dbm.c

<B>Digital的Unix操作系统VAX 4.2源码</B>

#ifndef lint
static char *sccsid = "@(#)dbm.c	4.1	ULTRIX	7/2/90";
#endif lint

/*
 *			Copyright (c) 1989 by
 *		Digital Equipment Corporation, Maynard, MA
 *			All rights reserved.
 *								
 *	This software is furnished under a license and may be used and
 *	copied  only  in accordance with the terms of such license and
 *	with the  inclusion  of  the  above  copyright  notice.   This
 *	software  or  any  other copies thereof may not be provided or
 *	otherwise made available to any other person.  No title to and
 *	ownership of the software is hereby transferred.		
 *								
 *	This software is  derived  from  software  received  from  the
 *	University    of   California,   Berkeley,   and   from   Bell
 *	Laboratories.  Use, duplication, or disclosure is  subject  to
 *	restrictions  under  license  agreements  with  University  of
 *	California and with AT&T.					
 *								
 *	The information in this software is subject to change  without
 *	notice  and should not be construed as a commitment by Digital
 *	Equipment Corporation.					
 *								
 *	Digital assumes no responsibility for the use  or  reliability
 *	of its software on equipment which is not supplied by Digital.
 */

/*
 * Copyright (c) 1980 Regents of the University of California.
 * All rights reserved.  The Berkeley software License Agreement
 * specifies the terms and conditions for redistribution.
 *
 *  "dbm.c	5.3 (Berkeley) 85/08/15";
 */

/*
 *	Modification History
 *
 *	11/13/89	J.Friedman
 *	Replaced dbm.[ch] with new 4.3 dbm.[ch] based on ndbm calls
 *	Note only use include/dbm.h source now, not libdbm/dbm.h
 *
 *	11/16/89	J.Friedman
 *	Added dbmclose() for backward compatibility, even though undoumented 
 */

#include	<dbm.h>

#define	NODB	((DBM *)0)

static DBM *cur_db = NODB;

static char no_db[] = "dbm: no open database\n";

dbminit(file)
	char *file;
{
	if (cur_db != NODB)
		dbm_close(cur_db);

	cur_db = dbm_open(file, 2, 0);
	if (cur_db == NODB) {
		cur_db = dbm_open(file, 0, 0);
		if (cur_db == NODB)
			return (-1);
	}
	return (0);
}

int
dbmclose()
{
	dbm_close(cur_db);
	return(0);
}

long
forder(key)
datum key;
{
	if (cur_db == NODB) {
		printf(no_db);
		return (0L);
	}
	return (dbm_forder(cur_db, key));
}

datum
fetch(key)
datum key;
{
	datum item;

	if (cur_db == NODB) {
		printf(no_db);
		item.dptr = 0;
		return (item);
	}
	return (dbm_fetch(cur_db, key));
}

delete(key)
datum key;
{
	if (cur_db == NODB) {
		printf(no_db);
		return (-1);
	}
	if (dbm_rdonly(cur_db))
		return (-1);
	return (dbm_delete(cur_db, key));
}

store(key, dat)
datum key, dat;
{
	if (cur_db == NODB) {
		printf(no_db);
		return (-1);
	}
	if (dbm_rdonly(cur_db))
		return (-1);

	return (dbm_store(cur_db, key, dat, DBM_REPLACE));
}

datum
firstkey()
{
	datum item;

	if (cur_db == NODB) {
		printf(no_db);
		item.dptr = 0;
		return (item);
	}
	return (dbm_firstkey(cur_db));
}

datum
nextkey(key)
datum key;
{
	datum item;

	if (cur_db == NODB) {
		printf(no_db);
		item.dptr = 0;
		return (item);
	}
	return (dbm_nextkey(cur_db, key));
}