/**
* Determines the pointer on a token.
*
* @param token token looking for
* @return int pointer or {@code -1} if token was not found
*/
private int token(final byte[] token) {
final int tl = token.length;
// left limit
int l = tp[tl];
if (l == -1) return -1;
int i = 1;
int r;
// find right limit
do r = tp[tl + i++];
while (r == -1);
final int x = r;
// binary search
final int o = tl + ENTRY;
while (l < r) {
final int m = l + (r - l >> 1) / o * o;
final int c = diff(inY.readBytes(m, tl), token);
if (c == 0) return m;
if (c < 0) l = m + o;
else r = m - o;
}
// accept entry if pointer is inside relevant tokens
return r != x && l == r && eq(inY.readBytes(l, tl), token) ? l : -1;
}
/**
* 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);
}
/**
* Returns an iterator for an index entry.
*
* @param off offset on entries
* @param size number of id/pos entries
* @param da data source
* @param token index token
* @return iterator
*/
private static FTIndexIterator iter(
final long off, final int size, final DataAccess da, final byte[] token) {
da.cursor(off);
final IntList pr = new IntList(size);
final IntList ps = new IntList(size);
for (int c = 0; c < size; c++) {
pr.add(da.readNum());
ps.add(da.readNum());
}
return iter(new FTCache(pr, ps), token);
}
@Override
public synchronized byte[] info(final MainOptions options) {
final TokenBuilder tb = new TokenBuilder();
final long l = inX.length() + inY.length() + inZ.length();
tb.add(LI_NAMES).add(data.meta.ftinclude).add(NL);
tb.add(LI_SIZE + Performance.format(l, true) + NL);
final IndexStats stats = new IndexStats(options.get(MainOptions.MAXSTAT));
addOccs(stats);
stats.print(tb);
return tb.finish();
}
/**
* Constructor, initializing the index structure.
*
* @param data data reference
* @throws IOException I/O Exception
*/
public FTIndex(final Data data) throws IOException {
super(data, true);
// cache token length index
inY = new DataAccess(data.meta.dbfile(DATAFTX + 'y'));
inZ = new DataAccess(data.meta.dbfile(DATAFTX + 'z'));
inX = new DataAccess(data.meta.dbfile(DATAFTX + 'x'));
tp = new int[data.meta.maxlen + 3];
final int tl = tp.length;
for (int i = 0; i < tl; ++i) tp[i] = -1;
int is = inX.readNum();
while (--is >= 0) {
int p = inX.readNum();
final int r;
if (p < tl) {
r = inX.read4();
} else {
// legacy issue (7.0.2 -> 7.1)
r = p << 24 | (inX.read1() & 0xFF) << 16 | (inX.read1() & 0xFF) << 8 | inX.read1() & 0xFF;
p = p >> 8 | 0x40;
}
tp[p] = r;
}
tp[tl - 1] = (int) inY.length();
}
/**
* Collects all tokens and their sizes found in the index structure.
*
* @param stats statistics
*/
private void addOccs(final IndexStats stats) {
int i = 0;
final int tl = tp.length;
while (i < tl && tp[i] == -1) ++i;
int p = tp[i], j = i + 1;
while (j < tl && tp[j] == -1) ++j;
final int max = tp[tl - 1];
while (p < max) {
final int oc = size(p, i);
if (stats.adding(oc)) stats.add(inY.readBytes(p, i), oc);
p += i + ENTRY;
if (p == tp[j]) {
i = j;
while (j + 1 < tl && tp[++j] == -1) ;
}
}
}
/**
* Binary search.
*
* @param token token to look for
* @param start start position
* @param end end position
* @param ti entry length
* @return position where the key was found, or would have been found
*/
private int find(final byte[] token, final int start, final int end, final int ti) {
final int tl = ti + ENTRY;
int l = 0, h = (end - start) / tl;
while (l <= h) {
final int m = l + h >>> 1;
final int p = start + m * tl;
byte[] txt = ctext.get(p);
if (txt == null) {
txt = inY.readBytes(p, ti);
ctext.put(p, txt);
}
final int d = diff(txt, token);
if (d == 0) return start + m * tl;
if (d < 0) l = m + 1;
else h = m - 1;
}
return start + l * tl;
}
/**
* 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;
}
/**
* Reads the size of ftdata from disk.
*
* @param pt pointer on token
* @param lt length of the token
* @return size of the ftdata
*/
private int size(final long pt, final int lt) {
return inY.read4(pt + lt + 5);
}
/**
* Gets the pointer on ftdata for a token.
*
* @param pt pointer on token
* @param lt length of the token
* @return int pointer on ftdata
*/
private long pointer(final long pt, final int lt) {
return inY.read5(pt + lt);
}
@Override
public synchronized void close() {
inX.close();
inY.close();
inZ.close();
}
