usr.bin/m4/look.c

   1 /*
   2  * Copyright (c) 1989, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * This code is derived from software contributed to Berkeley by
   6  * Ozan Yigit at York University.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. All advertising materials mentioning features or use of this software
  17  *    must display the following acknowledgement:
  18  *      This product includes software developed by the University of
  19  *      California, Berkeley and its contributors.
  20  * 4. Neither the name of the University nor the names of its contributors
  21  *    may be used to endorse or promote products derived from this software
  22  *    without specific prior written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  34  * SUCH DAMAGE.
  35  *
  36  * @(#)look.c   8.1 (Berkeley) 6/6/93
  37  * $OpenBSD: look.c,v 1.10 2002/04/26 16:15:16 espie Exp $
  38  * $FreeBSD: src/usr.bin/m4/look.c,v 1.7 2002/07/15 02:15:12 jmallett Exp $
  39  * $DragonFly: src/usr.bin/m4/look.c,v 1.3 2006/12/27 21:29:02 pavalos Exp $
  40  */
  41
  42 /*
  43  * look.c
  44  * Facility: m4 macro processor
  45  * by: oz
  46  */
  47
  48 #include <sys/types.h>
  49 #include <stdio.h>
  50 #include <stdlib.h>
  51 #include <stddef.h>
  52 #include <string.h>
  53 #include "mdef.h"
  54 #include "stdd.h"
  55 #include "extern.h"
  56
  57 static void freent(ndptr);
  58
  59 unsigned int
  60 hash(const char *name)
  61 {
  62         unsigned int h = 0;
  63         while (*name)
  64                 h = (h << 5) + h + *name++;
  65         return (h);
  66 }
  67
  68 /*
  69  * find name in the hash table
  70  */
  71 ndptr
  72 lookup(const char *name)
  73 {
  74         ndptr p;
  75         unsigned int h;
  76
  77         h = hash(name);
  78         for (p = hashtab[h % HASHSIZE]; p != nil; p = p->nxtptr)
  79                 if (h == p->hv && STREQ(name, p->name))
  80                         break;
  81         return (p);
  82 }
  83
  84 /*
  85  * hash and create an entry in the hash table.
  86  * The new entry is added in front of a hash bucket.
  87  */
  88 ndptr
  89 addent(const char *name)
  90 {
  91         unsigned int h;
  92         ndptr p;
  93
  94         h = hash(name);
  95         p = (ndptr) xalloc(sizeof(struct ndblock));
  96         p->nxtptr = hashtab[h % HASHSIZE];
  97         hashtab[h % HASHSIZE] = p;
  98         p->name = xstrdup(name);
  99         p->hv = h;
 100         return p;
 101 }
 102
 103 static void
 104 freent(ndptr p)
 105 {
 106         free((char *) p->name);
 107         if (p->defn != null)
 108                 free((char *) p->defn);
 109         free((char *) p);
 110 }
 111
 112 /*
 113  * remove an entry from the hashtable
 114  */
 115 void
 116 remhash(const char *name, int all)
 117 {
 118         unsigned int h;
 119         ndptr xp, tp, mp;
 120
 121         h = hash(name);
 122         mp = hashtab[h % HASHSIZE];
 123         tp = nil;
 124         while (mp != nil) {
 125                 if (mp->hv == h && STREQ(mp->name, name)) {
 126                         mp = mp->nxtptr;
 127                         if (tp == nil) {
 128                                 freent(hashtab[h % HASHSIZE]);
 129                                 hashtab[h % HASHSIZE] = mp;
 130                         }
 131                         else {
 132                                 xp = tp->nxtptr;
 133                                 tp->nxtptr = mp;
 134                                 freent(xp);
 135                         }
 136                         if (!all)
 137                                 break;
 138                 }
 139                 else {
 140                         tp = mp;
 141                         mp = mp->nxtptr;
 142                 }
 143         }
 144 }