src/system/kernel/util/StringHash.cpp

   1 /*
   2  * Copyright 2002-2013, Haiku, Inc. All rights reserved.
   3  * Distributed under the terms of the MIT License.
   4  *
   5  * Copyright 2001, Travis Geiselbrecht. All rights reserved.
   6  * Distributed under the terms of the NewOS License.
   7  */
   8
   9
  10 #include <util/StringHash.h>
  11
  12
  13 uint32
  14 hash_hash_string(const char* string)
  15 {
  16         uint32 hash = 0;
  17         char c;
  18
  19         // we assume hash to be at least 32 bits
  20         while ((c = *string++) != 0) {
  21                 hash ^= hash >> 28;
  22                 hash <<= 4;
  23                 hash ^= c;
  24         }
  25
  26         return hash;
  27 }
  28
  29
  30 uint32
  31 hash_hash_string_part(const char* string, size_t maxLength)
  32 {
  33         uint32 hash = 0;
  34         char c;
  35
  36         // we assume hash to be at least 32 bits
  37         while (maxLength-- > 0 && (c = *string++) != 0) {
  38                 hash ^= hash >> 28;
  39                 hash <<= 4;
  40                 hash ^= c;
  41         }
  42
  43         return hash;
  44 }