/* Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

parcel Lucy;

__C__
#include "Lucy/Search/Matcher.h"

/* A wrapper for a Matcher which caches the result of Matcher_Get_Doc_ID().
 */
typedef struct lucy_HeapedMatcherDoc {
    lucy_Matcher *matcher;
    int32_t   doc;
} lucy_HeapedMatcherDoc;

#ifdef LUCY_USE_SHORT_NAMES
  #define HeapedMatcherDoc              lucy_HeapedMatcherDoc
#endif

__END_C__

/** Matcher which unions the doc id sets of other Matchers using a priority
 * queue.
 */

class Lucy::Search::ORMatcher inherits Lucy::Search::PolyMatcher {

    lucy_HeapedMatcherDoc **heap;
    lucy_HeapedMatcherDoc **pool;    /* Pool of HMDs to minimize mallocs */
    char                   *blob;    /* single allocation for all HMDs */
    lucy_HeapedMatcherDoc  *top_hmd; /* cached top elem */
    uint32_t                size;
    uint32_t                max_size;

    inert incremented ORMatcher*
    new(VArray *children);

    /**
     * @param children An array of Matchers.
     */
    inert incremented ORMatcher*
    init(ORMatcher *self, VArray *children);

    public void
    Destroy(ORMatcher *self);

    public int32_t
    Next(ORMatcher *self);

    public int32_t
    Advance(ORMatcher *self, int32_t target);

    public int32_t
    Get_Doc_ID(ORMatcher *self);
}

/**
 * Union results of multiple Matchers.
 *
 * ORScorer collates the output of multiple scoring child Matchers, summing
 * their scores whenever they match the same document.
 */
class Lucy::Search::ORScorer inherits Lucy::Search::ORMatcher {

    float            *scores;
    int32_t           doc_id;

    inert incremented ORScorer*
    new(VArray *children, Similarity *similarity);

    inert ORScorer*
    init(ORScorer *self, VArray *children, Similarity *similarity);

    public void
    Destroy(ORScorer *self);

    public int32_t
    Next(ORScorer *self);

    public int32_t
    Advance(ORScorer *self, int32_t target);

    public float
    Score(ORScorer *self);

    public int32_t
    Get_Doc_ID(ORScorer *self);
}