+    }
+#endif
+
+    // -----------------------------------------------------
+    template<typename K = KeyT, typename V = ValueT>
+    std::pair<iterator, bool> do_assign(K&& key, V&& val)
+    {
+        reserve(_num_filled);
+
+        bool isempty;
+        const auto bucket = find_or_allocate(key, isempty);
+        if (isempty) {
+            EMH_NEW(std::forward<K>(key), std::forward<V>(val), bucket);
+        } else {
+            EMH_VAL(_pairs, bucket) = std::move(val);
+        }
+        return { {this, bucket}, isempty };
+    }
+
+    std::pair<iterator, bool> do_insert(const value_type& value)
+    {
+        bool isempty;
+        const auto bucket = find_or_allocate(value.first, isempty);
+        if (isempty) {
+            EMH_NEW(value.first, value.second, bucket);
+        }
+        return { {this, bucket}, isempty };
+    }
+
+    std::pair<iterator, bool> do_insert(value_type&& value)
+    {
+        bool isempty;
+        const auto bucket = find_or_allocate(value.first, isempty);
+        if (isempty) {
+            EMH_NEW(std::move(value.first), std::move(value.second), bucket);
+        }
+        return { {this, bucket}, isempty };
+    }
+
+    template<typename K = KeyT, typename V = ValueT>
+    std::pair<iterator, bool> do_insert(K&& key, V&& val)
+    {
+        bool isempty;
+        const auto bucket = find_or_allocate(key, isempty);
+        if (isempty) {
+            EMH_NEW(std::forward<K>(key), std::forward<V>(val), bucket);
+        }
+        return { {this, bucket}, isempty };
+    }
+
+    std::pair<iterator, bool> insert(const value_type& value)
+    {
+        check_expand_need();
+        return do_insert(value);
+    }
+
+    std::pair<iterator, bool> insert(value_type&& value)
+    {
+        check_expand_need();
+        return do_insert(std::move(value));
+    }
+
+    void insert(std::initializer_list<value_type> ilist)
+    {
+        reserve(ilist.size() + _num_filled);
+        for (auto it = ilist.begin(); it != ilist.end(); ++it)
+            do_insert(*it);
+    }
+
+    template <typename Iter>
+    void insert(Iter first, Iter last)
+    {
+        reserve(std::distance(first, last) + _num_filled);
+        for (auto it = first; it != last; ++it)
+            do_insert(it->first, it->second);
+    }
+
+#if 0
+    template <typename Iter>
+    void insert_unique(Iter begin, Iter end)
+    {
+        reserve(std::distance(begin, end) + _num_filled);
+        for (; begin != end; ++begin)
+            do_insert_unqiue(*begin);
+    }
+#endif
+
+    template<typename K, typename V>
+    size_type insert_unique(K&& key, V&& val)
+    {
+        return do_insert_unqiue(std::forward<K>(key), std::forward<V>(val));
+    }
+
+    size_type insert_unique(value_type&& value)
+    {
+        return do_insert_unqiue(std::move(value.first), std::move(value.second));
+    }
+
+    size_type insert_unique(const value_type& value)
+    {
+        return do_insert_unqiue(value.first, value.second);
+    }
+
+    template<typename K, typename V>
+    inline size_type do_insert_unqiue(K&& key, V&& val)
+    {
+        check_expand_need();
+        auto bucket = find_unique_bucket(key);
+        EMH_NEW(std::forward<K>(key), std::forward<V>(val), bucket);
+        return bucket;
+    }
+
+    std::pair<iterator, bool> insert_or_assign(const KeyT& key, ValueT&& val) { return do_assign(key, std::forward<ValueT>(val)); }
+    std::pair<iterator, bool> insert_or_assign(KeyT&& key, ValueT&& val) { return do_assign(std::move(key), std::forward<ValueT>(val)); }
+
+    template <typename... Args>
+    inline std::pair<iterator, bool> emplace(Args&&... args) noexcept
+    {
+        check_expand_need();
+        return do_insert(std::forward<Args>(args)...);
+    }
+
+    template <class... Args>
+    iterator emplace_hint(const_iterator hint, Args&&... args)
+    {
+        (void)hint;
+        check_expand_need();
+        return do_insert(std::forward<Args>(args)...).first;
+    }
+
+    template<class... Args>
+    std::pair<iterator, bool> try_emplace(const KeyT& key, Args&&... args)
+    {
+        check_expand_need();
+        return do_insert(key, std::forward<Args>(args)...);
+    }
+
+    template<class... Args>
+    std::pair<iterator, bool> try_emplace(KeyT&& key, Args&&... args)
+    {
+        check_expand_need();
+        return do_insert(std::forward<KeyT>(key), std::forward<Args>(args)...);
+    }
+
+    template <class... Args>
+    inline size_type emplace_unique(Args&&... args) noexcept
+    {
+        return insert_unique(std::forward<Args>(args)...);
+    }
+
+    /* Check if inserting a new value rather than overwriting an old entry */
+    ValueT& operator[](const KeyT& key) noexcept
+    {
+        check_expand_need();
+
+        bool isempty;
+        const auto bucket = find_or_allocate(key, isempty);
+        if (isempty) {
+            EMH_NEW(key, std::move(ValueT()), bucket);
+        }
+
+        return EMH_VAL(_pairs, bucket);
+    }
+
+    ValueT& operator[](KeyT&& key) noexcept
+    {
+        check_expand_need();
+
+        bool isempty;
+        const auto bucket = find_or_allocate(key, isempty);
+        if (isempty) {
+            EMH_NEW(std::move(key), std::move(ValueT()), bucket);
+        }
+
+        return EMH_VAL(_pairs, bucket);
+    }
+
+    // -------------------------------------------------------
+    /// Erase an element from the hash table.
+    /// return 0 if element was not found
+    template<typename Key = KeyT>
+    size_type erase(const Key& key)
+    {
+        const auto bucket = erase_key(key);
+        if (bucket == INACTIVE)
+            return 0;
+
+        clear_bucket(bucket);
+        return 1;
+    }
+
+    //iterator erase const_iterator
+    iterator erase(const_iterator cit)
+    {
+        iterator it(cit);
+        return erase(it);
+    }
+
+    /// Erase an element typedef an iterator.
+    /// Returns an iterator to the next element (or end()).
+    iterator erase(iterator it)
+    {
+        const auto bucket = erase_bucket(it._bucket);
+        clear_bucket(bucket);
+        if (bucket == it._bucket) {
+            return ++it;
+        } else {
+            //erase main bucket as next
+            it.clear(bucket);
+            return it;
+        }
+    }
+
+    /// Erase an element typedef an iterator without return next iterator
+    void _erase(const_iterator it)
+    {
+        const auto bucket = erase_bucket(it._bucket);
+        clear_bucket(bucket);
+    }
+
+    template<typename Pred>
+    size_type erase_if(Pred pred)
+    {
+        auto old_size = size();
+        for (auto it = begin(), last = end(); it != last; ) {
+            if (pred(*it))
+                it = erase(it);
+            else
+                ++it;
+        }
+        return old_size - size();
+    }
+
+    static constexpr bool is_triviall_destructable()
+    {
+#if __cplusplus >= 201402L || _MSC_VER > 1600
+        return !(std::is_trivially_destructible<KeyT>::value && std::is_trivially_destructible<ValueT>::value);
+#else
+        return !(std::is_pod<KeyT>::value && std::is_pod<ValueT>::value);
+#endif
+    }
+
+    static constexpr bool is_copy_trivially()
+    {
+#if __cplusplus >= 201402L || _MSC_VER > 1600
+        return (std::is_trivially_copyable<KeyT>::value && std::is_trivially_copyable<ValueT>::value);
+#else
+        return (std::is_pod<KeyT>::value && std::is_pod<ValueT>::value);
+#endif
+    }
+
+    void clearkv()
+    {
+        if (is_triviall_destructable()) {
+            for (auto it = cbegin(); _num_filled; ++it)
+                clear_bucket(it.bucket());
+        }
+    }
+
+    /// Remove all elements, keeping full capacity.
+    void clear()
+    {
+        if (!is_triviall_destructable() && _num_filled) {
+            memset(_bitmask, 0xFFFFFFFF, (_num_buckets + 7) / 8);
+            if (_num_buckets < 8) _bitmask[0] = (1 << _num_buckets) - 1;
+        }
+        else if (_num_filled)
+            clearkv();
+
+        //EMH_BUCKET(_pairs, _num_buckets) = 0; //_last
+        _num_filled = 0;
+    }
+
+    void shrink_to_fit()
+    {
+        rehash(_num_filled + 1);
+    }
+
+    /// Make room for this many elements
+    bool reserve(uint64_t num_elems)
+    {
+        const auto required_buckets = (num_elems * _mlf >> 27);
+        if (EMH_LIKELY(required_buckets < _num_buckets))
+            return false;
+
+#if EMH_HIGH_LOAD
+        if (required_buckets < 64 && _num_filled < _num_buckets)
+            return false;
+#endif
+
+#if EMH_STATIS
+        if (_num_filled > EMH_STATIS) dump_statics(true);
+#endif
+        rehash(required_buckets + 2);
+        return true;
+    }
+
+    void rehash(uint64_t required_buckets)
+    {
+        if (required_buckets < _num_filled)
+            return;
+
+        uint64_t buckets = _num_filled > (1u << 16) ? (1u << 16) : 2u;
+        while (buckets < required_buckets) { buckets *= 2; }
+
+        // no need alloc large bucket for small key sizeof(KeyT) < sizeof(int).
+        // set small a max_load_factor, insert/reserve() will fail and introduce rehash issiue TODO: dothing ?
+        if (sizeof(KeyT) < sizeof(size_type) && buckets >= (1ul << (2 * 8)))
+            buckets = 2ul << (sizeof(KeyT) * 8);
+
+        assert(buckets < max_size() && buckets > _num_filled);
+        //TODO: throwOverflowError
+
+        auto num_buckets = (size_type)buckets;
+        auto old_num_filled = _num_filled;
+        auto old_mask  = _num_buckets - 1;
+        auto old_pairs = _pairs;
+        auto* obmask   = _bitmask;
+
+        _num_filled  = 0;
+        _num_buckets = num_buckets;
+        _mask        = num_buckets - 1;
+
+        _pairs = (PairT*)malloc(AllocSize(_num_buckets));
+        memset((char*)(_pairs + _num_buckets), 0, sizeof(PairT) * EPACK_SIZE);
+
+        _bitmask     = decltype(_bitmask)(_pairs + EPACK_SIZE + num_buckets);
+
+        const auto mask_byte = (num_buckets + 7) / 8;
+        memset(_bitmask, 0xFFFFFFFF, mask_byte);
+        memset(((char*)_bitmask) + mask_byte, 0, BIT_PACK);
+        if (num_buckets < 8)
+            _bitmask[0] = (1 << num_buckets) - 1;
+
+        //for (size_type src_bucket = 0; _num_filled < old_num_filled; src_bucket++) {
+        for (size_type src_bucket = old_mask; _num_filled < old_num_filled; src_bucket --) {
+            if (obmask[src_bucket / MASK_BIT] & (EMH_MASK(src_bucket)))
+                continue;
+
+            auto& key = EMH_KEY(old_pairs, src_bucket);
+            const auto bucket = find_unique_bucket(key);
+            EMH_NEW(std::move(key), std::move(EMH_VAL(old_pairs, src_bucket)), bucket);
+            if (is_triviall_destructable())
+                old_pairs[src_bucket].~PairT();
+        }
+
+#if EMH_REHASH_LOG
+        if (_num_filled > EMH_REHASH_LOG) {
+            auto mbucket = bucket_main();
+            char buff[255] = {0};
+            sprintf(buff, "    _num_filled/collision/main/K.V/pack/ = %u/%.2lf%%(%.2lf%%)/%s.%s/%zd",
+                    _num_filled, 200.0f * (_num_filled - mbucket) / _mask,  100.0f * mbucket / _mask,
+                    typeid(KeyT).name(), typeid(ValueT).name(), sizeof(_pairs[0]));
+#ifdef EMH_LOG
+            static size_t ihashs = 0;
+            EMH_LOG << "rhash_nums = " << ihashs ++ << "|" <<__FUNCTION__ << "|" << buff << endl;
+#else
+            puts(buff);
+#endif
+        }
+#endif
+
+        free(old_pairs);
+        assert(old_num_filled == _num_filled);
+    }
+
+private:
+    // Can we fit another element?
+    inline bool check_expand_need()
+    {
+        return reserve(_num_filled);
+    }
+
+    void clear_bucket(size_type bucket)
+    {
+        EMH_CLS(bucket);
+        _num_filled--;
+        if (is_triviall_destructable())
+            _pairs[bucket].~PairT();
+    }
+
+#if 1
+    //template<typename UType, typename std::enable_if<std::is_integral<UType>::value, size_type>::type = 0>
+    template<typename UType>
+    size_type erase_key(const UType& key)
+    {
+        const auto bucket = hash_key(key) & _mask;
+        if (EMH_EMPTY(_pairs, bucket))
+            return INACTIVE;
+
+        auto next_bucket = EMH_BUCKET(_pairs, bucket);
+        const auto eqkey = _eq(key, EMH_KEY(_pairs, bucket));
+        if (eqkey) {
+            if (next_bucket == bucket)
+                return bucket;
+
+            const auto nbucket = EMH_BUCKET(_pairs, next_bucket);
+            if (is_copy_trivially())
+                EMH_PKV(_pairs, bucket) = EMH_PKV(_pairs, next_bucket);
+            else
+                EMH_PKV(_pairs, bucket).swap(EMH_PKV(_pairs, next_bucket));
+
+            EMH_BUCKET(_pairs, bucket) = (nbucket == next_bucket) ? bucket : nbucket;
+            return next_bucket;
+        } else if (next_bucket == bucket)
+            return INACTIVE;
+        /* else if (EMH_UNLIKELY(bucket != hash_key(EMH_KEY(_pairs, bucket)) & _mask))
+            return INACTIVE;
+        */
+
+        auto prev_bucket = bucket;
+        while (true) {
+            const auto nbucket = EMH_BUCKET(_pairs, next_bucket);
+            if (_eq(key, EMH_KEY(_pairs, next_bucket))) {
+                EMH_BUCKET(_pairs, prev_bucket) = (nbucket == next_bucket) ? prev_bucket : nbucket;
+                return next_bucket;
+            }
+
+            if (nbucket == next_bucket)
+                break;
+            prev_bucket = next_bucket;
+            next_bucket = nbucket;
+        }
+
+        return INACTIVE;
+    }
+#else
+    template<typename UType, typename std::enable_if<!std::is_integral<UType>::value, size_type>::type = 0>
+    size_type erase_key(const UType& key)
+    {
+        const auto bucket = hash_key(key) & _mask;
+        if (EMH_EMPTY(_pairs, bucket))
+            return INACTIVE;
+
+        auto next_bucket = EMH_BUCKET(_pairs, bucket);
+        if (next_bucket == bucket)
+            return _eq(key, EMH_KEY(_pairs, bucket)) ? bucket : INACTIVE;
+//        else if (bucket != hash_key(EMH_KEY(_pairs, bucket)))
+//            return INACTIVE;
+
+        //find erase key and swap to last bucket
+        size_type prev_bucket = bucket, find_bucket = INACTIVE;
+        next_bucket = bucket;
+        while (true) {
+            const auto nbucket = EMH_BUCKET(_pairs, next_bucket);
+            if (_eq(key, EMH_KEY(_pairs, next_bucket))) {
+                find_bucket = next_bucket;
+                if (nbucket == next_bucket) {
+                    EMH_BUCKET(_pairs, prev_bucket) = prev_bucket;
+                    break;
+                }
+            }
+            if (nbucket == next_bucket) {
+                if (find_bucket != INACTIVE) {
+                    EMH_PKV(_pairs, find_bucket).swap(EMH_PKV(_pairs, nbucket));
+//                    EMH_PKV(_pairs, find_bucket) = EMH_PKV(_pairs, nbucket);
+                    EMH_BUCKET(_pairs, prev_bucket) = prev_bucket;
+                    find_bucket = nbucket;
+                }
+                break;
+            }
+            prev_bucket = next_bucket;
+            next_bucket = nbucket;
+        }
+
+        return find_bucket;
+    }
+#endif
+
+    size_type erase_bucket(const size_type bucket)
+    {
+        const auto next_bucket = EMH_BUCKET(_pairs, bucket);
+        const auto main_bucket = hash_key(EMH_KEY(_pairs, bucket)) & _mask;
+        if (bucket == main_bucket) {
+            if (bucket != next_bucket) {
+                const auto nbucket = EMH_BUCKET(_pairs, next_bucket);
+                if (is_copy_trivially())
+                    EMH_PKV(_pairs, bucket) = EMH_PKV(_pairs, next_bucket);
+                else
+                    EMH_PKV(_pairs, bucket).swap(EMH_PKV(_pairs, next_bucket));
+                EMH_BUCKET(_pairs, bucket) = (nbucket == next_bucket) ? bucket : nbucket;
+            }
+            return next_bucket;
+        }
+
+        const auto prev_bucket = find_prev_bucket(main_bucket, bucket);
+        EMH_BUCKET(_pairs, prev_bucket) = (bucket == next_bucket) ? prev_bucket : next_bucket;
+        return bucket;
+    }
+
+    // Find the bucket with this key, or return bucket size
+    template<typename K = KeyT>
+    size_type find_filled_hash(const K& key, const size_t key_hash) const
+    {
+        const auto bucket = key_hash & _mask;
+        if (EMH_EMPTY(_pairs, bucket))
+            return _num_buckets;
+
+        auto next_bucket = bucket;
+        while (true) {
+            if (_eq(key, EMH_KEY(_pairs, next_bucket)))
+                return next_bucket;
+
+            const auto nbucket = EMH_BUCKET(_pairs, next_bucket);
+            if (nbucket == next_bucket)
+                break;
+            next_bucket = nbucket;
+        }
+
+        return _num_buckets;
+    }
+
+    // Find the bucket with this key, or return bucket size
+    template<typename K = KeyT>
+    size_type find_filled_bucket(const K& key) const
+    {
+        const auto bucket = hash_key(key) & _mask;
+        if (EMH_EMPTY(_pairs, bucket))
+            return _num_buckets;
+
+        auto next_bucket = bucket;
+//        else if (bucket != (hash_key(bucket_key) & _mask))
+//            return _num_buckets;
+
+        while (true) {
+            if (_eq(key, EMH_KEY(_pairs, next_bucket)))
+                return next_bucket;
+
+            const auto nbucket = EMH_BUCKET(_pairs, next_bucket);
+            if (nbucket == next_bucket)
+                return _num_buckets;
+            next_bucket = nbucket;
+        }
+
+        return 0;
+    }
+
+    //kick out bucket and find empty to occpuy
+    //it will break the orgin link and relnik again.
+    //before: main_bucket-->prev_bucket --> bucket   --> next_bucket
+    //atfer : main_bucket-->prev_bucket --> (removed)--> new_bucket--> next_bucket
+    size_type kickout_bucket(const size_type kmain, const size_type kbucket)
+    {
+        const auto next_bucket = EMH_BUCKET(_pairs, kbucket);
+        const auto new_bucket  = find_empty_bucket(next_bucket, kbucket);
+        const auto prev_bucket = find_prev_bucket(kmain, kbucket);
+        new(_pairs + new_bucket) PairT(std::move(_pairs[kbucket]));
+        if (is_triviall_destructable())
+            _pairs[kbucket].~PairT();
+
+        if (next_bucket == kbucket)
+            EMH_BUCKET(_pairs, new_bucket) = new_bucket;
+        EMH_BUCKET(_pairs, prev_bucket) = new_bucket;
+
+        EMH_SET(new_bucket);
+        return kbucket;
+    }
+
+/*
+** inserts a new key into a hash table; first check whether key's main
+** bucket/position is free. If not, check whether colliding node/bucket is in its main
+** position or not: if it is not, move colliding bucket to an empty place and
+** put new key in its main position; otherwise (colliding bucket is in its main
+** position), new key goes to an empty position. ***/
+
+    template<typename K=KeyT>
+    size_type find_or_allocate(const K& key, bool& isempty)
+    {
+        const auto bucket = hash_key(key) & _mask;
+        const auto& bucket_key = EMH_KEY(_pairs, bucket);
+        if (EMH_EMPTY(_pairs, bucket)) {
+            isempty = true;
+            return bucket;
+        }
+        else if (_eq(key, bucket_key)) {
+            isempty = false;
+            return bucket;
+        }
+
+        isempty = true;
+        auto next_bucket = EMH_BUCKET(_pairs, bucket);
+        //check current bucket_key is in main bucket or not
+        const auto kmain_bucket = hash_key(bucket_key) & _mask;
+        if (kmain_bucket != bucket)
+            return kickout_bucket(kmain_bucket, bucket);
+        else if (next_bucket == bucket)
+            return EMH_BUCKET(_pairs, next_bucket) = find_empty_bucket(next_bucket, bucket);
+
+#if EMH_LRU_SET
+        auto prev_bucket = bucket;
+#endif
+        //find next linked bucket and check key, if lru is set then swap current key with prev_bucket
+        while (true) {
+            if (EMH_UNLIKELY(_eq(key, EMH_KEY(_pairs, next_bucket)))) {
+                isempty = false;
+#if EMH_LRU_SET
+                EMH_PKV(_pairs, next_bucket).swap(EMH_PKV(_pairs, prev_bucket));
+                return prev_bucket;
+#else
+                return next_bucket;
+#endif
+            }
+
+#if EMH_LRU_SET
+            prev_bucket = next_bucket;
+#endif
+
+            const auto nbucket = EMH_BUCKET(_pairs, next_bucket);
+            if (nbucket == next_bucket)
+                break;
+            next_bucket = nbucket;
+        }
+
+        //find a new empty and link it to tail, TODO link after main bucket?
+        const auto new_bucket = find_empty_bucket(next_bucket, bucket);// : find_empty_bucket(next_bucket);
+        return EMH_BUCKET(_pairs, next_bucket) = new_bucket;
+    }
+
+    // key is not in this map. Find a place to put it.
+    size_type find_empty_bucket(const size_type bucket_from, const size_type main_bucket)
+    {
+#ifdef EMH_ALIGN64 // only works 64bit
+        const auto boset  = bucket_from % MASK_BIT;
+        auto* const align = _bitmask + bucket_from / MASK_BIT;
+        const auto bmask  = ((size_t)align[1] << (MASK_BIT - boset)) | (align[0] >> boset);
+        if (EMH_LIKELY(bmask != 0))
+            return bucket_from + CTZ(bmask);
+#elif EMH_ITER_SAFE
+        const auto boset = bucket_from % 8;
+        auto* const start = (uint8_t*)_bitmask + bucket_from / 8;
+        size_t bmask; memcpy(&bmask, start + 0, sizeof(bmask)); bmask >>= boset;// bmask |= ((size_t)start[8] << (SIZE_BIT - boset));
+        if (EMH_LIKELY(bmask != 0))
+            return bucket_from + CTZ(bmask);
+#else
+        const auto boset  = main_bucket % 8;
+        auto* const align = (uint8_t*)_bitmask + main_bucket / 8; (void)bucket_from;
+        const size_t bmask  = (*(size_t*)(align) >> boset);// & 0xF0F0F0F0FF0FF0FFull;//
+        if (EMH_LIKELY(bmask != 0))
+            return main_bucket + CTZ(bmask);
+#endif
+
+        const auto qmask = _mask / SIZE_BIT;
+        if (1) {
+            const size_type step = (main_bucket - SIZE_BIT / 4) & qmask;
+            const auto bmask3 = *((size_t*)_bitmask + step);
+            if (bmask3 != 0)
+                return step * SIZE_BIT + CTZ(bmask3);
+        }
+
+        for (; ;) {
+           auto& _last = EMH_BUCKET(_pairs, _num_buckets);
+            const auto bmask2 = *((size_t*)_bitmask + _last);
+            if (bmask2 != 0)
+                return _last * SIZE_BIT + CTZ(bmask2);
+
+            const auto next1 = (qmask / 2 + _last) & qmask;
+            const auto bmask1 = *((size_t*)_bitmask + next1);
+            if (bmask1 != 0) {
+                //_last = next1;
+                return next1 * SIZE_BIT + CTZ(bmask1);
+            }
+            _last = (_last + 1) & qmask;
+        }
+
+        return 0;
+    }
+
+    // key is not in this map. Find a place to put it.
+    size_type find_unique_empty(const size_type bucket_from, const size_t main_bucket)
+    {
+#ifdef EMH_ALIGN64
+        const auto boset  = bucket_from % MASK_BIT;
+        auto* const align = _bitmask + bucket_from / MASK_BIT;
+        const auto bmask  = ((size_t)align[1] << (MASK_BIT - boset)) | (align[0] >> boset);
+        static_assert(sizeof(size_t) > 4);
+#elif EMH_ITER_SAFE
+        const auto boset = bucket_from % 8;
+        auto* const start = (uint8_t*)_bitmask + bucket_from / 8;
+        size_t bmask; memcpy(&bmask, start + 0, sizeof(bmask)); bmask >>= boset;
+#else
+        const auto boset  = bucket_from % 8; (void)main_bucket;
+        auto* const align = (uint8_t*)_bitmask + bucket_from / 8;
+        const auto bmask  = (*(size_t*)(align) >> boset); //maybe not aligned and warning
+#endif
+        if (EMH_LIKELY(bmask != 0))
+            return bucket_from + CTZ(bmask);
+
+        const auto qmask = _mask / SIZE_BIT;
+        for (auto last = (bucket_from + _mask) & qmask; ;) {
+            const auto bmask2 = *((size_t*)_bitmask + last);// & 0xF0F0F0F0FF0FF0FFull;
+            if (EMH_LIKELY(bmask2 != 0))
+                return last * SIZE_BIT + CTZ(bmask2);
+            last = (last + 1) & qmask;
+        }
+
+        return 0;
+    }
+
+    size_type find_last_bucket(size_type main_bucket) const
+    {
+        auto next_bucket = EMH_BUCKET(_pairs, main_bucket);
+        if (next_bucket == main_bucket)
+            return main_bucket;
+
+        while (true) {
+            const auto nbucket = EMH_BUCKET(_pairs, next_bucket);
+            if (nbucket == next_bucket)
+                return next_bucket;
+            next_bucket = nbucket;
+        }
+    }
+
+    size_type find_prev_bucket(size_type main_bucket, const size_type bucket) const
+    {
+        auto next_bucket = EMH_BUCKET(_pairs, main_bucket);
+        if (next_bucket == bucket)
+            return main_bucket;
+
+        while (true) {
+            const auto nbucket = EMH_BUCKET(_pairs, next_bucket);
+            if (nbucket == bucket)
+                return next_bucket;
+            next_bucket = nbucket;
+        }
+    }
+
+    size_type find_unique_bucket(const KeyT& key)
+    {
+        const size_type bucket = hash_key(key) & _mask;
+        if (EMH_EMPTY(_pairs, bucket))
+            return bucket;
+
+        //check current bucket_key is in main bucket or not
+        const auto kmain_bucket = hash_key(EMH_KEY(_pairs, bucket)) & _mask;
+        if (EMH_UNLIKELY(kmain_bucket != bucket))
+            return kickout_bucket(kmain_bucket, bucket);
+
+        auto next_bucket = EMH_BUCKET(_pairs, bucket);
+        if (next_bucket != bucket)
+            next_bucket = find_last_bucket(next_bucket);
+
+        //find a new empty and link it to tail
+        return EMH_BUCKET(_pairs, next_bucket) = find_unique_empty(next_bucket, bucket);
+    }
+
+#if EMH_INT_HASH
+    static constexpr uint64_t KC = UINT64_C(11400714819323198485);
+    static inline uint64_t hash64(uint64_t key)
+    {
+#if __SIZEOF_INT128__ && EMH_INT_HASH == 1
+        __uint128_t r = key; r *= KC;
+        return (uint64_t)(r >> 64) + (uint64_t)r;
+#elif EMH_INT_HASH == 2
+        //MurmurHash3Mixer
+        uint64_t h = key;
+        h ^= h >> 33;
+        h *= 0xff51afd7ed558ccd;
+        h ^= h >> 33;
+        h *= 0xc4ceb9fe1a85ec53;
+        h ^= h >> 33;
+        return h;
+#elif _WIN64 && EMH_INT_HASH == 1
+        uint64_t high;
+        return _umul128(key, KC, &high) + high;
+#elif EMH_INT_HASH == 3
+        auto ror  = (key >> 32) | (key << 32);
+        auto low  = key * 0xA24BAED4963EE407ull;
+        auto high = ror * 0x9FB21C651E98DF25ull;
+        auto mix  = low + high;
+        return mix;
+#elif EMH_INT_HASH == 1
+        uint64_t r = key * UINT64_C(0xca4bcaa75ec3f625);
+        return (r >> 32) + r;
+#elif EMH_WYHASH64
+        return wyhash64(key, KC);
+#else
+        uint64_t x = key;
+        x = (x ^ (x >> 30)) * UINT64_C(0xbf58476d1ce4e5b9);
+        x = (x ^ (x >> 27)) * UINT64_C(0x94d049bb133111eb);
+        x = x ^ (x >> 31);
+        return x;
+#endif
+    }
+#endif
+
+    template<typename UType, typename std::enable_if<std::is_integral<UType>::value, size_type>::type = 0>
+    inline size_type hash_key(const UType key) const
+    {
+#if EMH_INT_HASH
+        return hash64(key);
+#elif EMH_IDENTITY_HASH
+        return key + (key >> 24);
+#else
+        return (size_type)_hasher(key);
+#endif
+    }
+
+    template<typename UType, typename std::enable_if<std::is_same<UType, std::string>::value, size_type>::type = 0>
+    inline size_type hash_key(const UType& key) const
+    {
+#if EMH_WY_HASH
+        return wyhash(key.data(), key.size(), 0);
+#else
+        return (size_type)_hasher(key);
+#endif
+    }
+
+    template<typename UType, typename std::enable_if<!std::is_integral<UType>::value && !std::is_same<UType, std::string>::value, size_type>::type = 0>
+    inline size_type hash_key(const UType& key) const
+    {
+        return (size_type)_hasher(key);
+    }
+
+private:
+    uint32_t* _bitmask;
+    PairT*    _pairs;
+    HashT     _hasher;
+    EqT       _eq;
+    size_type _mask;
+    size_type _num_buckets;
+
+    size_type _num_filled;
+    uint32_t  _mlf;
+
+private:
+    static constexpr uint32_t BIT_PACK = sizeof(_bitmask[0]) * 2;
+    static constexpr uint32_t MASK_BIT = sizeof(_bitmask[0]) * 8;
+    static constexpr uint32_t SIZE_BIT = sizeof(size_t) * 8;
+    static constexpr uint32_t EPACK_SIZE = sizeof(PairT) >= sizeof(size_t) == 0 ? 1 : 2; // > 1
+};
+}
+// namespace emhash7
+#if __cplusplus >= 201103L
+//template <class Key, class Val> using ehmap7 = emhash7::HashMap<Key, Val, std::hash<Key>, std::equal_to<Key>>;
+#endif
+
+//TODO
+//2. improve rehash and find miss performance(reduce peak memory)
+//3. dump or Serialization interface
+//4. node hash map support
+//5. load_factor > 1.0 && add grow ration
+//... https://godbolt.org/