/* LIBDGL -- a Directed Graph Library implementation
 * Copyright (C) 2002 Roberto Micarelli
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

/* best view tabstop=4
 */
#include <stdio.h>
#include <stdlib.h>

#include "type.h"
#include "heap.h"



void dglHeapInit( dglHeap_s * pheap )
{
	pheap->index = 0;
	pheap->count = 0;
	pheap->block = 256;
	pheap->pnode = NULL;
}

void dglHeapFree( dglHeap_s * pheap, dglHeapCancelItem_fn pfnCancelItem  )
{
	int iItem;
	if ( pheap->pnode ) {
		if ( pfnCancelItem ) {
			for (iItem = 0 ; iItem <= pheap->index ; iItem ++) {
				pfnCancelItem(pheap, & pheap->pnode[iItem] );
			}
		}
		free( pheap->pnode );
	}
	pheap->pnode = NULL;
}

int dglHeapInsertMin(
		dglHeap_s * pheap ,
		long key ,
		unsigned char flags ,
		dglHeapData_u value
		)
{
	long i;

	if ( pheap->index >= pheap->count - 1 )
	{
		pheap->count += pheap->block;
		if ( (pheap->pnode = realloc( pheap->pnode , sizeof( dglHeapNode_s ) * pheap->count )) == NULL ) return -1;
	}

	i = ++pheap->index;

	while( i != 1 && key < pheap->pnode[ i / 2 ].key )
	{
		pheap->pnode[ i ] = pheap->pnode[ i / 2 ];
		i /= 2;
	}

	pheap->pnode[ i ].key = key;
	pheap->pnode[ i ].flags = flags;
	pheap->pnode[ i ].value = value;

	return i;
}

int dglHeapExtractMin(
		dglHeap_s * pheap,
		dglHeapNode_s * pnoderet
		)
{
	dglHeapNode_s temp;
	long iparent , ichild;

	if ( pheap->index == 0 ) return 0; /* empty heap */

	*pnoderet = pheap->pnode[ 1 ];

	temp = pheap->pnode[ pheap->index-- ];
	
	iparent = 1;
	ichild = 2;

	while( ichild <= pheap->index )
	{
		if ( ichild < pheap->index && pheap->pnode[ ichild ].key > pheap->pnode[ ichild + 1 ].key )
		{
			ichild ++;
		}
		if ( temp.key <= pheap->pnode[ ichild ].key ) break;

		pheap->pnode[ iparent ] = pheap->pnode[ ichild ];
		iparent = ichild;
		ichild *= 2;
	}
	pheap->pnode[ iparent ] = temp;

	return 1;	
}

int dglHeapInsertMax(
		dglHeap_s * pheap ,
		long key ,
		unsigned char flags ,
		dglHeapData_u value
		)
{
	long i;

	if ( pheap->index >= pheap->count - 1 )
	{
		pheap->count += pheap->block;
		if ( (pheap->pnode = realloc( pheap->pnode , sizeof( dglHeapNode_s ) * pheap->count )) == NULL ) return -1;
	}

	i = ++pheap->index;

	while( i != 1 && key > pheap->pnode[ i / 2 ].key )
	{
		pheap->pnode[ i ] = pheap->pnode[ i / 2 ];
		i /= 2;
	}

	pheap->pnode[ i ].key = key;
	pheap->pnode[ i ].flags = flags;
	pheap->pnode[ i ].value = value;

	return i;
}

int dglHeapExtractMax(
		dglHeap_s * pheap,
		dglHeapNode_s * pnoderet
		)
{
	dglHeapNode_s temp;
	long iparent , ichild;

	if ( pheap->index == 0 ) return 0; /* empty heap */

	*pnoderet = pheap->pnode[ 1 ];

	temp = pheap->pnode[ pheap->index-- ];
	
	iparent = 1;
	ichild = 2;

	while( ichild <= pheap->index )
	{
		if ( ichild < pheap->index && pheap->pnode[ ichild ].key < pheap->pnode[ ichild + 1 ].key )
		{
			ichild ++;
		}
		if ( temp.key >= pheap->pnode[ ichild ].key ) break;

		pheap->pnode[ iparent ] = pheap->pnode[ ichild ];
		iparent = ichild;
		ichild *= 2;
	}
	pheap->pnode[ iparent ] = temp;

	return 1;
}

