//  ============================================================
//
//  subHeap.h
//
//  Copyright 2002, Dennis Meilicke and Rene Peralta
//
//  ============================================================
//
//  Description:
//
//  Implementation of the sub-heap allocator.
//
//  ============================================================
#ifndef __ln3_subHeap__
#define __ln3_subHeap__


#include <iostream>
using namespace std;

template<class OBJ>
class SubHeapAllocator
{
private:
    OBJ *block;
    OBJ *endOfBlock;
    OBJ *nextBase;
    OBJ *freeBase;

    size_t quanta;

public:
    SubHeapAllocator( )
    {
        block = 0;
        endOfBlock = 0;
        nextBase = (OBJ *)1;
        freeBase = 0;
        quanta = 10000;
    }

    OBJ *allocate( void )
    {
        OBJ *ret;

        if( freeBase )
        {
            ret = freeBase;
            freeBase = *( (OBJ **)freeBase );
        }
        else
        {
            if( nextBase > endOfBlock )
            {
                //
                //  allocate enough for 'quanta' Bases, plus one void pointer
                //  for the block list.
                //
                OBJ *newBlock = (OBJ *)(new char[ sizeof( void * ) + ( sizeof(OBJ) * quanta ) ]);
                *( (OBJ **)newBlock ) = block;
                block = newBlock;
                nextBase = (OBJ *)( (char *)block + sizeof( void * ) );
                endOfBlock = block + quanta;
            }
            
            ret = nextBase;
            nextBase++;
        }

        return ret;
    }

    void deallocate( OBJ *x )
    {
        *((OBJ **)x) = freeBase;
        freeBase = x;
    }

    inline size_t getQuanta( void ) { return quanta; }
    inline void   setQuanta( size_t q ) { quanta = q; }
};


#endif