diff options
Diffstat (limited to 'node.go')
| -rw-r--r-- | node.go | 51 |
1 files changed, 51 insertions, 0 deletions
@@ -38,3 +38,54 @@ func (n *node) size() int { // TODO: #define MDB_GET_KEY(node, keyptr) { if ((keyptr) != NULL) { (keyptr)->mv_size = NODEKSZ(node); (keyptr)->mv_data = NODEKEY(node); } } // TODO: #define MDB_GET_KEY2(node, key) { key.mv_size = NODEKSZ(node); key.mv_data = NODEKEY(node); } + +// Compact the main page after deleting a node on a subpage. +// @param[in] mp The main page to operate on. +// @param[in] indx The index of the subpage on the main page. +func (n *node) shrink(index int) { + /* + MDB_node *node; + MDB_page *sp, *xp; + char *base; + int nsize, delta; + indx_t i, numkeys, ptr; + + node = NODEPTR(mp, indx); + sp = (MDB_page *)NODEDATA(node); + delta = SIZELEFT(sp); + xp = (MDB_page *)((char *)sp + delta); + + // shift subpage upward + if (IS_LEAF2(sp)) { + nsize = NUMKEYS(sp) * sp->mp_pad; + 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->mp_ptrs[i] = sp->mp_ptrs[i] - delta; + } + 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; + SETDSZ(node, nsize); + + // shift lower nodes upward + ptr = mp->mp_ptrs[indx]; + numkeys = NUMKEYS(mp); + for (i = 0; i < numkeys; i++) { + if (mp->mp_ptrs[i] <= ptr) + mp->mp_ptrs[i] += delta; + } + + base = (char *)mp + mp->mp_upper; + memmove(base + delta, base, ptr - mp->mp_upper + NODESIZE + NODEKSZ(node)); + mp->mp_upper += delta; + */ +} |