1 /* $OpenBSD: look.c,v 1.7 1999/11/25 00:54:22 millert Exp $ */ 2 3 /* 4 * Copyright (c) 1989, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Ozan Yigit at York University. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 */ 38 39 #ifndef lint 40 static char sccsid[] = "@(#)look.c 8.1 (Berkeley) 6/6/93"; 41 #endif /* not lint */ 42 43 /* 44 * look.c 45 * Facility: m4 macro processor 46 * by: oz 47 */ 48 49 #include <sys/types.h> 50 #include <stdio.h> 51 #include <stdlib.h> 52 #include <stddef.h> 53 #include <string.h> 54 #include "mdef.h" 55 #include "stdd.h" 56 #include "extern.h" 57 58 static void freent __P((ndptr)); 59 60 unsigned 61 hash(name) 62 const char *name; 63 { 64 unsigned int h = 0; 65 while (*name) 66 h = (h << 5) + h + *name++; 67 return (h); 68 } 69 70 /* 71 * find name in the hash table 72 */ 73 ndptr 74 lookup(name) 75 const char *name; 76 { 77 ndptr p; 78 unsigned int h; 79 80 h = hash(name); 81 for (p = hashtab[h % HASHSIZE]; p != nil; p = p->nxtptr) 82 if (h == p->hv && STREQ(name, p->name)) 83 break; 84 return (p); 85 } 86 87 /* 88 * hash and create an entry in the hash table. 89 * The new entry is added in front of a hash bucket. 90 */ 91 ndptr 92 addent(name) 93 const char *name; 94 { 95 unsigned int h; 96 ndptr p; 97 98 h = hash(name); 99 p = (ndptr) xalloc(sizeof(struct ndblock)); 100 p->nxtptr = hashtab[h % HASHSIZE]; 101 hashtab[h % HASHSIZE] = p; 102 p->name = xstrdup(name); 103 p->hv = h; 104 return p; 105 } 106 107 static void 108 freent(p) 109 ndptr p; 110 { 111 if (!(p->type & STATIC)) { 112 free((char *) p->name); 113 if (p->defn != null) 114 free((char *) p->defn); 115 } 116 free((char *) p); 117 } 118 119 /* 120 * remove an entry from the hashtable 121 */ 122 void 123 remhash(name, all) 124 const char *name; 125 int all; 126 { 127 unsigned int h; 128 ndptr xp, tp, mp; 129 130 h = hash(name); 131 mp = hashtab[h % HASHSIZE]; 132 tp = nil; 133 while (mp != nil) { 134 if (mp->hv == h && STREQ(mp->name, name)) { 135 mp = mp->nxtptr; 136 if (tp == nil) { 137 freent(hashtab[h % HASHSIZE]); 138 hashtab[h % HASHSIZE] = mp; 139 } 140 else { 141 xp = tp->nxtptr; 142 tp->nxtptr = mp; 143 freent(xp); 144 } 145 if (!all) 146 break; 147 } 148 else { 149 tp = mp; 150 mp = mp->nxtptr; 151 } 152 } 153 } 154