/**
* Evaluates the full-text match.
*
* @param qc query context
* @return number of tokens, used for scoring
* @throws QueryException query exception
*/
private int contains(final QueryContext qc) throws QueryException {
first = true;
final FTLexer lexer = ftt.lexer(qc.ftToken);
// use faster evaluation for default options
int num = 0;
if (fast) {
for (final byte[] t : tokens) {
final FTTokens qtok = ftt.cache(t);
num = Math.max(num, ftt.contains(qtok, lexer) * qtok.length());
}
return num;
}
// find and count all occurrences
final boolean all = mode == FTMode.ALL || mode == FTMode.ALL_WORDS;
int oc = 0;
for (final byte[] w : unique(tokens(qc))) {
final FTTokens qtok = ftt.cache(w);
final int o = ftt.contains(qtok, lexer);
if (all && o == 0) return 0;
num = Math.max(num, o * qtok.length());
oc += o;
}
// check if occurrences are in valid range. if yes, return number of tokens
final long mn = occ != null ? toLong(occ[0], qc) : 1;
final long mx = occ != null ? toLong(occ[1], qc) : Long.MAX_VALUE;
if (mn == 0 && oc == 0) matches = FTNot.not(matches);
return oc >= mn && oc <= mx ? Math.max(1, num) : 0;
}
@Override
public boolean indexAccessible(final IndexInfo ii) {
/* If the following conditions yield true, the index is accessed:
* - all query terms are statically available
* - no FTTimes option is specified
* - explicitly set case, diacritics and stemming match options do not
* conflict with index options. */
data = ii.ic.data;
final MetaData md = data.meta;
final FTOpt fto = ftt.opt;
/* Index will be applied if no explicit match options have been set
* that conflict with the index options. As a consequence, though, index-
* based querying might yield other results than sequential scanning. */
if (occ != null
|| fto.cs != null && md.casesens == (fto.cs == FTCase.INSENSITIVE)
|| fto.isSet(DC) && md.diacritics != fto.is(DC)
|| fto.isSet(ST) && md.stemming != fto.is(ST)
|| fto.ln != null && !fto.ln.equals(md.language)) return false;
// adopt database options to tokenizer
fto.copy(md);
// estimate costs if text is not known at compile time
if (tokens == null) {
ii.costs = Math.max(2, data.meta.size / 30);
return true;
}
// summarize number of hits; break loop if no hits are expected
final FTLexer ft = new FTLexer(fto);
ii.costs = 0;
for (byte[] t : tokens) {
ft.init(t);
while (ft.hasNext()) {
final byte[] tok = ft.nextToken();
if (fto.sw != null && fto.sw.contains(tok)) continue;
if (fto.is(WC)) {
// don't use index if one of the terms starts with a wildcard
t = ft.get();
if (t[0] == '.') return false;
// don't use index if certain characters or more than 1 dot are found
int d = 0;
for (final byte w : t) {
if (w == '{' || w == '\\' || w == '.' && ++d > 1) return false;
}
}
// favor full-text index requests over exact queries
final int costs = data.costs(ft);
if (costs != 0) ii.costs += Math.max(2, costs / 100);
}
}
return true;
}
/**
* Returns a pre value.
*
* @param id unique node id
* @return pre value or -1 if id was not found
*/
final int preold(final int id) {
// find pre value in table
for (int p = Math.max(0, id); p < meta.size; ++p) if (id == id(p)) return p;
final int ps = Math.min(meta.size, id);
for (int p = 0; p < ps; ++p) if (id == id(p)) return p;
// id not found
return -1;
}
@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;
}
/**
* 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;
}
/**
* Prints the current stack trace to System.err.
*
* @param i number of steps to print
*/
public static void stack(final int i) {
errln("You're here:");
final String[] stack = toArray(new Throwable());
final int l = Math.min(Math.max(2, i + 2), stack.length);
for (int s = 2; s < l; ++s) errln(stack[s]);
}
/**
* Analyzes the specified patterns.
*
* @param patterns patterns
* @return picture variables
*/
private Picture[] analyze(final byte[][] patterns) {
// pictures
final int picL = patterns.length;
final Picture[] pics = new Picture[picL];
// analyze patterns
for (int p = 0; p < picL; p++) {
final byte[] pt = patterns[p];
final Picture pic = new Picture();
// position (integer/fractional)
int pos = 0;
// active character found
boolean act = false;
// number of characters after exponent
int exp = -1;
// number of optional characters
final int[] opt = new int[2];
// loop through all characters
final int pl = pt.length;
for (int i = 0, cl; i < pl; i += cl) {
final int ch = ch(pt, i);
cl = cl(pt, i);
boolean active = contains(actives, ch);
if (ch == decimal) {
++pos;
act = false;
} else if (ch == optional) {
opt[pos]++;
} else if (ch == exponent) {
if (act && containsActive(pt, i + cl)) {
exp = 0;
} else {
active = false;
}
} else if (ch == grouping) {
if (pos == 0) pic.group[pos] = Array.add(pic.group[pos], pic.min[pos] + opt[pos]);
} else if (contains(digits, ch)) {
if (exp == -1) pic.min[pos]++;
else exp++;
}
if (active) {
act = true;
} else {
// passive characters
pic.pc |= ch == percent;
pic.pm |= ch == permille;
// prefixes/suffixes
pic.prefSuf[pos == 0 && act ? pos + 1 : pos].add(ch);
}
}
// finalize integer-part-grouping-positions
final int[] igp = pic.group[0];
final int igl = igp.length;
for (int g = 0; g < igl; ++g) igp[g] = pic.min[0] + opt[0] - igp[g];
// check if integer-part-grouping-positions are regular
// if yes, they are replaced with a single position
if (igl > 1) {
boolean reg = true;
final int i = igp[igl - 1];
for (int g = igl - 2; g >= 0; --g) reg &= i * igl == igp[g];
if (reg) pic.group[0] = new int[] {i};
}
pic.maxFrac = pic.min[1] + opt[1];
pic.minExp = Math.max(0, exp);
pics[p] = pic;
}
return pics;
}
