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      1 /*	$NetBSD: hash.c,v 1.4 2025/09/05 21:16:23 christos Exp $	*/
      2 
      3 /* $OpenLDAP$ */
      4 /* This work is part of OpenLDAP Software <http://www.openldap.org/>.
      5  *
      6  * Copyright 2000-2024 The OpenLDAP Foundation.
      7  * Portions Copyright 2000-2003 Kurt D. Zeilenga.
      8  * All rights reserved.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted only as authorized by the OpenLDAP
     12  * Public License.
     13  *
     14  * A copy of this license is available in the file LICENSE in the
     15  * top-level directory of the distribution or, alternatively, at
     16  * <http://www.OpenLDAP.org/license.html>.
     17  */
     18 
     19 /* This implements the Fowler / Noll / Vo (FNV-1) hash algorithm.
     20  * A summary of the algorithm can be found at:
     21  *   http://www.isthe.com/chongo/tech/comp/fnv/index.html
     22  */
     23 
     24 #include <sys/cdefs.h>
     25 __RCSID("$NetBSD: hash.c,v 1.4 2025/09/05 21:16:23 christos Exp $");
     26 
     27 #include "portable.h"
     28 
     29 #include <lutil_hash.h>
     30 
     31 /* offset and prime for 32-bit FNV-1 */
     32 #define HASH_OFFSET	0x811c9dc5U
     33 #define HASH_PRIME	16777619
     34 
     35 
     36 /*
     37  * Initialize context
     38  */
     39 void
     40 lutil_HASHInit( lutil_HASH_CTX *ctx )
     41 {
     42 	ctx->hash = HASH_OFFSET;
     43 }
     44 
     45 /*
     46  * Update hash
     47  */
     48 void
     49 lutil_HASHUpdate(
     50     lutil_HASH_CTX	*ctx,
     51     const unsigned char		*buf,
     52     ber_len_t		len )
     53 {
     54 	const unsigned char *p, *e;
     55 	ber_uint_t h;
     56 
     57 	p = buf;
     58 	e = &buf[len];
     59 
     60 	h = ctx->hash;
     61 
     62 	while( p < e ) {
     63 		h *= HASH_PRIME;
     64 		h ^= *p++;
     65 	}
     66 
     67 	ctx->hash = h;
     68 }
     69 
     70 /*
     71  * Save hash
     72  */
     73 void
     74 lutil_HASHFinal( unsigned char *digest, lutil_HASH_CTX *ctx )
     75 {
     76 	ber_uint_t h = ctx->hash;
     77 
     78 	digest[0] = h & 0xffU;
     79 	digest[1] = (h>>8) & 0xffU;
     80 	digest[2] = (h>>16) & 0xffU;
     81 	digest[3] = (h>>24) & 0xffU;
     82 }
     83 
     84 #ifdef HAVE_LONG_LONG
     85 
     86 /* 64 bit Fowler/Noll/Vo-O FNV-1a hash code */
     87 
     88 #define HASH64_OFFSET	0xcbf29ce484222325ULL
     89 
     90 /*
     91  * Initialize context
     92  */
     93 void
     94 lutil_HASH64Init( lutil_HASH_CTX *ctx )
     95 {
     96 	ctx->hash64 = HASH64_OFFSET;
     97 }
     98 
     99 /*
    100  * Update hash
    101  */
    102 void
    103 lutil_HASH64Update(
    104     lutil_HASH_CTX	*ctx,
    105     const unsigned char		*buf,
    106     ber_len_t		len )
    107 {
    108 	const unsigned char *p, *e;
    109 	unsigned long long h;
    110 
    111 	p = buf;
    112 	e = &buf[len];
    113 
    114 	h = ctx->hash64;
    115 
    116 	while( p < e ) {
    117 		/* xor the bottom with the current octet */
    118 		h ^= *p++;
    119 
    120 		/* multiply by the 64 bit FNV magic prime mod 2^64 */
    121 		h += (h << 1) + (h << 4) + (h << 5) +
    122 			(h << 7) + (h << 8) + (h << 40);
    123 
    124 	}
    125 
    126 	ctx->hash64 = h;
    127 }
    128 
    129 /*
    130  * Save hash
    131  */
    132 void
    133 lutil_HASH64Final( unsigned char *digest, lutil_HASH_CTX *ctx )
    134 {
    135 	unsigned long long h = ctx->hash64;
    136 
    137 	digest[0] = h & 0xffU;
    138 	digest[1] = (h>>8) & 0xffU;
    139 	digest[2] = (h>>16) & 0xffU;
    140 	digest[3] = (h>>24) & 0xffU;
    141 	digest[4] = (h>>32) & 0xffU;
    142 	digest[5] = (h>>40) & 0xffU;
    143 	digest[6] = (h>>48) & 0xffU;
    144 	digest[7] = (h>>56) & 0xffU;
    145 }
    146 #endif /* HAVE_LONG_LONG */
    147