tb_hashtable.h

// ================================================================================
// ==      This file is a part of Turbo Badger. (C) 2011-2014, Emil Segerås      ==
// ==                     See tb_core.h for more information.                    ==
// ================================================================================

#ifndef TB_HASHTABLE_H
#define TB_HASHTABLE_H

#include "tb_core.h"
#include <assert.h>

namespace tb {

class TBHashTable
{
public:
    TBHashTable();
    virtual ~TBHashTable();

    void RemoveAll() { RemoveAll(false); }

    void DeleteAll() { RemoveAll(true); }

    void *Get(uint32_t key) const;

    bool Add(uint32_t key, void *content);

    void *Remove(uint32_t key);

    void Delete(uint32_t key);

    bool Rehash(uint32_t num_buckets);

    bool NeedRehash() const;

    uint32_t GetSuitableBucketsCount() const;

#ifdef TB_RUNTIME_DEBUG_INFO

    void Debug();
#endif

protected:
    virtual void DeleteContent(void * /*content*/) { assert(!"You need to subclass and implement!"); }
private:
    friend class TBHashTableIterator;
    void RemoveAll(bool delete_content);
    struct ITEM {
        uint32_t key;
        ITEM *next;
        void *content;
    } **m_buckets;
    uint32_t m_num_buckets;
    uint32_t m_num_items;
};

//FIX: make it safe in case the current item is removed from the hashtable
class TBHashTableIterator
{
public:
    TBHashTableIterator(TBHashTable *hash_table);
    void *GetNextContent();
private:
    TBHashTable *m_hash_table;
    uint32_t m_current_bucket;
    TBHashTable::ITEM *m_current_item;
};

template<class T>
class TBHashTableIteratorOf : private TBHashTableIterator
{
public:
    TBHashTableIteratorOf(TBHashTable *hash_table) : TBHashTableIterator(hash_table) {}
    T *GetNextContent() { return (T*) TBHashTableIterator::GetNextContent(); }
};

template<class T>
class TBHashTableOf : public TBHashTable
{
// FIX: Don't do public inheritance! Either inherit privately and forward, or use a private member backend!
public:
    T *Get(uint32_t key) const { return (T*) TBHashTable::Get(key); }

protected:
    virtual void DeleteContent(void *content) { delete (T*) content; }
};

template<class T>
class TBHashTableAutoDeleteOf : public TBHashTable
{
public:
    ~TBHashTableAutoDeleteOf() { DeleteAll(); }

    T *Get(uint32_t key) const { return (T*) TBHashTable::Get(key); }

protected:
    virtual void DeleteContent(void *content) { delete (T*) content; }
};

} // namespace tb

#endif // TB_HASHTABLE_H