/*

 *  Hash.h

 *  Ottoman

 *

 *  Created by Jens Alfke on 8/20/09.

 *  Copyright 2009 Jens Alfke. All rights reserved.

 *  BSD-Licensed: See the file "LICENSE.txt" for details.

 */

#ifndef _MOOSEYARD_HASH_

#define _MOOSEYARD_HASH_

#include "Base.h"

#include "Dictionary.h"

namespace Mooseyard {

    /** A fairly low-level hash-table class whose keys and values are arbitrary data blobs.

        This class does no memory management of the keys and values: the memory ranges

        pointed to by the key and value parameters to put() must remain valid as long as

        that key or value remains in the hash-table. */

    class Hash {

    public:

        typedef void* Value;

        /** Creates a new, empty Hash. */

        explicit Hash (int capacity = 50);

        ~Hash();

        /** Gets the value associated with the given key. */

        Value get(Key) const;

        Value operator[] (Key key) const                        {return get(key);}

        /** Returns the number of values in the Hash. */

        int count() const                                       {return _count;}

        /** Sets the given value for the given key, replacing any existing value. */

        void put(Key, Value);

        /** Removes the value with the given key. Returns the former value, or NULL if not found. */

        Value remove(Key);

        /** Removes all values. */

        void removeAll();

        void dump() const;

        class IndexEntry;

        class Iterator {

        public:

            Iterator (const Hash *h);

            Iterator (const Hash &h);

            operator bool() const                           {return hasValue();}

            Value operator*() const                         {return value();}

            Iterator& operator++()                          {next(); return *this;}

            Key key() const;

            Value value() const;

            bool hasValue() const                           {return _entry < _end;}

            bool next();

        private:

            Iterator (IndexEntry *start, IndexEntry*end);

            IndexEntry* _entry;

            IndexEntry* const _end;

            UNCOPYABLE(Iterator);

        };

    private:

        IndexEntry& _find (Key key) const;

        IndexEntry& _findForPut (const IndexEntry &newEntry);

        void _resize(int newSize);

        void _read();

        UNCOPYABLE(Hash);

        int _count;

        int _tableSize;

        IndexEntry *_table;

        friend class Iterator;

    };

    /** A concrete Dictionary implemented with a Hash. */

    class HashDictionary :public MutableDictionary {

    public:

        explicit HashDictionary (int capacity =50)  :_hash(capacity) { }

        virtual ~HashDictionary();

        virtual int count() const                   {return _hash.count();}

        virtual bool contains (Key) const;

        virtual Blob get (Key key) const            {return _convertValue(_hash.get(key));}

        virtual void put (Key, Blob value);

        virtual bool remove (Key);

        virtual void removeAll();

        virtual Iterator* iterate() const           {return new Iterator(*this);}

        class Iterator :public Dictionary::Iterator {

        public:

            explicit Iterator (const HashDictionary &d)      :_it(d._hash) { }

            virtual Key key() const                 {return _it.key();}

            virtual Blob value() const              {return _convertValue(_it.value());}

            virtual bool hasValue() const           {return _it.hasValue();}

            virtual bool next()                     {return _it.next();}

        private:

            Hash::Iterator _it;

        };

    private:

        static Blob _convertValue (void*);

        Hash _hash;

        friend class Iterator;

    };

}

#endif _MOOSEYARD_HASH_