Precalculate max size of a node

libraries/liblmdb/mdb.c

@@ -957,6 +957,8 @@ struct MDB_env {
 	MDB_ID2		me_dirty_list[MDB_IDL_UM_SIZE];
 	/** Max number of freelist items that can fit in a single overflow page */
 	unsigned int	me_maxfree_1pg;
+	/** Max size of a node on a page */
+	unsigned int	me_nodemax;
 #ifdef _WIN32
 	HANDLE		me_rmutex;		/* Windows mutexes don't reside in shared mem */
 	HANDLE		me_wmutex;
@@ -2897,6 +2899,7 @@ mdb_env_open2(MDB_env *env)
 	}
 	env->me_psize = meta.mm_psize;
 	env->me_maxfree_1pg = (env->me_psize - PAGEHDRSZ) / sizeof(pgno_t) - 1;
+	env->me_nodemax = (env->me_psize - PAGEHDRSZ) / MDB_MINKEYS;
 
 	env->me_maxpg = env->me_mapsize / env->me_psize;
 
@@ -5037,8 +5040,7 @@ reuse:
 				}
 				offset += offset & 1;
 				if (NODESIZE + sizeof(indx_t) + NODEKSZ(leaf) + NODEDSZ(leaf) +
-					offset >= (mc->mc_txn->mt_env->me_psize - PAGEHDRSZ) /
-						MDB_MINKEYS) {
+					offset >= mc->mc_txn->mt_env->me_nodemax) {
 					/* yes, convert it */
 					dummy.md_flags = 0;
 					if (mc->mc_db->md_flags & MDB_DUPFIXED) {
@@ -5353,7 +5355,7 @@ mdb_leaf_size(MDB_env *env, MDB_val *key, MDB_val *data)
 	size_t		 sz;
 
 	sz = LEAFSIZE(key, data);
-	if (sz >= env->me_psize / MDB_MINKEYS) {
+	if (sz >= env->me_nodemax) {
 		/* put on overflow page */
 		sz -= data->mv_size - sizeof(pgno_t);
 	}
@@ -5378,7 +5380,7 @@ mdb_branch_size(MDB_env *env, MDB_val *key)
 	size_t		 sz;
 
 	sz = INDXSIZE(key);
-	if (sz >= env->me_psize / MDB_MINKEYS) {
+	if (sz >= env->me_nodemax) {
 		/* put on overflow page */
 		/* not implemented */
 		/* sz -= key->size - sizeof(pgno_t); */
@@ -5446,7 +5448,7 @@ mdb_node_add(MDB_cursor *mc, indx_t indx,
 		if (F_ISSET(flags, F_BIGDATA)) {
 			/* Data already on overflow page. */
 			node_size += sizeof(pgno_t);
-		} else if (node_size + data->mv_size >= mc->mc_txn->mt_env->me_psize / MDB_MINKEYS) {
+		} else if (node_size + data->mv_size >= mc->mc_txn->mt_env->me_nodemax) {
 			int ovpages = OVPAGES(data->mv_size, mc->mc_txn->mt_env->me_psize);
 			int rc;
 			/* Put data on overflow page. */