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cdesktopenv/cde/lib/DtSvc/DtUtil2/Hash.c

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/*
* CDE - Common Desktop Environment
*
* Copyright (c) 1993-2012, The Open Group. All rights reserved.
*
* These libraries and programs are free software; you can
* redistribute them and/or modify them under the terms of the GNU
* Lesser General Public License as published by the Free Software
* Foundation; either version 2 of the License, or (at your option)
* any later version.
*
* These libraries and programs are distributed in the hope that
* they will be useful, but WITHOUT ANY WARRANTY; without even the
* implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
* PURPOSE. See the GNU Lesser General Public License for more
* details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with these librararies and programs; if not, write
* to the Free Software Foundation, Inc., 51 Franklin Street, Fifth
* Floor, Boston, MA 02110-1301 USA
*/
/* $XConsortium: Hash.c /main/4 1995/10/26 15:22:41 rswiston $ */
/*
* (c) Copyright 1993, 1994 Hewlett-Packard Company *
* (c) Copyright 1993, 1994 International Business Machines Corp. *
* (c) Copyright 1993, 1994 Sun Microsystems, Inc. *
* (c) Copyright 1993, 1994 Novell, Inc. *
*/
/***********************************************************
Copyright 1987, 1988, 1990 by Digital Equipment Corporation, Maynard,
Massachusetts, and the Massachusetts Institute of Technology, Cambridge,
Massachusetts.
All Rights Reserved
Permission to use, copy, modify, and distribute this software and its
documentation for any purpose and without fee is hereby granted,
provided that the above copyright notice appear in all copies and that
both that copyright notice and this permission notice appear in
supporting documentation, and that the names of Digital or MIT not be
used in advertising or publicity pertaining to distribution of the
software without specific, written prior permission.
DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
DIGITAL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
SOFTWARE.
******************************************************************/
#include "HashP.h"
/******** Static Function Declarations ********/
static unsigned int GetTableIndex(
register DtHashTable tab,
register DtHashKey key,
#if NeedWidePrototypes
register int new) ;
#else
register Boolean new) ;
#endif /* NeedWidePrototypes */
static void ExpandHashTable(
register DtHashTable tab) ;
/******** End Static Function Declarations ********/
typedef unsigned long Signature;
typedef struct _DtHashTableRec {
unsigned int mask; /* size of hash table - 1 */
unsigned int rehash; /* mask - 2 */
unsigned int occupied; /* number of occupied entries */
unsigned int fakes; /* number occupied by DTHASHfake */
DtHashEntryType *types; /* lookup methods for key */
unsigned short numTypes; /* number of lookup methods */
Boolean keyIsString; /* whether the hash key is a string */
DtHashEntry *entries; /* the entries */
}DtHashTableRec;
static DtHashEntryRec DtHashfake; /* placeholder for deletions */
#define HASH(tab,sig) ((sig) & tab->mask)
#define REHASHVAL(tab, idx) ((((idx) % tab->rehash) + 2) | 1)
#define REHASH(tab,idx,rehash) ((idx + rehash) & tab->mask)
#define KEY(tab, entry) \
((* (tab->types[entry->hash.type]->hash.getKeyFunc) ) \
(entry, tab->types[entry->hash.type]->hash.getKeyClientData))
#define RELEASE_KEY(tab, entry, key) \
{\
if (tab->types[entry->hash.type]->hash.releaseKeyProc) \
(* (tab->types[entry->hash.type]->hash.releaseKeyProc)) \
(entry, key); \
}
static unsigned int
GetTableIndex(
register DtHashTable tab,
register DtHashKey key,
#if NeedWidePrototypes
register int new)
#else
register Boolean new)
#endif /* NeedWidePrototypes */
{
register DtHashEntry *entries = tab->entries;
register int len, idx, i, rehash = 0;
register char c;
register Signature sig = 0;
register DtHashEntry entry;
String s1, s2;
DtHashKey compKey;
if (tab->keyIsString) {
s1 = (String)key;
for (s2 = (char *)s1; c = *s2++; )
sig = (sig << 1) + c;
len = s2 - s1 - 1;
}
else
sig = (Signature)key;
idx = HASH(tab, sig);
while (entry = entries[idx]) {
if (entries[idx] == &DtHashfake) {
if (new)
return idx;
else
goto nomatch;
}
if (tab->keyIsString) {
compKey = KEY(tab, entry);
for (i = len, s1 = (String)key, s2 = (String) compKey;
--i >= 0; ) {
if (*s1++ != *s2++)
goto nomatch;
}
}
else {
if ((compKey = KEY(tab, entry)) != key)
s2 = " ";
else
s2 = "";
}
if (*s2) {
nomatch:
RELEASE_KEY(tab, entry, compKey);
if (!rehash)
rehash = REHASHVAL(tab, idx);
idx = REHASH(tab, idx, rehash);
continue;
}
else
RELEASE_KEY(tab, entry, compKey);
break;
}
return idx;
}
void
_DtRegisterHashEntry(
register DtHashTable tab,
register DtHashKey key,
register DtHashEntry entry )
{
unsigned int idx;
if ((tab->occupied + (tab->occupied >> 2)) > tab->mask)
ExpandHashTable(tab);
idx = GetTableIndex(tab, key, True);
if (tab->entries[idx] == &DtHashfake)
tab->fakes--;
tab->occupied++;
tab->entries[idx] = entry;
}
void
_DtUnregisterHashEntry(
register DtHashTable tab,
register DtHashEntry entry )
{
register int idx, rehash;
register DtHashEntry *entries = tab->entries;
DtHashKey key = KEY(tab, entry);
idx = GetTableIndex(tab, key, False);
RELEASE_KEY(tab, entry, key);
entries[idx] = &DtHashfake;
tab->fakes++;
tab->occupied--;
}
static void
ExpandHashTable(
register DtHashTable tab )
{
unsigned int oldmask;
register DtHashEntry *oldentries, *entries;
register int oldidx, newidx, rehash, len;
register DtHashEntry entry;
register DtHashKey key;
oldmask = tab->mask;
oldentries = tab->entries;
tab->fakes = 0;
if ((tab->occupied + (tab->occupied >> 2)) > tab->mask) {
tab->mask = (tab->mask << 1) + 1;
tab->rehash = tab->mask - 2;
}
entries = tab->entries = (DtHashEntry *) XtCalloc(tab->mask+1, sizeof(DtHashEntry));
for (oldidx = 0; oldidx <= oldmask; oldidx++) {
if ((entry = oldentries[oldidx]) && entry != &DtHashfake) {
newidx = GetTableIndex(tab, key = KEY(tab, entry), True);
RELEASE_KEY(tab, entry, key);
entries[newidx] = entry;
}
}
XtFree((char *)oldentries);
}
DtHashEntry
_DtEnumerateHashTable(
register DtHashTable tab,
register DtHashEnumerateFunc enumFunc,
register XtPointer clientData )
{
register unsigned int i;
for (i = 0; i <= tab->mask; i++)
if (tab->entries[i] &&
tab->entries[i] != &DtHashfake &&
((*enumFunc) (tab->entries[i], clientData)))
return tab->entries[i];
return NULL;
}
DtHashEntry
_DtKeyToHashEntry(
register DtHashTable tab,
register DtHashKey key )
{
register int idx, rehash, len;
register DtHashEntry entry, *entries = tab->entries;
if (!key) return NULL;
idx = GetTableIndex(tab, key, False);
return entries[idx];
}
DtHashTable
_DtAllocHashTable(DtHashEntryType *hashEntryTypes,
Cardinal numHashEntryTypes,
#if NeedWidePrototypes
int keyIsString)
#else
Boolean keyIsString)
#endif /* NeedWidePrototypes */
{
register DtHashTable tab;
tab = (DtHashTable) XtMalloc(sizeof(struct _DtHashTableRec));
tab->types = hashEntryTypes;
tab->numTypes = numHashEntryTypes;
tab->keyIsString = keyIsString;
tab->mask = 0x7f;
tab->rehash = tab->mask - 2;
tab->entries = (DtHashEntry *) XtCalloc(tab->mask+1, sizeof(DtHashEntry));
tab->occupied = 0;
tab->fakes = 0;
return tab;
}
void
_DtFreeHashTable(
DtHashTable hashTable )
{
XtFree((char *)hashTable->entries);
XtFree((char *)hashTable);
}
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