From 172d825155a7ba595527181277983ba4022c2115 Mon Sep 17 00:00:00 2001 From: Hallvard Furuseth Date: Sun, 12 Mar 2017 16:58:51 +0100 Subject: Simplify mdb_hash_val() -> mdb_hash() Simpler usage since it's only called once, rename to match new usage, and drop 3 loop pessimizations which were optimizations 20 years ago. --- libraries/liblmdb/mdb.c | 32 ++++++++------------------------ 1 file changed, 8 insertions(+), 24 deletions(-) (limited to 'libraries') diff --git a/libraries/liblmdb/mdb.c b/libraries/liblmdb/mdb.c index d28f42a..e2b4858 100644 --- a/libraries/liblmdb/mdb.c +++ b/libraries/liblmdb/mdb.c @@ -4965,31 +4965,21 @@ mdb_env_excl_lock(MDB_env *env, int *excl) * Share and Enjoy! :-) */ -#define MDB_HASH_INIT ((mdb_hash_t)0xcbf29ce484222325ULL) - /** perform a 64 bit Fowler/Noll/Vo FNV-1a hash on a buffer * @param[in] val value to hash - * @param[in] hval initial value for hash + * @param[in] len length of value * @return 64 bit hash - * - * NOTE: To use the recommended 64 bit FNV-1a hash, use MDB_HASH_INIT as the - * hval arg on the first call. */ static mdb_hash_t -mdb_hash_val(MDB_val *val, mdb_hash_t hval) +mdb_hash(const void *val, size_t len) { - unsigned char *s = (unsigned char *)val->mv_data; /* unsigned string */ - unsigned char *end = s + val->mv_size; + const unsigned char *s = (const unsigned char *) val, *end = s + len; + mdb_hash_t hval = 0xcbf29ce484222325ULL; /* - * FNV-1a hash each octet of the string + * FNV-1a hash each octet of the buffer */ while (s < end) { - /* xor the bottom with the current octet */ - hval ^= (mdb_hash_t)*s++; - - /* multiply by the 64 bit FNV magic prime mod 2^64 */ - hval += (hval << 1) + (hval << 4) + (hval << 5) + - (hval << 7) + (hval << 8) + (hval << 40); + hval = (hval ^ *s++) * 0x100000001b3ULL; } /* return our new hash value */ return hval; @@ -5130,7 +5120,6 @@ mdb_env_setup_locks(MDB_env *env, MDB_name *fname, int mode, int *excl) DWORD nhigh; DWORD nlow; } idbuf; - MDB_val val; if (!mdb_sec_inited) { InitializeSecurityDescriptor(&mdb_null_sd, @@ -5145,9 +5134,7 @@ mdb_env_setup_locks(MDB_env *env, MDB_name *fname, int mode, int *excl) idbuf.volume = stbuf.dwVolumeSerialNumber; idbuf.nhigh = stbuf.nFileIndexHigh; idbuf.nlow = stbuf.nFileIndexLow; - val.mv_data = &idbuf; - val.mv_size = sizeof(idbuf); - env->me_txns->mti_mutexid = mdb_hash_val(&val, MDB_HASH_INIT); + env->me_txns->mti_mutexid = mdb_hash(&idbuf, sizeof(idbuf)); mdb_env_mname_init(env); env->me_rmutex = CreateMutexA(&mdb_all_sa, FALSE, MUTEXNAME(env, 'r')); if (!env->me_rmutex) goto fail_errno; @@ -5159,7 +5146,6 @@ mdb_env_setup_locks(MDB_env *env, MDB_name *fname, int mode, int *excl) dev_t dev; ino_t ino; } idbuf; - MDB_val val; #if defined(__NetBSD__) #define MDB_SHORT_SEMNAMES 1 /* limited to 14 chars */ @@ -5167,9 +5153,7 @@ mdb_env_setup_locks(MDB_env *env, MDB_name *fname, int mode, int *excl) if (fstat(env->me_lfd, &stbuf)) goto fail_errno; idbuf.dev = stbuf.st_dev; idbuf.ino = stbuf.st_ino; - val.mv_data = &idbuf; - val.mv_size = sizeof(idbuf); - env->me_txns->mti_mutexid = mdb_hash_val(&val, MDB_HASH_INIT) + env->me_txns->mti_mutexid = mdb_hash(&idbuf, sizeof(idbuf)) #ifdef MDB_SHORT_SEMNAMES /* Max 9 base85-digits. We truncate here instead of in * mdb_env_mname_init() to keep the latter portable. -- cgit v1.2.3