static bt_data_t findminnode(struct btree *btr, struct btreenode *x) {
if (x->leaf) return KEYS(btr, x)[0];
else return findminnode(btr, NODES(btr, x)[0]);
}
bt_data_t bt_min(struct btree *btr) {
return findminnode(btr, btr->root);
}
static bool btScionFind(btSIter *siter, bt_n *x, ulong ofst, bt *btr, bool asc,
cswc_t *w, long lim) {
int i = asc ? 0 : x->n; //DEBUG_SCION_PRE_LOOP1
int fin = asc ? x->n + 1 : -1;//LOOPS:(i=0,i<=x->n,i++)&(i=x->n,i>=0,i--)
while (i != fin) {
if (x->leaf) break;
uint32_t scion = NODES(btr, x)[i]->scion; //DEBUG_SCION_LOOP_1
if (scion >= ofst) {
bool i_end_n = (i == siter->x.bln->self->n);
siter->x.bln->in = i;
siter->x.bln->ik = (i_end_n) ? i - 1 : i; //DEBUG_SCION_LOOP_1_KID
if (scion == ofst) {
if (!asc) {
siter->x.bln->in = siter->x.bln->ik = i - 1;
}
return 1;
}
siter->x.bln->child = get_new_iter_child(&siter->x);
to_child(&siter->x, NODES(btr, x)[i]);
bt_n *kid = NODES(btr, x)[i]; //DEBUG_SCION_LOOP_1_GOT_KID
if (!kid->leaf) {
btScionFind(siter, kid, ofst, btr, asc, w, lim);
return 1;
} else x = kid;
break;
} else ofst -= (scion + 1); // +1 for NODE itself
i = asc ? i + 1 : i - 1; // loop increment
}
// Now Find the rest of the OFFSET (respecting DRs)
uint32 n = siter->x.bln->self->n;
i = asc ? 0 : n - 1;
fin = asc ? MIN(ofst, n) : MAX(-1, (n - ofst));
int last = asc ? n - 1 : 0;
ulong cnt = 0;
//TODO findminnode() is too inefficient -> needs to be a part of btr
bt_n *minx = findminnode(btr, btr->root);
int btdl = btr->dirty_left;
int dr = 0; //DEBUG_SCION_PRE_LOOP2
while (i != fin) {
dr = getDR(btr, x, i);
cnt += dr;
if (!i && x == minx) cnt += btdl; //DEBUG_SCION_LOOP2
if (cnt >= ofst) break;
cnt++;
i = asc ? i + 1 : i - 1; // loop increment
} //DEBUG_SCION_OFFSET_TOO_BIG
if (i == fin && i == last) {
if (cnt >= x->scion) return 0;
}
else if (cnt < ofst) return 0; //OFST 2big
siter->x.bln->ik = i;
INIT_ITER_BEENTRY(siter, btr, x, siter->x.bln->ik);
if (asc) {
if ((ofst + dr) != cnt) siter->missed = 1;
}
else {
if (!i && x == minx) {
if (ofst != (cnt - btdl)) siter->missed = 1;
}
else {
if (ofst != cnt) siter->missed = 1;
}
} //DEBUG_SCION_POST_LOOP2
return 1;
}
