PAGEHDRSZ
max = bt->head.psize - PAGEHDRSZ;
#define METADATA(p) ((void *)((char *)p + PAGEHDRSZ))
mp->page->lower = PAGEHDRSZ;
max = bt->head.psize - PAGEHDRSZ;
memset(&mp->page->ptrs, 0, bt->head.psize - PAGEHDRSZ);
mp->page->lower = PAGEHDRSZ;
#define NUMKEYSP(p) (((p)->lower - PAGEHDRSZ) >> 1)
#define NUMKEYS(mp) (((mp)->page->lower - PAGEHDRSZ) >> 1)
#define PAGEFILL(bt, mp) (1000 * ((bt)->head.psize - PAGEHDRSZ - SIZELEFT(mp)) / \
((bt)->head.psize - PAGEHDRSZ))