1/* $OpenLDAP$ */ 2/* This work is part of OpenLDAP Software <http://www.openldap.org/>. 3 * 4 * Copyright 2000-2011 The OpenLDAP Foundation. 5 * Portions Copyright 2000-2003 Kurt D. Zeilenga. 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted only as authorized by the OpenLDAP 10 * Public License. 11 * 12 * A copy of this license is available in the file LICENSE in the 13 * top-level directory of the distribution or, alternatively, at 14 * <http://www.OpenLDAP.org/license.html>. 15 */ 16 17/* This implements the Fowler / Noll / Vo (FNV-1) hash algorithm. 18 * A summary of the algorithm can be found at: 19 * http://www.isthe.com/chongo/tech/comp/fnv/index.html 20 */ 21 22#include "portable.h" 23 24#include <lutil_hash.h> 25 26/* offset and prime for 32-bit FNV-1 */ 27#define HASH_OFFSET 0x811c9dc5U 28#define HASH_PRIME 16777619 29 30 31/* 32 * Initialize context 33 */ 34void 35lutil_HASHInit( struct lutil_HASHContext *ctx ) 36{ 37 ctx->hash = HASH_OFFSET; 38} 39 40/* 41 * Update hash 42 */ 43void 44lutil_HASHUpdate( 45 struct lutil_HASHContext *ctx, 46 const unsigned char *buf, 47 ber_len_t len ) 48{ 49 const unsigned char *p, *e; 50 ber_uint_t h; 51 52 p = buf; 53 e = &buf[len]; 54 55 h = ctx->hash; 56 57 while( p < e ) { 58 h *= HASH_PRIME; 59 h ^= *p++; 60 } 61 62 ctx->hash = h; 63} 64 65/* 66 * Save hash 67 */ 68void 69lutil_HASHFinal( unsigned char *digest, struct lutil_HASHContext *ctx ) 70{ 71 ber_uint_t h = ctx->hash; 72 73 digest[0] = h & 0xffU; 74 digest[1] = (h>>8) & 0xffU; 75 digest[2] = (h>>16) & 0xffU; 76 digest[3] = (h>>24) & 0xffU; 77} 78