sat-solver/Map.h

/*******************************************************************************************[Map.h]
MiniSat -- Copyright (c) 2003-2006, Niklas Een, Niklas Sorensson

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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
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**************************************************************************************************/

#ifndef Map_h
#define Map_h

#include <stdint.h>

#include "Vec.h"

//=================================================================================================
// Default hash/equals functions
//

template<class K> struct Hash  { uint32_t operator()(const K& k)               const { return hash(k);  } };
template<class K> struct Equal { bool     operator()(const K& k1, const K& k2) const { return k1 == k2; } };

template<class K> struct DeepHash  { uint32_t operator()(const K* k)               const { return hash(*k);  } };
template<class K> struct DeepEqual { bool     operator()(const K* k1, const K* k2) const { return *k1 == *k2; } };

//=================================================================================================
// Some primes
//

static const int nprimes          = 25;
static const int primes [nprimes] = { 31, 73, 151, 313, 643, 1291, 2593, 5233, 10501, 21013, 42073, 84181, 168451, 337219, 674701, 1349473, 2699299, 5398891, 10798093, 21596719, 43193641, 86387383, 172775299, 345550609, 691101253 };

//=================================================================================================
// Hash table implementation of Maps
//

template<class K, class D, class H = Hash<K>, class E = Equal<K> >
class Map {
    struct Pair { K key; D data; };

    H          hash;
    E          equals;

    vec<Pair>* table;
    int        cap;
    int        size;

    // Don't allow copying (error prone):
    Map<K,D,H,E>&  operator = (Map<K,D,H,E>& other) { assert(0); }
                   Map        (Map<K,D,H,E>& other) { assert(0); }

    int32_t index  (const K& k) const { return hash(k) % cap; }
    void   _insert (const K& k, const D& d) { table[index(k)].push(); table[index(k)].last().key = k; table[index(k)].last().data = d; }
    void    rehash () {
        const vec<Pair>* old = table;

        int newsize = primes[0];
        for (int i = 1; newsize <= cap && i < nprimes; i++)
           newsize = primes[i];

        table = new vec<Pair>[newsize];

        for (int i = 0; i < cap; i++){
            for (int j = 0; j < old[i].size(); j++){
                _insert(old[i][j].key, old[i][j].data); }}

        delete [] old;

        cap = newsize;
    }

    
    public:

     Map () : table(NULL), cap(0), size(0) {}
     Map (const H& h, const E& e) : Map(), hash(h), equals(e) {}
    ~Map () { delete [] table; }

    void insert (const K& k, const D& d) { if (size+1 > cap / 2) rehash(); _insert(k, d); size++; }
    bool peek   (const K& k, D& d) {
        if (size == 0) return false;
        const vec<Pair>& ps = table[index(k)];
        for (int i = 0; i < ps.size(); i++)
            if (equals(ps[i].key, k)){
                d = ps[i].data;
                return true; } 
        return false;
    }

    void remove (const K& k) {
        assert(table != NULL);
        vec<Pair>& ps = table[index(k)];
        int j = 0;
        for (; j < ps.size() && !equals(ps[j].key, k); j++);
        assert(j < ps.size());
        ps[j] = ps.last();
        ps.pop();
    }

    void clear  () {
        cap = size = 0;
        delete [] table;
        table = NULL;
    }
};

#endif