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-rw-r--r--libraries/liblutil/hash.c141
1 files changed, 141 insertions, 0 deletions
diff --git a/libraries/liblutil/hash.c b/libraries/liblutil/hash.c
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+/* $OpenLDAP$ */
+/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
+ *
+ * Copyright 2000-2022 The OpenLDAP Foundation.
+ * Portions Copyright 2000-2003 Kurt D. Zeilenga.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted only as authorized by the OpenLDAP
+ * Public License.
+ *
+ * A copy of this license is available in the file LICENSE in the
+ * top-level directory of the distribution or, alternatively, at
+ * <http://www.OpenLDAP.org/license.html>.
+ */
+
+/* This implements the Fowler / Noll / Vo (FNV-1) hash algorithm.
+ * A summary of the algorithm can be found at:
+ * http://www.isthe.com/chongo/tech/comp/fnv/index.html
+ */
+
+#include "portable.h"
+
+#include <lutil_hash.h>
+
+/* offset and prime for 32-bit FNV-1 */
+#define HASH_OFFSET 0x811c9dc5U
+#define HASH_PRIME 16777619
+
+
+/*
+ * Initialize context
+ */
+void
+lutil_HASHInit( lutil_HASH_CTX *ctx )
+{
+ ctx->hash = HASH_OFFSET;
+}
+
+/*
+ * Update hash
+ */
+void
+lutil_HASHUpdate(
+ lutil_HASH_CTX *ctx,
+ const unsigned char *buf,
+ ber_len_t len )
+{
+ const unsigned char *p, *e;
+ ber_uint_t h;
+
+ p = buf;
+ e = &buf[len];
+
+ h = ctx->hash;
+
+ while( p < e ) {
+ h *= HASH_PRIME;
+ h ^= *p++;
+ }
+
+ ctx->hash = h;
+}
+
+/*
+ * Save hash
+ */
+void
+lutil_HASHFinal( unsigned char *digest, lutil_HASH_CTX *ctx )
+{
+ ber_uint_t h = ctx->hash;
+
+ digest[0] = h & 0xffU;
+ digest[1] = (h>>8) & 0xffU;
+ digest[2] = (h>>16) & 0xffU;
+ digest[3] = (h>>24) & 0xffU;
+}
+
+#ifdef HAVE_LONG_LONG
+
+/* 64 bit Fowler/Noll/Vo-O FNV-1a hash code */
+
+#define HASH64_OFFSET 0xcbf29ce484222325ULL
+
+/*
+ * Initialize context
+ */
+void
+lutil_HASH64Init( lutil_HASH_CTX *ctx )
+{
+ ctx->hash64 = HASH64_OFFSET;
+}
+
+/*
+ * Update hash
+ */
+void
+lutil_HASH64Update(
+ lutil_HASH_CTX *ctx,
+ const unsigned char *buf,
+ ber_len_t len )
+{
+ const unsigned char *p, *e;
+ unsigned long long h;
+
+ p = buf;
+ e = &buf[len];
+
+ h = ctx->hash64;
+
+ while( p < e ) {
+ /* xor the bottom with the current octet */
+ h ^= *p++;
+
+ /* multiply by the 64 bit FNV magic prime mod 2^64 */
+ h += (h << 1) + (h << 4) + (h << 5) +
+ (h << 7) + (h << 8) + (h << 40);
+
+ }
+
+ ctx->hash64 = h;
+}
+
+/*
+ * Save hash
+ */
+void
+lutil_HASH64Final( unsigned char *digest, lutil_HASH_CTX *ctx )
+{
+ unsigned long long h = ctx->hash64;
+
+ digest[0] = h & 0xffU;
+ digest[1] = (h>>8) & 0xffU;
+ digest[2] = (h>>16) & 0xffU;
+ digest[3] = (h>>24) & 0xffU;
+ digest[4] = (h>>32) & 0xffU;
+ digest[5] = (h>>40) & 0xffU;
+ digest[6] = (h>>48) & 0xffU;
+ digest[7] = (h>>56) & 0xffU;
+}
+#endif /* HAVE_LONG_LONG */