io.deephaven.engine.table.impl.join.stamp.ByteNoExactReverseStampKernel Maven / Gradle / Ivy

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/**
 * Copyright (c) 2016-2022 Deephaven Data Labs and Patent Pending
 */
/*
 * ---------------------------------------------------------------------------------------------------------------------
 * AUTO-GENERATED CLASS - DO NOT EDIT MANUALLY - for any changes edit CharNoExactStampKernel and regenerate
 * ---------------------------------------------------------------------------------------------------------------------
 */
package io.deephaven.engine.table.impl.join.stamp;

import io.deephaven.chunk.*;
import io.deephaven.engine.rowset.chunkattributes.RowKeys;
import io.deephaven.chunk.attributes.Values;
import io.deephaven.engine.rowset.RowSequence;


public class ByteNoExactReverseStampKernel implements StampKernel {
    static final ByteNoExactReverseStampKernel INSTANCE = new ByteNoExactReverseStampKernel();
    private ByteNoExactReverseStampKernel() {} // static use only

    @Override
    public void computeRedirections(Chunk leftStamps, Chunk rightStamps, LongChunk rightKeyIndices, WritableLongChunk leftRedirections) {
        computeRedirections(leftStamps.asByteChunk(), rightStamps.asByteChunk(), rightKeyIndices, leftRedirections);
    }

    static private void computeRedirections(ByteChunk leftStamps, ByteChunk rightStamps, LongChunk rightKeyIndices, WritableLongChunk leftRedirections) {
        final int leftSize = leftStamps.size();
        final int rightSize = rightStamps.size();
        if (rightSize == 0) {
            leftRedirections.fillWithValue(0, leftSize, RowSequence.NULL_ROW_KEY);
            leftRedirections.setSize(leftSize);
            return;
        }

        int rightLowIdx = 0;
        byte rightLowValue = rightStamps.get(0);

        final int maxRightIdx = rightSize - 1;

        for (int li = 0; li < leftSize; ) {
            final byte leftValue = leftStamps.get(li);
            if (leq(leftValue, rightLowValue)) {
                leftRedirections.set(li++, RowSequence.NULL_ROW_KEY);
                continue;
            }

            int rightHighIdx = rightSize;

            while (rightLowIdx < rightHighIdx) {
                final int rightMidIdx = ((rightHighIdx - rightLowIdx) / 2) + rightLowIdx;
                final byte rightMidValue = rightStamps.get(rightMidIdx);
                if (lt(rightMidValue, leftValue)) {
                    rightLowIdx = rightMidIdx;
                    rightLowValue = rightMidValue;
                    if (rightLowIdx == rightHighIdx - 1) {
                        break;
                    }
                } else {
                    rightHighIdx = rightMidIdx;
                }
            }

            final long redirectionKey = rightKeyIndices.get(rightLowIdx);
            if (rightLowIdx == maxRightIdx) {
                leftRedirections.fillWithValue(li, leftSize - li, redirectionKey);
                return;
            } else {
                leftRedirections.set(li++, redirectionKey);
                final byte nextRightValue = rightStamps.get(rightLowIdx + 1);
                while (li < leftSize && lt(leftStamps.get(li), nextRightValue)) {
                    leftRedirections.set(li++, redirectionKey);
                }
            }
        }
    }
    // region comparison functions
    // note that this is a descending kernel, thus the comparisons here are backwards (e.g., the lt function is in terms of the sort direction, so is implemented by gt)
    private static int doComparison(byte lhs, byte rhs) {
        return -1 * Byte.compare(lhs, rhs);
    }
    // endregion comparison functions

    private static boolean lt(byte lhs, byte rhs) {
        return doComparison(lhs, rhs) < 0;
    }

    private static boolean leq(byte lhs, byte rhs) {
        return doComparison(lhs, rhs) <= 0;
    }

    private static boolean eq(byte lhs, byte rhs) {
        // region equality function
        return lhs == rhs;
        // endregion equality function
    }
}