Beispiel #1
0
        /// <summary>
        /// Lookup suggestions sorted by weight (descending order).
        /// </summary>
        /// <param name="collectAll">
        ///          If <c>true</c>, the routine terminates immediately when
        ///          <paramref name="num"/> suggestions have been collected. If
        ///          <c>false</c>, it will collect suggestions from all weight
        ///          arcs (needed for <see cref="LookupSortedAlphabetically"/>. </param>
        private JCG.List <Completion> LookupSortedByWeight(BytesRef key, int num, bool collectAll)
        {
            // Don't overallocate the results buffers. This also serves the purpose of
            // allowing the user of this class to request all matches using Integer.MAX_VALUE as
            // the number of results.
            JCG.List <Completion> res = new JCG.List <Completion>(Math.Min(10, num));

            BytesRef output = BytesRef.DeepCopyOf(key);

            for (int i = 0; i < rootArcs.Length; i++)
            {
                FST.Arc <object> rootArc = rootArcs[i];
                FST.Arc <object> arc     = (new FST.Arc <object>()).CopyFrom(rootArc);

                // Descend into the automaton using the key as prefix.
                if (DescendWithPrefix(arc, key))
                {
                    // A subgraph starting from the current node has the completions
                    // of the key prefix. The arc we're at is the last key's byte,
                    // so we will collect it too.
                    output.Length = key.Length - 1;
                    if (Collect(res, num, rootArc.Label, output, arc) && !collectAll)
                    {
                        // We have enough suggestions to return immediately. Keep on looking
                        // for an
                        // exact match, if requested.
                        if (exactFirst)
                        {
                            if (!CheckExistingAndReorder(res, key))
                            {
                                int exactMatchBucket = GetExactMatchStartingFromRootArc(i, key);
                                if (exactMatchBucket != -1)
                                {
                                    // Insert as the first result and truncate at num.
                                    while (res.Count >= num)
                                    {
                                        res.RemoveAt(res.Count - 1);
                                    }
                                    res.Insert(0, new Completion(key, exactMatchBucket));
                                }
                            }
                        }
                        break;
                    }
                }
            }
            return(res);
        }