/*
THE COMPUTER CODE CONTAINED HEREIN IS THE SOLE PROPERTY OF PARALLAX
SOFTWARE CORPORATION ("PARALLAX").  PARALLAX, IN DISTRIBUTING THE CODE TO
END-USERS, AND SUBJECT TO ALL OF THE TERMS AND CONDITIONS HEREIN, GRANTS A
ROYALTY-FREE, PERPETUAL LICENSE TO SUCH END-USERS FOR USE BY SUCH END-USERS
IN USING, DISPLAYING,  AND CREATING DERIVATIVE WORKS THEREOF, SO LONG AS
SUCH USE, DISPLAY OR CREATION IS FOR NON-COMMERCIAL, ROYALTY OR REVENUE
FREE PURPOSES.  IN NO EVENT SHALL THE END-USER USE THE COMPUTER CODE
CONTAINED HEREIN FOR REVENUE-BEARING PURPOSES.  THE END-USER UNDERSTANDS
AND AGREES TO THE TERMS HEREIN AND ACCEPTS THE SAME BY USE OF THIS FILE.  
COPYRIGHT 1993-1998 PARALLAX SOFTWARE CORPORATION.  ALL RIGHTS RESERVED.
*/
/*
 * $Source: f:/miner/source/main/rcs/hash.c $
 * $Revision: 2.0 $
 * $Author: john $
 * $Date: 1995/02/27 11:28:01 $
 * 
 * Functions to do hash table lookup.
 * 
 * $Log: hash.c $
 * Revision 2.0  1995/02/27  11:28:01  john
 * New version 2.0, which has no anonymous unions, builds with
 * Watcom 10.0, and doesn't require parsing BITMAPS.TBL.
 * 
 * Revision 1.5  1994/12/05  23:37:06  matt
 * Took out calls to warning() function
 * 
 * Revision 1.4  1994/05/09  20:02:33  john
 * Fixed bug w/ upper/lower case.
 * 
 * Revision 1.3  1994/05/06  15:31:51  john
 * Don't add duplicate names to the hash table.
 * 
 * Revision 1.2  1994/05/03  16:45:35  john
 * Added hash table lookup to speed up loading.
 * 
 * Revision 1.1  1994/05/03  10:36:41  john
 * Initial revision
 * 
 * 
 */

#pragma off (unreferenced)
static char rcsid[] = "$Id: hash.c 2.0 1995/02/27 11:28:01 john Exp $";
#pragma on (unreferenced)

#include <stdlib.h>
#include <stdio.h>
#include <string.h>

#include "error.h"
#include "mono.h"
#include "hash.h"
#include "key.h"
	
int hashtable_init( hashtable *ht, int size )	{
	int i;

	ht->size=0;

	for (i=1; i<12; i++ )	{
		if ( (1<<i) >= size )	{
			ht->bitsize = i;
			ht->size = 1<<i;
			break;
		}
	}
	size = ht->size;
	ht->and_mask = ht->size - 1;
	if (ht->size==0)
		Error( "Hashtable has size of 0" );

	ht->key = (char **)malloc( size * sizeof(char *) );
	if (ht->key==NULL)
		Error( "Not enough memory to create a hash table of size %d", size );

	for (i=0; i<size; i++ )
		ht->key[i] = NULL;

	// Use calloc cause we want zero'd array.
	ht->value = malloc( size*sizeof(int) );
	if (ht->value==NULL)	{
		free(ht->key);
		Error( "Not enough memory to create a hash table of size %d\n", size );
	}

	ht->nitems = 0;

	return 0;
}

void hashtable_free( hashtable *ht )	{
	if (ht->key != NULL )
		free( ht->key );
	if (ht->value != NULL )
		free( ht->value );
	ht->size = 0;
}

int hashtable_getkey( char *key )	{
	int k = 0, i=0;

	while( *key )	{
		k^=((int)(*key++))<<i;
		i++;
	}
	return k;
}

int hashtable_search( hashtable *ht, char *key )	{
	int i,j,k;

	strlwr( key );

	k = hashtable_getkey( key );
	i = 0;
	
	while(i < ht->size )	{
		j = (k+(i++)) & ht->and_mask;
		if ( ht->key[j] == NULL )
			return -1;
		if (!stricmp(ht->key[j], key ))
			return ht->value[j];
	}
	return -1;
}

void hashtable_insert( hashtable *ht, char *key, int value )	{
	int i,j,k;

//	mprintf( 0, "Inserting '%s' into hash table\n", key );
//	key_getch();

	strlwr( key );
	k = hashtable_getkey( key );
	i = 0;

	while(i < ht->size)	{
		j = (k+(i++)) & ht->and_mask;
//		Assert( j < ht->size );
//		mprintf( 0, "Word '%s' (%d) at level %d has value of %d\n", key, k, i-1, j );
//		mprintf( 0, "ht->key[%d]=%.8x\n", j, ht->key[j] );
		if ( ht->key[j] == NULL )	{
			ht->nitems++;
			ht->key[j] = key;
			ht->value[j] = value;
			return;
		} else if (!stricmp( key, ht->key[j] ))	{
			return;
		}
	}
	Error( "Out of hash slots\n" );
}