cctools/libstuff/hash_string.c

   1 /*
   2  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23 #include <stdint.h>
  24 #include "stuff/hash_string.h"
  25 /*
  26  * A hash function used for converting a string into a single number.  It is
  27  * then usually mod'ed with the hash table size to get an index into the hash
  28  * table.
  29  */
  30 __private_extern__
  31 int32_t
  32 hash_string(
  33 char *key)
  34 {
  35     char *cp;
  36     int32_t k;
  37
  38         cp = key;
  39         k = 0;
  40         while(*cp)
  41             k = (((k << 1) + (k >> 14)) ^ (*cp++)) & 0x3fff;
  42         return(k);
  43 }