/*
 * Copyright (c) 2023-2024 nosqlbench
 *
 * Licensed 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.
 */

package io.nosqlbench.virtdata.lib.vectors.primitive;

import io.nosqlbench.virtdata.api.annotations.Categories;
import io.nosqlbench.virtdata.api.annotations.Category;
import io.nosqlbench.virtdata.api.annotations.ThreadSafeMapper;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

/**
 * Precompute the interior double[] values to use as a LUT.
 */
@ThreadSafeMapper
@Categories(Category.experimental)
public class DoubleCache extends DoubleSequence {
    private final static Logger logger = LogManager.getLogger(DoubleCache.class);
    private final double[] cache;

    public DoubleCache(DoubleSequence sequence) {
        super(sequence.cardinality);
        if (sequence.cardinality > 1000000) {
            logger.warn("initializing cache with " + sequence.cardinality + " elements, which seems high.");
        }
        this.cache = new double[(int) sequence.getCardinality()];
        for (int i = 0; i < cache.length; i++) {
            this.cache[i] = sequence.applyAsDouble(i);
        }
    }

    @Override
    public double applyAsDouble(long value) {
        return cache[(int)(value%cache.length)];
    }
}
