usr.bin/xlint/lint2/hash.c

   1 /*      $NetBSD: hash.c,v 1.2 1995/07/03 21:24:47 cgd Exp $     */
   2
   3 /*
   4  * Copyright (c) 1994, 1995 Jochen Pohl
   5  * All Rights Reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. All advertising materials mentioning features or use of this software
  16  *    must display the following acknowledgement:
  17  *      This product includes software developed by Jochen Pohl for
  18  *      The NetBSD Project.
  19  * 4. The name of the author may not be used to endorse or promote products
  20  *    derived from this software without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  23  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  24  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  25  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  26  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  27  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  28  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  29  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  30  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  31  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  32  *
  33  * $NetBSD: hash.c,v 1.2 1995/07/03 21:24:47 cgd Exp $
  34  * $DragonFly: src/usr.bin/xlint/lint2/hash.c,v 1.5 2004/07/07 12:13:26 asmodai Exp $
  35  */
  36
  37 #include <stddef.h>
  38 #include <string.h>
  39 #include <limits.h>
  40
  41 #include "lint2.h"
  42
  43 /* pointer to hash table, initialized in inithash() */
  44 static  hte_t   **htab;
  45
  46 static  int     hash(const char *);
  47
  48 /*
  49  * Initialize hash table.
  50  */
  51 void
  52 inithash(void)
  53 {
  54         htab = xcalloc(HSHSIZ2, sizeof (hte_t *));
  55 }
  56
  57 /*
  58  * Compute hash value from a string.
  59  */
  60 static int
  61 hash(const char *s)
  62 {
  63         u_int   v;
  64         const   u_char *us;
  65
  66         v = 0;
  67         for (us = (const u_char *)s; *us != '\0'; us++) {
  68                 v = (v << sizeof (v)) + *us;
  69                 v ^= v >> (sizeof (v) * CHAR_BIT - sizeof (v));
  70         }
  71         return (v % HSHSIZ2);
  72 }
  73
  74 /*
  75  * Look for a hash table entry. If no hash table entry for the
  76  * given name exists and mknew is set, create a new one.
  77  */
  78 hte_t *
  79 hsearch(const char *s, int mknew)
  80 {
  81         int     h;
  82         hte_t   *hte;
  83
  84         h = hash(s);
  85         for (hte = htab[h]; hte != NULL; hte = hte->h_link) {
  86                 if (strcmp(hte->h_name, s) == 0)
  87                         break;
  88         }
  89
  90         if (hte != NULL || !mknew)
  91                 return (hte);
  92
  93         /* create a new hte */
  94         hte = xalloc(sizeof (hte_t));
  95         hte->h_name = xstrdup(s);
  96         hte->h_lsym = &hte->h_syms;
  97         hte->h_lcall = &hte->h_calls;
  98         hte->h_lusym = &hte->h_usyms;
  99         hte->h_link = htab[h];
 100         htab[h] = hte;
 101
 102         return (hte);
 103 }
 104
 105 /*
 106  * Call function f for each name in the hash table.
 107  */
 108 void
 109 forall(void (*f)(hte_t *))
 110 {
 111         int     i;
 112         hte_t   *hte;
 113
 114         for (i = 0; i < HSHSIZ2; i++) {
 115                 for (hte = htab[i]; hte != NULL; hte = hte->h_link)
 116                         (*f)(hte);
 117         }
 118 }