hash_map.h

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// -*- mode: c++; tab-width: 4; indent-tabs-mode: t; eval: (progn (c-set-style "stroustrup") (c-set-offset 'innamespace 0)); -*-
// vi:set ts=4 sts=4 sw=4 noet :
// Copyright 2010, 2011, 2012 The TPIE development team
// 
// This file is part of TPIE.
// 
// TPIE is free software: you can redistribute it and/or modify it under
// the terms of the GNU Lesser General Public License as published by the
// Free Software Foundation, either version 3 of the License, or (at your
// option) any later version.
// 
// TPIE 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 Lesser General Public
// License for more details.
// 
// You should have received a copy of the GNU Lesser General Public License
// along with TPIE.  If not, see <http://www.gnu.org/licenses/>
#ifndef __TPIE_HASHMAP_H__
#define __TPIE_HASHMAP_H__


#include <tpie/array.h>
#include <tpie/unused.h>
#include <cmath>
#include <algorithm>
#include <iostream>
#include <tpie/prime.h>
#include <tpie/hash.h>

namespace tpie {

template <typename value_t, typename hash_t, typename equal_t, typename index_t>
class chaining_hash_table {
private:
    static const float sc;
    
#pragma pack(push, 1)
    struct bucket_t {
        value_t value;
        index_t next;
    };
#pragma pack(pop)
    
    size_t first_free;
    array<index_t> list;
    array<bucket_t> buckets;

    hash_t h;
    equal_t e;
public:
    size_t size;

    value_t unused;

    static double memory_coefficient() {
        return array<index_t>::memory_coefficient() *sc + array<bucket_t>::memory_coefficient();
    }

    static double memory_overhead() {
        return array<index_t>::memory_coefficient() * 100.0 
            + array<index_t>::memory_overhead() + sizeof(chaining_hash_table) 
            + array<bucket_t>::memory_overhead()
            - sizeof(array<index_t>)
            - sizeof(array<bucket_t>);
    }

    inline value_t & get(size_t idx) {return buckets[idx].value;}

    inline const value_t & get(size_t idx) const {return buckets[idx].value;}

    void clear() {
        first_free = 0;
        for (size_t i=0; i < buckets.size(); ++i) {
            buckets[i].value = unused;
            buckets[i].next = static_cast<index_t>(i+1);
        }
        for (typename array<index_t>::iterator i=list.begin(); i != list.end(); ++i)
            *i = std::numeric_limits<index_t>::max();
    }

    void resize(size_t z) {
        buckets.resize(z);
        size_t x=static_cast<size_t>(99+static_cast<double>(z)*sc)|1;
        while (!is_prime(x)) x -= 2;
        list.resize(x);
        clear();
    }

    chaining_hash_table(size_t ee,
                        value_t u,
                        const hash_t & hash,
                        const equal_t & equal):  h(hash), e(equal), size(0), unused(u) {resize(ee);};

    inline size_t begin() {
        if (size == 0) return buckets.size();
        for(size_t i=0; true; ++i)
            if (buckets[i].value != unused) return i;
    }

    inline size_t end() const {return buckets.size();}  

    inline size_t find(const value_t & value) const {
        size_t v = list[h(value) % list.size()];
        while (v != std::numeric_limits<index_t>::max()) {
            if (e(buckets[v].value, value)) return v;
            v = buckets[v].next;
        }
        return buckets.size();
    }

    inline std::pair<size_t, bool> insert(const value_t & val) {
        // First, look for the value in table.
        size_t hv = h(val) % list.size();
        size_t v = list[hv];
        while (v != std::numeric_limits<index_t>::max()) {
            if (e(buckets[v].value, val)) return std::make_pair(v, false);
            v = buckets[v].next;
        }
        // It wasn't found. Insert into free bucket.
        v = first_free;
        first_free = buckets[v].next;
        buckets[v].value = val;
        buckets[v].next = list[hv];
        list[hv] = v;
        ++size;
        return std::make_pair(v, true);
    }

    inline void erase(const value_t & val) {
        size_t hv = h(val) % list.size();
        size_t cur = list[hv];
        size_t prev = std::numeric_limits<size_t>::max();

        while (!e(buckets[cur].value, val)) {
            prev = cur;
            cur = buckets[cur].next;
        }
        
        if (prev == std::numeric_limits<size_t>::max())
            list[hv] = buckets[cur].next;
        else
            buckets[prev].next = buckets[cur].next;

        buckets[cur].next = first_free;
        buckets[cur].value = unused;
        first_free = cur;
        --size;
    }
};

template <typename value_t, typename hash_t, typename equal_t, typename index_t>
class linear_probing_hash_table {
private:
    static const float sc;
    array<value_t> elements;
    hash_t h;
    equal_t e;
public:
    size_t size;

    value_t unused;

    static double memory_coefficient() {
        return array<value_t>::memory_coefficient() *sc;
    }

    static double memory_overhead() {
        return array<value_t>::memory_coefficient() * 100.0 
            + array<value_t>::memory_overhead() + sizeof(linear_probing_hash_table) - sizeof(array<value_t>);
    }

    void clear() {
        for (typename array<value_t>::iterator i=elements.begin(); i != elements.end(); ++i)
            *i = unused;
    }

    void resize(size_t element_count) {
        size_t x=(99+static_cast<size_t>(static_cast<float>(element_count)*sc))|1;
        while (!is_prime(x)) x -= 2;
        elements.resize(x, unused);
    }

    linear_probing_hash_table(size_t ee, value_t u,
                              const hash_t & hash, const equal_t & equal):
        h(hash), e(equal), size(0), unused(u) {resize(ee);}
    
    inline size_t find(const value_t & value) const {
        size_t v = h(value) % elements.size();
        while (elements[v] != unused) {
            if (e(elements[v], value)) return v;
            v = (v + 1) % elements.size();
        }
        return elements.size();
    }


    inline size_t end() const {return elements.size();}

    inline size_t begin() const {
        if (size == 0) return elements.size();
        for(size_t i=0; true; ++i)
            if (elements[i] != unused) return i;
    }

    value_t & get(size_t idx) {return elements[idx];}

    const value_t & get(size_t idx) const {return elements[idx];}

    inline std::pair<size_t, bool> insert(const value_t & val) {
        size_t v = h(val) % elements.size();
        while (elements[v] != unused) {
            if (e(elements[v],val)) {return std::make_pair(v, false);}
            v = (v + 1) % elements.size();
        }
        ++size;
        elements[v] = val;
        return std::make_pair(v, true);
    }

    inline void erase(const value_t & val) {
        size_t slot = find(val);
        size_t cur = (slot+1) % elements.size();
        assert(size < elements.size());
        while (elements[cur] != unused) {      
            size_t x = h(elements[cur]) % elements.size();
            if (x <= slot && (cur > slot || x > cur)) {
                elements[slot] = elements[cur];
                slot = cur;
            }
            cur = (cur+1) % elements.size();
        }
        elements[slot] = unused;
        --size;
    }
};

template <typename key_t, 
          typename data_t, 
          typename hash_t=hash<key_t>,
          typename equal_t=std::equal_to<key_t>, 
          typename index_t=size_t,
          template <typename, typename, typename, typename> class table_t = chaining_hash_table
          >
class hash_map: public linear_memory_base< hash_map<key_t, data_t, hash_t, equal_t, index_t, table_t> > {
public:
    typedef std::pair<key_t, data_t> value_t;
private:
    struct key_equal_t {
        equal_t e;
        key_equal_t(const equal_t & equal): e(equal) {}
        inline bool operator()(const value_t & a, const value_t & b) const {
            return e(a.first, b.first);
        }
    };

    struct key_hash_t {
        hash_t h;
        key_hash_t(const hash_t & hash): h(hash) {}
        inline size_t operator()(const value_t & a) const {
            return h(a.first);
        }
    };

    typedef table_t<value_t, key_hash_t, key_equal_t, index_t> tbl_t;

    tbl_t tbl;

    template <typename IT>
    class iter_base {
    protected:
        IT & tbl;
        size_t cur;
        iter_base(IT & t, size_t c): tbl(t), cur(c) {};
        friend class hash_map::iterator;
        friend class hash_map;
    public:
        inline const key_t & key() const {return tbl.get(cur).first;}
        inline const data_t & value() const {return tbl.get(cur).second;}
        inline const value_t & operator*() const {return tbl.get(cur);}
        inline const value_t * operator->() const {return &tbl.get(cur);}

        template <typename IIT>
        inline bool operator==(const iter_base<IIT> & o) const {return o.cur == cur;}
        template <typename IIT>
        inline bool operator!=(const iter_base<IIT> & o) const {return o.cur != cur;}
        inline void operator++() {
            ++cur;
            while (cur != tbl.end()) {
                if (tbl.get(cur) != tbl.unused) break;
                ++cur;
            }
        }
    };
public:
    typedef iter_base<const tbl_t> const_iterator;
    
    class iterator: public iter_base<tbl_t> {
    private:
        typedef iter_base<tbl_t> p_t;
        friend class hash_map;
        inline iterator(tbl_t & tbl, size_t cur): p_t(tbl, cur) {}
        using p_t::tbl;
        using p_t::cur;
    public:
        inline key_t & key() {return tbl.get(cur)->first;}
        inline data_t & value() {return tbl.get(cur)->second;}
        inline value_t & operator*() {return tbl.get(cur);}
        inline value_t * operator->() {return &tbl.get(cur);}
        inline operator const_iterator() const {return const_iterator(tbl, cur);}
        inline bool operator==(const const_iterator & o) const {return o.cur == cur;}
        inline bool operator!=(const const_iterator & o) const {return o.cur != cur;}
    };


    static double memory_coefficient() {
        return tbl_t::memory_coefficient();
    }

    static double memory_overhead() {
        return tbl_t::memory_overhead() - sizeof(tbl_t) + sizeof(hash_map);
    }

    inline hash_map(size_t size=0, const hash_t & hash=hash_t(),
                    const equal_t & equal=equal_t(),
                    value_t u=default_unused<value_t>::v() ):
        tbl(size, u, key_hash_t(hash), key_equal_t(equal)) {}
    
    inline void resize(size_t size) {tbl.resize(size);}

    inline void erase(const key_t & key) {
        tbl.erase(value_t(key, tbl.unused.second));
    }
    
    inline void erase(const iterator & iter) {erase(iter.key());}

    inline bool insert(const key_t & key, const data_t & data) {
        return tbl.insert(value_t(key, data)).second;
    }

    inline data_t & operator[](const key_t & key) {
        return tbl.get(tbl.insert(value_t(key, tbl.unused.second)).first).second;
    }
    
    inline const data_t & operator[](const key_t & key) const {
        return tbl.get(tbl.find(key))->second;
    }
    
    inline iterator find(const key_t & key) {
        return iterator(tbl, tbl.find(value_t(key, tbl.unused.second)));
    }

    inline const_iterator find(const key_t & key) const {
        return const_iterator(tbl, tbl.find(value_t(key, tbl.unused.second)));
    }

    inline bool contains(const key_t & key) const {
        return tbl.find(value_t(key, tbl.unused.second)) != tbl.end();
    }

    inline iterator begin() {return iterator(tbl, tbl.begin());}

    inline const_iterator begin() const {return const_iterator(tbl, tbl.begin());}

    inline const_iterator cbegin() const {return const_iterator(tbl, tbl.begin());}

    inline iterator end() {return iterator(tbl, tbl.end());}

    inline const_iterator end() const {return const_iterator(tbl, tbl.end());}

    inline const_iterator cend() const {return const_iterator(tbl, tbl.end());}

    inline size_t size() const {return tbl.size;}

    inline void clear() {tbl.clear();}
};

template <typename key_t,
          typename hash_t=hash<key_t>,
          typename equal_t=std::equal_to<key_t>,
          typename index_t=size_t,
          template <typename, typename, typename, typename> class table_t=linear_probing_hash_table>
class hash_set : public linear_memory_base< hash_set<key_t, hash_t, equal_t, index_t, table_t> > {
private:
    typedef table_t<key_t, hash_t, equal_t, index_t> tbl_t;
    tbl_t tbl;
    typedef key_t value_t;

    template <typename IT>
    class iter_base {
    protected:
        IT & tbl;
        size_t cur;
        iter_base(IT & t, size_t c): tbl(t), cur(c) {};
        //friend class hash_set::iterator;
        friend class hash_set;
    public:
        inline const value_t & operator*() const {return tbl.get(cur);}
        inline const value_t * operator->() const {return &tbl.get(cur);}
        inline bool operator==(iter_base & o) const {return o.cur == cur;}
        inline bool operator!=(iter_base & o) const {return o.cur != cur;}
        inline void operator++() {
            while (cur != tbl.end()) {
                ++cur;
                if (tbl.get(cur) != tbl.unused) break;
            }
        }
    };
public:
    typedef iter_base<const tbl_t> const_iterator;
    
    class iterator: public iter_base<tbl_t> {
    private:
        typedef iter_base<tbl_t> p_t;
        friend class hash_set;
        inline iterator(tbl_t & tbl, size_t cur): p_t(tbl, cur) {}
        using p_t::tbl;
        using p_t::cur;
    public:
        inline value_t & operator*() {return tbl.get(cur);}
        inline value_t * operator->() {return &tbl.get(cur);}
        inline operator const_iterator() const {return const_iterator(tbl, cur);}
        inline bool operator==(const const_iterator & o) const {return o.cur == cur;}
        inline bool operator!=(const const_iterator & o) const {return o.cur != cur;}
    };


    static double memory_coefficient() {
        return tbl_t::memory_coefficient();
    }

    static double memory_overhead() {
        return tbl_t::memory_overhead() - sizeof(tbl_t) + sizeof(hash_set);
    }

    inline hash_set(size_t size=0, 
                    const hash_t & hash=hash_t(), const equal_t & equal=equal_t(),
                    value_t u=default_unused<value_t>::v()):
        tbl(size, u, hash, equal) {}

    inline void resize(size_t size) {tbl.resize(size);}

    inline void erase(const key_t & key) {tbl.erase(key);}

    inline void erase(const iterator & iter) {erase(iter.key());}

    inline bool insert(const key_t & key) {
        return tbl.insert(key).second;
    }

    inline iterator find(const key_t & key) {
        return iterator(tbl, tbl.find(key));
    }

    inline const_iterator find(const key_t & key) const {
        return const_iterator(tbl, tbl.find(key));
    }

    inline bool contains(const key_t & key) const {return tbl.find(key) != tbl.end();}

    inline iterator begin() {return iterator(tbl, tbl.begin());}

    inline const_iterator begin() const {return const_iterator(tbl, tbl.begin());}

    inline const_iterator cbegin() const {return const_iterator(tbl, tbl.begin());}

    inline iterator end() {return iterator(tbl, tbl.end());}

    inline const_iterator end() const {return const_iterator(tbl, tbl.end());}

    inline const_iterator cend() const {return const_iterator(tbl, tbl.end());}

    inline size_t size() const {return tbl.size;}

    inline void clear() const {tbl.clear();}
};


template <typename value_t, typename hash_t, typename equal_t, typename index_t>
const float linear_probing_hash_table<value_t, hash_t, equal_t, index_t>::sc = 2.0f;

template <typename value_t, typename hash_t, typename equal_t, typename index_t>
const float chaining_hash_table<value_t, hash_t, equal_t, index_t>::sc = 2.f;

}
#endif //__TPIE_HASHMAP_H__