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/*******************************************************************************
 *    ___                  _   ____  ____
 *   / _ \ _   _  ___  ___| |_|  _ \| __ )
 *  | | | | | | |/ _ \/ __| __| | | |  _ \
 *  | |_| | |_| |  __/\__ \ |_| |_| | |_) |
 *   \__\_\\__,_|\___||___/\__|____/|____/
 *
 * Copyright (C) 2014-2019 Appsicle
 *
 * This program is free software: you can redistribute it and/or  modify
 * it under the terms of the GNU Affero General Public License, version 3,
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see .
 *
 ******************************************************************************/

package com.questdb.cairo;


import com.questdb.cairo.sql.RowCursor;

public class BitmapIndexFwdNullReader implements BitmapIndexReader {

    private final NullCursor cursor = new NullCursor();

    @Override
    public RowCursor getCursor(boolean cachedInstance, int key, long minValue, long maxValue) {
        final NullCursor cursor = getCursor(cachedInstance);
        cursor.max = maxValue + 1;
        cursor.value = 0;
        return cursor;
    }

    @Override
    public int getKeyCount() {
        return 1;
    }

    @Override
    public boolean isOpen() {
        return true;
    }

    private NullCursor getCursor(boolean cachedInstance) {
        return cachedInstance ? cursor : new NullCursor();
    }

    private static class NullCursor implements RowCursor {
        private long max;
        private long value;

        @Override
        public boolean hasNext() {
            return value < max;
        }

        @Override
        public long next() {
            return value++;
        }
    }
}