CWE-ou-minkata/Sources/Plasma/CoreLib/hsHashTable.h

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*==LICENSE==*/
// hsHashTable.h

#ifndef _hsHashTable_Included_
#define _hsHashTable_Included_

#include "hsTemplates.h"

template <class T>
class hsHashTableIterator
{
public:
    hsHashTableIterator() : fList(nil), fIndex(-1)  { }
    explicit hsHashTableIterator(hsTArray<T>* list, uint32_t idx) : fList(list), fIndex(idx) { }
    
    T* operator->() const   { return &((*fList)[fIndex]); }
    T& operator*() const    { return (*fList)[fIndex]; }
    
    hsHashTableIterator<T>& operator++()            { fIndex--; return *this; }
    const hsHashTableIterator<T>& operator++(int)   { hsHashTableIterator<T> temp(*this); --(*this); return temp; }
    
    hsHashTableIterator<T>& operator--()            { fIndex++; return *this; }
    const hsHashTableIterator<T>& operator--(int)   { hsHashTableIterator<T> temp(*this); ++(*this); return temp; }
    
    hsBool operator==(const hsHashTableIterator<T>& other) const    { return fList==other.fList && fIndex==other.fIndex; }
    hsBool operator!=(const hsHashTableIterator<T>& other) const    { return !(*this == other); }
    
private:
    hsTArray<T>* fList;
    uint32_t fIndex;
};


template <class T> 
class hsHashTable
{
public:
    hsHashTable(uint32_t size=150001, uint32_t step=1);
    ~hsHashTable();

    typedef hsHashTableIterator<T> iterator;

    iterator begin()    { return iterator(&fItemList,fItemList.Count()-1); }
    iterator end()      { return iterator(&fItemList,0); }
    void clear();

    uint32_t count()          { return fItemList.Count()-1; }
    uint32_t size()           { return fSize; }

    uint32_t CollisionCount() { return fCollisionCount; }

    inline void insert(T& item);
    inline void erase(T& item);
    inline iterator find(const T& item);

    iterator GetItem(uint32_t i);
    
private:
    hsTArray<T>         fItemList;
    hsTArray<uint32_t>    fClearList;

    uint32_t*     fHashTable;
    uint32_t      fSize;
    uint32_t      fCollisionStep;
    uint32_t      fCollisionCount;

    // No copy or assignment
    hsHashTable(const hsHashTable&);
    hsHashTable &operator=(const hsHashTable&);
};

template <class T>
hsHashTable<T>::hsHashTable(uint32_t size, uint32_t step) :
fSize(size),
fCollisionStep(step),
fCollisionCount(0)
{
    fItemList.SetCount(1);
    fHashTable = new uint32_t[fSize];
    memset(fHashTable,0,fSize*sizeof(uint32_t));
}

template <class T>
hsHashTable<T>::~hsHashTable()
{
    delete [] fHashTable;
}

template <class T>
void hsHashTable<T>::clear()
{
    fItemList.SetCount(1);
    for (int32_t i=0; i<fClearList.Count(); i++)
        fHashTable[ fClearList[i] ] = 0;
    fClearList.Reset();
}

template <class T>
void hsHashTable<T>::insert(T& item)
{
    hsAssert(fClearList.Count() < fSize,"Hash table overflow!  Increase the table size.");
    uint32_t h = item.GetHash();
    h %= fSize;
    while (uint32_t it = fHashTable[h])
    {
        if ( fItemList[it] == item)
        {
            fItemList[it] = item;
            return;
        }
        h += fCollisionStep;
        h %= fSize;
        fCollisionCount++;
    }
    fHashTable[h] = fItemList.Count();
    fItemList.Append(item);
    fClearList.Append(h);
}

template <class T>
void hsHashTable<T>::erase(T& item)
{
    uint32_t h = item.GetHash();
    h %= fSize;
    while (uint32_t it = fHashTable[h])
    {
        if ( fItemList[it] == item )
        {
            fHashTable[h] = 0;
            return;
        }
    }
}

template <class T>
hsHashTableIterator<T> hsHashTable<T>::find(const T& item)
{
    uint32_t h = item.GetHash();
    h %= fSize;
    while (uint32_t it = fHashTable[h])
    {
        if ( fItemList[it] == item )
        {
            return iterator(&fItemList,it);
        }
        h += fCollisionStep;
        h %= fSize;
        fCollisionCount++;
    }
    return end();
}

template <class T>
hsHashTableIterator<T> hsHashTable<T>::GetItem(uint32_t i)
{
    return iterator(&fItemList,i+1);
}

#endif // _hsHashTable_Included_