Files
harbour-core/harbour/source/common/hash.c
2000-07-16 15:37:11 +00:00

256 lines
6.9 KiB
C

/*
* $Id$
*/
/*
* Harbour Project source code:
* Harbour simple hash table implementation
*
* Copyright 1999 Ryszard Glab <rglab@imid.med.pl>
* www - http://www.harbour-project.org
*
* 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, with one exception:
*
* The exception is that if you link the Harbour Runtime Library (HRL)
* and/or the Harbour Virtual Machine (HVM) with other files to produce
* an executable, this does not by itself cause the resulting executable
* to be covered by the GNU General Public License. Your use of that
* executable is in no way restricted on account of linking the HRL
* and/or HVM code into it.
*
* 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., 675 Mass Ave, Cambridge, MA 02139, USA (or visit
* their web site at http://www.gnu.org/).
*
*/
#include "hbhash.h"
static HB_HASH_ITEM_PTR hb_hashItemNew( ULONG ulKey, void * pValue )
{
HB_HASH_ITEM_PTR pItem = (HB_HASH_ITEM_PTR) hb_xgrab( sizeof( HB_HASH_ITEM ) );
pItem->key = ulKey;
pItem->cargo = pValue;
pItem->next = NULL;
return pItem;
}
static void hb_hashItemDelete( HB_HASH_ITEM_PTR pItem )
{
hb_xfree( (void *) pItem );
}
/* create a new hash table
* ulSize = initial numer of items in the table
* pHashTable = a function that calculates a hash key value
* (first parameter is a value to add)
* pDelete = a function that clears item's value before item's releasing
* (first parameter is a value to clear)
* pComp = a function for comparing a values
* (first and second are values to compare, function have to return
* zero if values match or nonzero if they don't match)
*/
HB_HASH_TABLE_PTR hb_hashTableCreate( ULONG ulSize,
HB_HASH_FUNC_PTR pHashFunc,
HB_HASH_FUNC_PTR pDelete,
HB_HASH_FUNC_PTR pComp )
{
HB_HASH_TABLE_PTR pTable = ( HB_HASH_TABLE_PTR ) hb_xgrab( sizeof( HB_HASH_TABLE ) );
pTable->ulTableSize = ulSize;
pTable->pKeyFunc = pHashFunc;
pTable->pDeleteItemFunc = pDelete;
pTable->pCompFunc = pComp;
pTable->ulCount = pTable->ulUsed = 0;
pTable->pItems = ( HB_HASH_ITEM_PTR * ) hb_xgrab( sizeof( HB_HASH_ITEM_PTR ) * ulSize );
memset( pTable->pItems, 0, sizeof( HB_HASH_ITEM_PTR ) * ulSize );
return pTable;
}
/* Delete all items in the hash table and next delete the table
*/
void hb_hashTableKill( HB_HASH_TABLE_PTR pTable )
{
ULONG ulSize = 0;
while( ulSize < pTable->ulTableSize )
{
if( pTable->pItems[ ulSize ] )
{
HB_HASH_ITEM_PTR pItem;
HB_HASH_ITEM_PTR pNext;
pItem = pTable->pItems[ ulSize ];
while( pItem )
{
if( pTable->pDeleteItemFunc )
( pTable->pDeleteItemFunc )( pItem->cargo, NULL );
pNext = pItem->next;
hb_xfree( ( void * ) pItem );
pItem = pNext;
}
}
++ulSize;
}
hb_xfree( ( void * ) pTable->pItems );
hb_xfree( ( void * ) pTable );
}
/* resize table */
HB_HASH_TABLE_PTR hb_hashTableResize( HB_HASH_TABLE_PTR pTable, ULONG ulNewSize )
{
HB_HASH_TABLE_PTR pNew;
ULONG ulSize = 0;
if( ulNewSize == 0 )
ulNewSize = 2 * pTable->ulTableSize + 1;
pNew = hb_hashTableCreate( ulNewSize,
pTable->pKeyFunc,
pTable->pDeleteItemFunc,
pTable->pCompFunc );
while( ulSize < pTable->ulTableSize )
{
if( pTable->pItems[ ulSize ] )
{
HB_HASH_ITEM_PTR pItem;
pItem = pTable->pItems[ ulSize ];
while( pItem )
{
ULONG ulKey;
HB_HASH_ITEM_PTR pNewItem, pNext;
pNext = pItem->next;
ulKey = ( pTable->pKeyFunc )( pItem->cargo, NULL );
pNewItem = pNew->pItems[ ulKey ];
if( pNewItem )
{
while( pNewItem->next )
pNewItem = pNewItem->next;
pNewItem->next = pItem;
}
else
{
pNew->pItems[ ulKey ] = pItem;
++pNew->ulUsed;
}
pItem->key = ulKey;
pItem->next = NULL;
++pNew->ulCount;
pItem = pNext;
}
}
++ulSize;
}
hb_xfree( ( void * ) pTable->pItems );
hb_xfree( ( void * ) pTable );
return pNew;
}
/* add a new value into th ehash table */
BOOL hb_hashTableAdd( HB_HASH_TABLE_PTR pTable, void *pValue )
{
ULONG ulKey;
HB_HASH_ITEM_PTR pItem;
ulKey = ( pTable->pKeyFunc )( pValue, NULL );
pItem = pTable->pItems[ ulKey ];
if( pItem )
{
while( pItem->next )
pItem = pItem->next;
pItem->next = hb_hashItemNew( ulKey, pValue );
}
else
{
pTable->pItems[ ulKey ] = hb_hashItemNew( ulKey, pValue );
++pTable->ulUsed;
}
++pTable->ulCount;
return TRUE;
}
/* return the pointer to item's value or NULL if not found
*/
void * hb_hashTableFind( HB_HASH_TABLE_PTR pTable, void *pValue )
{
ULONG ulKey;
HB_HASH_ITEM_PTR pItem;
void * pFound = NULL;
ulKey = ( pTable->pKeyFunc )( pValue, NULL );
pItem = pTable->pItems[ ulKey ];
if( pItem )
{
while( pItem && (( pTable->pCompFunc )( pItem->cargo, pValue ) != 0) )
pItem = pItem->next;
if( pItem )
pFound = pItem->cargo;
}
return pFound;
}
/* Delete an item from the table
* Returns TRUE if item was found and returns FALSE when passed item
* is not stored in the table
*/
BOOL hb_hashTableDel( HB_HASH_TABLE_PTR pTable, void *pValue )
{
ULONG ulKey;
HB_HASH_ITEM_PTR pItem;
HB_HASH_ITEM_PTR pPrev = NULL;
BOOL bFound = FALSE;
ulKey = ( pTable->pKeyFunc )( pValue, NULL );
pItem = pTable->pItems[ ulKey ];
while( pItem && !bFound )
{
if( ( pTable->pCompFunc )( pItem->cargo, pValue ) == 0 )
{
if( pPrev )
pPrev->next = pItem->next;
else
{
pTable->pItems[ ulKey ] = pItem->next;
if( !pItem->next )
--pTable->ulUsed;
}
hb_hashItemDelete( pItem );
bFound = TRUE;
--pTable->ulCount;
}
else
{
pPrev = pItem;
pItem = pItem->next;
}
}
return bFound;
}
/* return the hash table size */
ULONG hb_hashTableSize( HB_HASH_TABLE_PTR pTable )
{
return pTable->ulTableSize;
}