/*----------------------------------------------------------------------------*/
/*                                                                            */
/* Copyright (c) 1995, 2004 IBM Corporation. All rights reserved.             */
/* Copyright (c) 2005-2014 Rexx Language Association. All rights reserved.    */
/*                                                                            */
/* This program and the accompanying materials are made available under       */
/* the terms of the Common Public License v1.0 which accompanies this         */
/* distribution. A copy is also available at the following address:           */
/* https://www.oorexx.org/license.html                                        */
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/* without modification, are permitted provided that the following            */
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/*                                                                            */
/* Neither the name of Rexx Language Association nor the names                */
/* of its contributors may be used to endorse or promote products             */
/* derived from this software without specific prior written permission.      */
/*                                                                            */
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/*                                                                            */
/*----------------------------------------------------------------------------*/
/******************************************************************************/
/*                                                                            */
/* Mapping table for pointer index to an object value.  Used for the object   */
/* memory allocation tables.                                                  */
/*                                                                            */
/******************************************************************************/
#ifndef Included_PointerBucket
#define Included_PointerBucket

#include "ObjectClass.hpp"


/**
 * A mapping class for mapping pointer values to an associated
 * object instance.
 */
class PointerBucket : public RexxInternalObject
{
 friend class PointerTable;
 public:
    typedef size_t MapLink;                  // a link to another map item

           void *operator new(size_t base, size_t entries);
    inline void  operator delete(void *) {;}

    PointerBucket(size_t entries);
    inline PointerBucket(RESTORETYPE restoreType) { ; };

    void live(size_t) override;
    void liveGeneral(MarkReason reason) override;

    void         empty();
    bool         isEmpty() { return itemCount == 0; }
    bool         isFull()  { return itemCount >= totalSize; }
    size_t       items() { return itemCount; };

    RexxInternalObject *remove(void *key);
    RexxInternalObject *get(void *key);
    bool         put(RexxInternalObject *value, void *key);
    bool         hasIndex(void *key);
    void         merge(PointerBucket *other);
    MapLink      locate(void *key);
    bool         append(RexxInternalObject *value, void *index, MapLink position);

    // We never get saved in the image or flattened with other objects, so we can just use the
    // identity hash to generate the index
    inline MapLink hashIndex(void *index) { return (MapLink)(((uintptr_t)index) % bucketSize); }

    // link terminator
    static const MapLink NoMore = 0;
    // indicates not linked
    static const MapLink NoLink = ~((MapLink)0);

protected:

   class MapEntry
   {
   public:
       void *index;                 // the value we index from
       RexxInternalObject *value;   // the stored value
       MapLink next;                // next item in overflow bucket

       inline bool isAvailable() { return index == NULL; }
       inline bool isIndex(void *i) { return i == index; }
       inline void clear() { set(NULL, OREF_NULL); next = NoMore; }
       inline void copyElement(MapEntry &other)
       {
           value = other.value;
           index = other.index;
           next = other.next;
       }
       // NOTE:  This is a transient object, no setField() used.
       inline void set(void *i, RexxInternalObject *v) { index = i; value = v; }
       inline void setValue(RexxInternalObject *v) { value = v; }
   };

    size_t   bucketSize;                // size of the hash table
    size_t   totalSize;                 // total size of the table, including the overflow area
    size_t   itemCount;                 // total number of items in the table
    MapLink  freeItem;                  // first free element
    MapEntry entries[1];                // hash table entries
};

#endif