/**
* Performs a wildcard search for the specified token.
*
* @param token token to look for
* @return iterator
*/
private synchronized IndexIterator wc(final byte[] token) {
final FTIndexIterator it = FTIndexIterator.FTEMPTY;
final FTWildcard wc = new FTWildcard(token);
if (!wc.parse()) return it;
final IntList pr = new IntList();
final IntList ps = new IntList();
final byte[] pref = wc.prefix();
final int pl = pref.length, tl = tp.length;
final int l = Math.min(tl - 1, wc.max());
for (int ti = pl; ti <= l; ti++) {
int i = tp[ti];
if (i == -1) continue;
int c = ti + 1;
int e = -1;
while (c < tl && e == -1) e = tp[c++];
i = find(pref, i, e, ti);
while (i < e) {
final byte[] t = inY.readBytes(i, ti);
if (!startsWith(t, pref)) break;
if (wc.match(t)) {
inZ.cursor(pointer(i, ti));
final int s = size(i, ti);
for (int d = 0; d < s; d++) {
pr.add(inZ.readNum());
ps.add(inZ.readNum());
}
}
i += ti + ENTRY;
}
}
return iter(new FTCache(pr, ps), token);
}
/**
* Performs a fuzzy search for the specified token with a maximum number of errors.
*
* @param token token to look for
* @param k number of errors allowed
* @return iterator
*/
private synchronized IndexIterator fuzzy(final byte[] token, final int k) {
FTIndexIterator it = FTIndexIterator.FTEMPTY;
final int tokl = token.length, tl = tp.length;
final int e = Math.min(tl - 1, tokl + k);
int s = Math.max(1, tokl - k) - 1;
while (++s <= e) {
int p = tp[s];
if (p == -1) continue;
int t = s + 1, r = -1;
while (t < tl && r == -1) r = tp[t++];
while (p < r) {
if (ls.similar(inY.readBytes(p, s), token, k)) {
it = FTIndexIterator.union(iter(pointer(p, s), size(p, s), inZ, token), it);
}
p += s + ENTRY;
}
}
return it;
}
@Override
public synchronized int costs(final IndexToken it) {
final byte[] tok = it.get();
if (tok.length > data.meta.maxlen) return Integer.MAX_VALUE;
// estimate costs for queries which stretch over multiple index entries
final FTOpt opt = ((FTLexer) it).ftOpt();
if (opt.is(FZ) || opt.is(WC)) return Math.max(1, data.meta.size >> 4);
return entry(tok).size;
}
