Add EVEN(): Micro-optimize "up to multiple of 2".

diff --git a/libraries/liblmdb/mdb.c b/libraries/liblmdb/mdb.c
index e0ab71a5ee207a5afb26081b5e1fbe65dd2f1dc1..a6da9a591a191799f75475e56d097bc89030003c 100644 (file)
--- a/libraries/liblmdb/mdb.c
+++ b/libraries/liblmdb/mdb.c
@@ -428,6 +428,9 @@ static txnid_t mdb_debug_start;
        /** Test if the flags \b f are set in a flag word \b w. */
 #define F_ISSET(w, f)   (((w) & (f)) == (f))
 
+       /** Round \b n up to an even number. */
+#define EVEN(n)                (((n) + 1U) & -2) /* sign-extending -2 to match n+1U */
+
        /**     Used for offsets within a single page.
         *      Since memory pages are typically 4 or 8KB in size, 12-13 bits,
         *      this is plenty.
@@ -1246,7 +1249,7 @@ mdb_page_list(MDB_page *mp)
                        nsize += sizeof(indx_t);
                        fprintf(stderr, "key %d: nsize %d, %s\n", i, nsize, DKEY(&key));
                }
-               total += (total & 1);
+               total = EVEN(total);
        }
        fprintf(stderr, "Total: %d\n", total);
 }
@@ -5870,8 +5873,8 @@ more:
                                switch (flags) {
                                default:
                                        if (!(mc->mc_db->md_flags & MDB_DUPFIXED)) {
-                                               offset = NODESIZE + sizeof(indx_t) + data->mv_size;
-                                               offset += offset & 1;
+                                               offset = EVEN(NODESIZE + sizeof(indx_t) +
+                                                       data->mv_size);
                                                break;
                                        }
                                        offset = fp->mp_pad;
@@ -6255,9 +6258,8 @@ mdb_leaf_size(MDB_env *env, MDB_val *key, MDB_val *data)
                /* put on overflow page */
                sz -= data->mv_size - sizeof(pgno_t);
        }
-       sz += sz & 1;
 
-       return sz + sizeof(indx_t);
+       return EVEN(sz + sizeof(indx_t));
 }
 
 /** Calculate the size of a branch node.
@@ -6351,7 +6353,7 @@ mdb_node_add(MDB_cursor *mc, indx_t indx,
                        /* Put data on overflow page. */
                        DPRINTF(("data size is %"Z"u, node would be %"Z"u, put data on overflow page",
                            data->mv_size, node_size+data->mv_size));
-                       node_size += sizeof(pgno_t) + (node_size & 1);
+                       node_size = EVEN(node_size + sizeof(pgno_t));
                        if ((ssize_t)node_size > room)
                                goto full;
                        if ((rc = mdb_page_new(mc, P_OVERFLOW, ovpages, &ofp)))
@@ -6363,7 +6365,7 @@ mdb_node_add(MDB_cursor *mc, indx_t indx,
                        node_size += data->mv_size;
                }
        }
-       node_size += node_size & 1;
+       node_size = EVEN(node_size);
        if ((ssize_t)node_size > room)
                goto full;
 
@@ -6464,7 +6466,7 @@ mdb_node_del(MDB_page *mp, indx_t indx, int ksize)
                else
                        sz += NODEDSZ(node);
        }
-       sz += sz & 1;
+       sz = EVEN(sz);
 
        ptr = mp->mp_ptrs[indx];
        numkeys = NUMKEYS(mp);
@@ -6779,15 +6781,12 @@ mdb_update_key(MDB_cursor *mc, MDB_val *key)
        }
 #endif
 
-       ksize = key->mv_size;
-       ksize += (ksize & 1);
-       oksize = node->mn_ksize;
-       oksize += (oksize & 1);
+       /* Sizes must be 2-byte aligned. */
+       ksize = EVEN(key->mv_size);
+       oksize = EVEN(node->mn_ksize);
        delta = ksize - oksize;
 
-       /* Must be 2-byte aligned. If new key is
-        * shorter by 1, the shift will be skipped.
-        */
+       /* Shift node contents if EVEN(key length) changed. */
        if (delta) {
                if (delta > 0 && SIZELEFT(mp) < delta) {
                        pgno_t pgno;
@@ -7565,7 +7564,7 @@ mdb_page_split(MDB_cursor *mc, MDB_val *newkey, MDB_val *newdata, pgno_t newpgno
                                nsize = mdb_leaf_size(env, newkey, newdata);
                        else
                                nsize = mdb_branch_size(env, newkey);
-                       nsize += nsize & 1;
+                       nsize = EVEN(nsize);
 
                        /* grab a page to hold a temporary copy */
                        copy = mdb_page_malloc(mc->mc_txn, 1);
@@ -7622,7 +7621,7 @@ mdb_page_split(MDB_cursor *mc, MDB_val *newkey, MDB_val *newdata, pgno_t newpgno
                                                        else
                                                                psize += NODEDSZ(node);
                                                }
-                                               psize += psize & 1;
+                                               psize = EVEN(psize);
                                        }
                                        if (psize > pmax || i == k-j) {
                                                split_indx = i + (j<0);