cursor_set/search_node tweaks, use intcmp when possible
authorHoward Chu <highlandsun@gmail.com>
Tue, 13 Sep 2011 18:25:17 +0000 (11:25 -0700)
committerHoward Chu <highlandsun@gmail.com>
Tue, 13 Sep 2011 20:41:40 +0000 (13:41 -0700)
libraries/libmdb/mdb.c

index 94a650d..498d878 100644 (file)
@@ -850,7 +850,7 @@ static size_t       mdb_branch_size(MDB_env *env, MDB_val *key);
 static void mdb_default_cmp(MDB_txn *txn, MDB_dbi dbi);
 
 /** @cond */
-static MDB_cmp_func    memncmp, memnrcmp, intcmp, cintcmp;
+static MDB_cmp_func    memncmp, memnrcmp, intcmp, cintcmp, longcmp;
 /** @endcond */
 
 #ifdef _WIN32
@@ -2291,22 +2291,20 @@ mdb_env_close(MDB_env *env)
        free(env);
 }
 
+/* only for aligned size_t's */
+static int
+longcmp(const MDB_val *a, const MDB_val *b)
+{
+       return (*(size_t *)a->mv_data < *(size_t *)b->mv_data) ? -1 :
+               *(size_t *)a->mv_data > *(size_t *)b->mv_data;
+}
+
 /* only for aligned ints */
 static int
 intcmp(const MDB_val *a, const MDB_val *b)
 {
-       if (a->mv_size == sizeof(long))
-       {
-               unsigned long *la, *lb;
-               la = a->mv_data;
-               lb = b->mv_data;
-               return *la - *lb;
-       } else {
-               unsigned int *ia, *ib;
-               ia = a->mv_data;
-               ib = b->mv_data;
-               return *ia - *ib;
-       }
+       return (*(unsigned int *)a->mv_data < *(unsigned int *)b->mv_data) ? -1 :
+               *(unsigned int *)a->mv_data > *(unsigned int *)b->mv_data;
 }
 
 /* ints must always be the same size */
@@ -2401,6 +2399,17 @@ mdb_search_node(MDB_cursor *mc, MDB_val *key, int *exactp)
        low = IS_LEAF(mp) ? 0 : 1;
        high = nkeys - 1;
        cmp = mc->mc_dbx->md_cmp;
+
+       /* Branch pages have no data, so if using integer keys,
+        * alignment is guaranteed. Use faster intcmp.
+        */
+       if (cmp == cintcmp && IS_BRANCH(mp)) {
+               if (NODEPTR(mp, 1)->mn_ksize == sizeof(size_t))
+                       cmp = longcmp;
+               else
+                       cmp = intcmp;
+       }
+
        if (IS_LEAF2(mp)) {
                nodekey.mv_size = mc->mc_db->md_pad;
                node = NODEPTR(mp, 0);  /* fake */
@@ -2867,6 +2876,7 @@ mdb_cursor_set(MDB_cursor *mc, MDB_val *key, MDB_val *data,
     MDB_cursor_op op, int *exactp)
 {
        int              rc;
+       MDB_page        *mp;
        MDB_node        *leaf;
        DKBUF;
 
@@ -2878,11 +2888,12 @@ mdb_cursor_set(MDB_cursor *mc, MDB_val *key, MDB_val *data,
        if (mc->mc_flags & C_INITIALIZED) {
                MDB_val nodekey;
 
-               if (mc->mc_pg[mc->mc_top]->mp_flags & P_LEAF2) {
+               mp = mc->mc_pg[mc->mc_top];
+               if (mp->mp_flags & P_LEAF2) {
                        nodekey.mv_size = mc->mc_db->md_pad;
-                       nodekey.mv_data = LEAF2KEY(mc->mc_pg[mc->mc_top], 0, nodekey.mv_size);
+                       nodekey.mv_data = LEAF2KEY(mp, 0, nodekey.mv_size);
                } else {
-                       leaf = NODEPTR(mc->mc_pg[mc->mc_top], 0);
+                       leaf = NODEPTR(mp, 0);
                        MDB_SET_KEY(leaf, &nodekey);
                }
                rc = mc->mc_dbx->md_cmp(key, &nodekey);
@@ -2891,26 +2902,29 @@ mdb_cursor_set(MDB_cursor *mc, MDB_val *key, MDB_val *data,
                         * was the one we wanted.
                         */
                        mc->mc_ki[mc->mc_top] = 0;
-set1:
+                       leaf = NODEPTR(mp, 0);
                        if (exactp)
                                *exactp = 1;
-                       leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
-                       goto set3;
+                       goto set1;
                }
                if (rc > 0) {
                        unsigned int i;
-                       if (NUMKEYS(mc->mc_pg[mc->mc_top]) > 1) {
-                               if (mc->mc_pg[mc->mc_top]->mp_flags & P_LEAF2) {
-                                       nodekey.mv_data = LEAF2KEY(mc->mc_pg[mc->mc_top],
-                                                NUMKEYS(mc->mc_pg[mc->mc_top])-1, nodekey.mv_size);
+                       unsigned int nkeys = NUMKEYS(mp);
+                       if (nkeys > 1) {
+                               if (mp->mp_flags & P_LEAF2) {
+                                       nodekey.mv_data = LEAF2KEY(mp,
+                                                nkeys-1, nodekey.mv_size);
                                } else {
-                                       leaf = NODEPTR(mc->mc_pg[mc->mc_top], NUMKEYS(mc->mc_pg[mc->mc_top])-1);
+                                       leaf = NODEPTR(mp, nkeys-1);
                                        MDB_SET_KEY(leaf, &nodekey);
                                }
                                rc = mc->mc_dbx->md_cmp(key, &nodekey);
                                if (rc == 0) {
                                        /* last node was the one we wanted */
-                                       mc->mc_ki[mc->mc_top] = NUMKEYS(mc->mc_pg[mc->mc_top])-1;
+                                       mc->mc_ki[mc->mc_top] = nkeys-1;
+                                       leaf = NODEPTR(mp, nkeys-1);
+                                       if (exactp)
+                                               *exactp = 1;
                                        goto set1;
                                }
                                if (rc < 0) {
@@ -2928,7 +2942,7 @@ set1:
                                        break;
                        if (i == mc->mc_top) {
                                /* There are no other pages */
-                               mc->mc_ki[mc->mc_top] = NUMKEYS(mc->mc_pg[mc->mc_top]);
+                               mc->mc_ki[mc->mc_top] = nkeys;
                                return MDB_NOTFOUND;
                        }
                }
@@ -2938,7 +2952,8 @@ set1:
        if (rc != MDB_SUCCESS)
                return rc;
 
-       assert(IS_LEAF(mc->mc_pg[mc->mc_top]));
+       mp = mc->mc_pg[mc->mc_top];
+       assert(IS_LEAF(mp));
 
 set2:
        leaf = mdb_search_node(mc, key, exactp);
@@ -2951,18 +2966,18 @@ set2:
                DPUTS("===> inexact leaf not found, goto sibling");
                if ((rc = mdb_sibling(mc, 1)) != MDB_SUCCESS)
                        return rc;              /* no entries matched */
-               mc->mc_ki[mc->mc_top] = 0;
-               assert(IS_LEAF(mc->mc_pg[mc->mc_top]));
-               leaf = NODEPTR(mc->mc_pg[mc->mc_top], 0);
+               mp = mc->mc_pg[mc->mc_top];
+               assert(IS_LEAF(mp));
+               leaf = NODEPTR(mp, 0);
        }
 
-set3:
+set1:
        mc->mc_flags |= C_INITIALIZED;
        mc->mc_flags &= ~C_EOF;
 
-       if (IS_LEAF2(mc->mc_pg[mc->mc_top])) {
+       if (IS_LEAF2(mp)) {
                key->mv_size = mc->mc_db->md_pad;
-               key->mv_data = LEAF2KEY(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top], key->mv_size);
+               key->mv_data = LEAF2KEY(mp, mc->mc_ki[mc->mc_top], key->mv_size);
                return MDB_SUCCESS;
        }
 
@@ -3731,6 +3746,8 @@ mdb_xcursor_init1(MDB_cursor *mc, MDB_node *node)
        mx->mx_dbx.md_name.mv_size = node->mn_ksize;
        mx->mx_cursor.mc_snum = 0;
        mx->mx_cursor.mc_flags = 0;
+       if (mx->mx_dbx.md_cmp == intcmp && mx->mx_db.md_pad == sizeof(size_t))
+               mx->mx_dbx.md_cmp = longcmp;
 }
 
 static void