cwchash/hashtable_utility.c

   1 /* Copyright (C) 2002 Christopher Clark <firstname.lastname@cl.cam.ac.uk> */
   2
   3 #include "hashtable.h"
   4 #include "hashtable_private.h"
   5 #include "hashtable_utility.h"
   6 #include <stdlib.h>
   7 #include <stdio.h>
   8 #include <string.h>
   9
  10 /*****************************************************************************/
  11 /* hashtable_change
  12  *
  13  * function to change the value associated with a key, where there already
  14  * exists a value bound to the key in the hashtable.
  15  * Source due to Holger Schemel.
  16  *
  17  *  */
  18 int
  19 hashtable_change(struct hashtable *h, void *k, void *v)
  20 {
  21     struct entry *e;
  22     unsigned int hashvalue, index;
  23     hashvalue = hash(h,k);
  24     index = indexFor(h->tablelength,hashvalue);
  25     e = h->table[index];
  26     while (NULL != e)
  27     {
  28         /* Check hash value to short circuit heavier comparison */
  29         if ((hashvalue == e->h) && (h->eqfn(k, e->k)))
  30         {
  31             free(e->v);
  32             e->v = v;
  33             return -1;
  34         }
  35         e = e->next;
  36     }
  37     return 0;
  38 }
  39
  40 /*
  41  * Copyright (c) 2002, Christopher Clark
  42  * All rights reserved.
  43  *
  44  * Redistribution and use in source and binary forms, with or without
  45  * modification, are permitted provided that the following conditions
  46  * are met:
  47  *
  48  * * Redistributions of source code must retain the above copyright
  49  * notice, this list of conditions and the following disclaimer.
  50  *
  51  * * Redistributions in binary form must reproduce the above copyright
  52  * notice, this list of conditions and the following disclaimer in the
  53  * documentation and/or other materials provided with the distribution.
  54  *
  55  * * Neither the name of the original author; nor the names of any contributors
  56  * may be used to endorse or promote products derived from this software
  57  * without specific prior written permission.
  58  *
  59  *
  60  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  61  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  62  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  63  * A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER
  64  * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  65  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  66  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  67  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  68  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  69  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  70  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  71 */