hsearch.c revision 7c2fbfb345896881c631598ee3852ce9ce33fb07
/***********************************************************************
* *
* This software is part of the ast package *
* Copyright (c) 1985-2008 AT&T Intellectual Property *
* and is licensed under the *
* Common Public License, Version 1.0 *
* by AT&T Intellectual Property *
* *
* A copy of the License is available at *
* http://www.opensource.org/licenses/cpl1.0.txt *
* (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9) *
* *
* Information and Software Systems Research *
* AT&T Research *
* Florham Park NJ *
* *
* Glenn Fowler <gsf@research.att.com> *
* David Korn <dgk@research.att.com> *
* Phong Vo <kpv@research.att.com> *
* *
***********************************************************************/
/*
* hsearch() for systems that have <search.h> but no hsearch()
* why would such a system provide the interface but not the
* implementation? that's what happens when one slimes their
* way through standards compliance
*
* NOTE: please excuse the crude feature test
*/
#if !_UWIN
void _STUB_hsearch(){}
#else
#if _PACKAGE_ast
#include <ast.h>
#endif
#define hcreate ______hcreate
#define hdestroy ______hdestroy
#define hsearch ______hsearch
#include <search.h>
#undef hcreate
#undef hdestroy
#undef hsearch
#include "dthdr.h"
#if defined(__EXPORT__)
#define extern __EXPORT__
#endif
/* POSIX hsearch library based on libdt
** Written by Kiem-Phong Vo (AT&T Research, 07/19/95)
*/
/* type of objects in hash table */
typedef struct _hash_s
{ Dtlink_t link;
ENTRY item;
} Hash_t;
/* object delete function */
#if __STD_C
static void hashfree(Dt_t* dt, Void_t* obj, Dtdisc_t* disc)
#else
static void hashfree(dt, obj, disc)
Dt_t* dt;
Void_t* obj;
Dtdisc_t* disc;
#endif
{
free(((Hash_t*)obj)->item.key);
free(obj);
}
static Dt_t* Hashtab; /* object dictionary */
static Dtdisc_t Hashdisc = /* discipline */
{ sizeof(Dtlink_t), -1,
0,
NIL(Dtmake_f), hashfree,
NIL(Dtcompar_f), /* always use strcmp */
NIL(Dthash_f),
NIL(Dtmemory_f),
NIL(Dtevent_f)
};
extern
#if __STD_C
int hcreate(size_t nel)
#else
int hcreate(nel)
size_t nel;
#endif
{
if(Hashtab) /* already opened */
return 0;
if(!(Hashtab = dtopen(&Hashdisc,Dtset)) )
return 0;
return 1;
}
extern void hdestroy()
{ if(Hashtab)
dtclose(Hashtab);
Hashtab = NIL(Dt_t*);
}
extern
#if __STD_C
ENTRY* hsearch(ENTRY item, ACTION action)
#else
ENTRY* hsearch(item, action)
ENTRY item;
ACTION action;
#endif
{
reg Hash_t* o;
if(!Hashtab)
return NIL(ENTRY*);
if(!(o = (Hash_t*)dtmatch(Hashtab,item.key)) && action == ENTER &&
(o = (Hash_t*)malloc(sizeof(Hash_t)) ) )
{ o->item = item;
o = (Hash_t*)dtinsert(Hashtab,o);
}
return o ? &(o->item) : NIL(ENTRY*);
}
#endif