BSD 4_3_Net_2 release

[unix-history] / usr / src / usr.bin / m4 / look.c

/*
* Copyright (c) 1989 The Regents of the University of California.
* All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Ozan Yigit.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
*    must display the following acknowledgement:
*      This product includes software developed by the University of
*      California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
*    may be used to endorse or promote products derived from this software
*    without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/

#ifndef lint
static char sccsid[] = "@(#)look.c      5.3 (Berkeley) 2/26/91";
#endif /* not lint */

/*
* look.c
* Facility: m4 macro processor
* by: oz
*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "mdef.h"
#include "extr.h"

/*
*  hash - compute hash value using the proverbial
*         hashing function. Taken from K&R.
*/
hash (name)
register char *name;
{
       register int h = 0;
       while (*name)
               h += *name++;
       return (h % HASHSIZE);
}

/*
* lookup - find name in the hash table
*
*/
ndptr lookup(name)
char *name;
{
       register ndptr p;

       for (p = hashtab[hash(name)]; p != nil; p = p->nxtptr)
               if (strcmp(name, p->name) == 0)
                       break;
       return (p);
}

/*
* addent - hash and create an entry in the hash
*          table. The new entry is added in front
*          of a hash bucket.
*/
ndptr addent(name)
char *name;
{
       register int h;
       ndptr p;

       h = hash(name);
       if ((p = (ndptr) malloc(sizeof(struct ndblock))) != NULL) {
               p->nxtptr = hashtab[h];
               hashtab[h] = p;
               p->name = strdup(name);
       }
       else
               error("m4: no more memory.");
       return p;
}

/*
* remhash - remove an entry from the hashtable
*
*/
remhash(name, all)
char *name;
int all;
{
       register int h;
       register ndptr xp, tp, mp;

       h = hash(name);
       mp = hashtab[h];
       tp = nil;
       while (mp != nil) {
               if (strcmp(mp->name, name) == 0) {
                       mp = mp->nxtptr;
                       if (tp == nil) {
                               freent(hashtab[h]);
                               hashtab[h] = mp;
                       }
                       else {
                               xp = tp->nxtptr;
                               tp->nxtptr = mp;
                               freent(xp);
                       }
                       if (!all)
                               break;
               }
               else {
                       tp = mp;
                       mp = mp->nxtptr;
               }
       }
}

/*
* freent - free a hashtable information block
*
*/
freent(p)
ndptr p;
{
       if (!(p->type & STATIC)) {
               free(p->name);
               if (p->defn != null)
                       free(p->defn);
       }
       free(p);
}