From e5f41ce56bc1cb0c62378e91469e5674915cb192 Mon Sep 17 00:00:00 2001 From: Hallvard Furuseth Date: Sat, 4 Jul 2015 13:48:05 +0200 Subject: [PATCH] Simpler mdb_node_shrink() --- libraries/liblmdb/mdb.c | 37 +++++++++++++++---------------------- 1 file changed, 15 insertions(+), 22 deletions(-) diff --git a/libraries/liblmdb/mdb.c b/libraries/liblmdb/mdb.c index 80a6eb977f..774ba9021b 100644 --- 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 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; } -- 2.39.2