crypto/heimdal-0.6.3/lib/asn1/hash.c

   1 /*
   2  * Copyright (c) 1997 Kungliga Tekniska Högskolan
   3  * (Royal Institute of Technology, Stockholm, Sweden).
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  *
  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  *
  17  * 3. Neither the name of the Institute nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 /*
  35  * Hash table functions
  36  */
  37
  38 #include "gen_locl.h"
  39
  40 RCSID("$Id: hash.c,v 1.8 1999/12/02 17:05:02 joda Exp $");
  41
  42 static Hashentry *_search(Hashtab * htab,       /* The hash table */
  43                           void *ptr);   /* And key */
  44
  45 Hashtab *
  46 hashtabnew(int sz,
  47            int (*cmp) (void *, void *),
  48            unsigned (*hash) (void *))
  49 {
  50     Hashtab *htab;
  51     int i;
  52
  53     assert(sz > 0);
  54
  55     htab = (Hashtab *) malloc(sizeof(Hashtab) + (sz - 1) * sizeof(Hashentry *));
  56     for (i = 0; i < sz; ++i)
  57         htab->tab[i] = NULL;
  58
  59     if (htab == NULL) {
  60         return NULL;
  61     } else {
  62         htab->cmp = cmp;
  63         htab->hash = hash;
  64         htab->sz = sz;
  65         return htab;
  66     }
  67 }
  68
  69 /* Intern search function */
  70
  71 static Hashentry *
  72 _search(Hashtab * htab, void *ptr)
  73 {
  74     Hashentry *hptr;
  75
  76     assert(htab && ptr);
  77
  78     for (hptr = htab->tab[(*htab->hash) (ptr) % htab->sz];
  79          hptr;
  80          hptr = hptr->next)
  81         if ((*htab->cmp) (ptr, hptr->ptr) == 0)
  82             break;
  83     return hptr;
  84 }
  85
  86 /* Search for element in hash table */
  87
  88 void *
  89 hashtabsearch(Hashtab * htab, void *ptr)
  90 {
  91     Hashentry *tmp;
  92
  93     tmp = _search(htab, ptr);
  94     return tmp ? tmp->ptr : tmp;
  95 }
  96
  97 /* add element to hash table */
  98 /* if already there, set new value */
  99 /* !NULL if succesful */
 100
 101 void *
 102 hashtabadd(Hashtab * htab, void *ptr)
 103 {
 104     Hashentry *h = _search(htab, ptr);
 105     Hashentry **tabptr;
 106
 107     assert(htab && ptr);
 108
 109     if (h)
 110         free((void *) h->ptr);
 111     else {
 112         h = (Hashentry *) malloc(sizeof(Hashentry));
 113         if (h == NULL) {
 114             return NULL;
 115         }
 116         tabptr = &htab->tab[(*htab->hash) (ptr) % htab->sz];
 117         h->next = *tabptr;
 118         *tabptr = h;
 119         h->prev = tabptr;
 120         if (h->next)
 121             h->next->prev = &h->next;
 122     }
 123     h->ptr = ptr;
 124     return h;
 125 }
 126
 127 /* delete element with key key. Iff freep, free Hashentry->ptr */
 128
 129 int
 130 _hashtabdel(Hashtab * htab, void *ptr, int freep)
 131 {
 132     Hashentry *h;
 133
 134     assert(htab && ptr);
 135
 136     h = _search(htab, ptr);
 137     if (h) {
 138         if (freep)
 139             free(h->ptr);
 140         if ((*(h->prev) = h->next))
 141             h->next->prev = h->prev;
 142         free(h);
 143         return 0;
 144     } else
 145         return -1;
 146 }
 147
 148 /* Do something for each element */
 149
 150 void
 151 hashtabforeach(Hashtab * htab, int (*func) (void *ptr, void *arg),
 152                void *arg)
 153 {
 154     Hashentry **h, *g;
 155
 156     assert(htab);
 157
 158     for (h = htab->tab; h < &htab->tab[htab->sz]; ++h)
 159         for (g = *h; g; g = g->next)
 160             if ((*func) (g->ptr, arg))
 161                 return;
 162 }
 163
 164 /* standard hash-functions for strings */
 165
 166 unsigned
 167 hashadd(const char *s)
 168 {                               /* Standard hash function */
 169     unsigned i;
 170
 171     assert(s);
 172
 173     for (i = 0; *s; ++s)
 174         i += *s;
 175     return i;
 176 }
 177
 178 unsigned
 179 hashcaseadd(const char *s)
 180 {                               /* Standard hash function */
 181     unsigned i;
 182
 183     assert(s);
 184
 185     for (i = 0; *s; ++s)
 186         i += toupper(*s);
 187     return i;
 188 }
 189
 190 #define TWELVE (sizeof(unsigned))
 191 #define SEVENTYFIVE (6*sizeof(unsigned))
 192 #define HIGH_BITS (~((unsigned)(~0) >> TWELVE))
 193
 194 unsigned
 195 hashjpw(const char *ss)
 196 {                               /* another hash function */
 197     unsigned h = 0;
 198     unsigned g;
 199     const unsigned char *s = (const unsigned char *)ss;
 200
 201     for (; *s; ++s) {
 202         h = (h << TWELVE) + *s;
 203         if ((g = h & HIGH_BITS))
 204             h = (h ^ (g >> SEVENTYFIVE)) & ~HIGH_BITS;
 205     }
 206     return h;
 207 }