Simpler mdb_node_shrink()

diff --git a/libraries/liblmdb/mdb.c b/libraries/liblmdb/mdb.c
index 80a6eb977f0d47c9059f3ac13c5907c59264330c..774ba9021b0782d902af80f4485cd6bc99fa741a 100644 (file)
--- a/libraries/liblmdb/mdb.c
+++ b/libraries/liblmdb/mdb.c
@@ -7104,45 +7104,38 @@ mdb_node_shrink(MDB_page *mp, indx_t indx)
        MDB_node *node;
        MDB_page *sp, *xp;
        char *base;
-       int nsize, delta;
-       indx_t           i, numkeys, ptr;
+       indx_t delta, nsize, len, ptr;
+       int i;
 
        node = NODEPTR(mp, indx);
        sp = (MDB_page *)NODEDATA(node);
        delta = SIZELEFT(sp);
-       xp = (MDB_page *)((char *)sp + delta);
+       nsize = NODEDSZ(node) - delta;
 
-       /* shift subpage upward */
+       /* Prepare to shift upward, set len = length(subpage part to shift) */
        if (IS_LEAF2(sp)) {
-               nsize = NUMKEYS(sp) * sp->mp_pad;
+               len = nsize;
                if (nsize & 1)
                        return;         /* do not make the node uneven-sized */
-               memmove(METADATA(xp), METADATA(sp), nsize);
        } else {
-               int i;
-               numkeys = NUMKEYS(sp);
-               for (i=numkeys-1; i>=0; i--)
+               xp = (MDB_page *)((char *)sp + delta); /* destination subpage */
+               for (i = NUMKEYS(sp); --i >= 0; )
                        xp->mp_ptrs[i] = sp->mp_ptrs[i] - delta;
+               len = PAGEHDRSZ;
        }
-       xp->mp_upper = sp->mp_lower;
-       xp->mp_lower = sp->mp_lower;
-       xp->mp_flags = sp->mp_flags;
-       xp->mp_pad = sp->mp_pad;
-       COPY_PGNO(xp->mp_pgno, mp->mp_pgno);
-
-       nsize = NODEDSZ(node) - delta;
+       sp->mp_upper = sp->mp_lower;
+       COPY_PGNO(sp->mp_pgno, mp->mp_pgno);
        SETDSZ(node, nsize);
 
-       /* shift lower nodes upward */
+       /* Shift <lower nodes...initial part of subpage> upward */
+       base = (char *)mp + mp->mp_upper + PAGEBASE;
+       memmove(base + delta, base, (char *)sp + len - base);
+
        ptr = mp->mp_ptrs[indx];
-       numkeys = NUMKEYS(mp);
-       for (i = 0; i < numkeys; i++) {
+       for (i = NUMKEYS(mp); --i >= 0; ) {
                if (mp->mp_ptrs[i] <= ptr)
                        mp->mp_ptrs[i] += delta;
        }
-
-       base = (char *)mp + mp->mp_upper + PAGEBASE;
-       memmove(base + delta, base, ptr - mp->mp_upper + NODESIZE + NODEKSZ(node));
        mp->mp_upper += delta;
 }