hashkey.c

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/* hashkey.c -- definition of hash key type and helper functions
 *
 * Copyright (C) 2010,2011 Olaf Bergmann <bergmann@tzi.org>
 *
 * This file is part of the CoAP library libcoap. Please see
 * README for terms of use. 
 */

#include "hashkey.h"

/* Caution: When changing this, update COAP_DEFAULT_WKC_HASHKEY
 * accordingly (see int coap_hash_path());
 */
void
coap_hash_impl(const unsigned char *s, unsigned int len, coap_key_t h) {
  size_t j;

  while (len--) {
    j = sizeof(coap_key_t)-1;
  
    while (j) {
      h[j] = ((h[j] << 7) | (h[j-1] >> 1)) + h[j];
      --j;
    }

    h[0] = (h[0] << 7) + h[0] + *s++;
  }
}