io.deephaven.engine.table.impl.join.dupcompact.ByteReverseDupCompactKernel 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 CharDupCompactKernel and regenerate
 * ---------------------------------------------------------------------------------------------------------------------
 */
package io.deephaven.engine.table.impl.join.dupcompact;

import io.deephaven.chunk.*;
import io.deephaven.chunk.attributes.Any;
import io.deephaven.chunk.attributes.ChunkPositions;
import io.deephaven.engine.rowset.chunkattributes.RowKeys;
import org.jetbrains.annotations.NotNull;

public class ByteReverseDupCompactKernel implements DupCompactKernel {

    static final ByteReverseDupCompactKernel INSTANCE = new ByteReverseDupCompactKernel();

    private ByteReverseDupCompactKernel() {
        // Use the singleton INSTANCE
    }

    @Override
    public int compactDuplicates(
            @NotNull final WritableChunk chunkToCompact,
            @NotNull final WritableLongChunk rowKeys) {
        return compactDuplicates(chunkToCompact.asWritableByteChunk(), rowKeys);
    }

    @Override
    public int compactDuplicatesPreferFirst(
            @NotNull final WritableChunk chunkToCompact,
            @NotNull final WritableIntChunk chunkPositions) {
        return compactDuplicatesPreferFirst(chunkToCompact.asWritableByteChunk(), chunkPositions);
    }

    private static int compactDuplicates(
            @NotNull final WritableByteChunk chunkToCompact,
            @NotNull final WritableLongChunk rowKeys) {
        final int inputSize = chunkToCompact.size();
        if (inputSize == 0) {
            return -1;
        }

        int wpos = 0;
        int rpos = 0;

        byte last = chunkToCompact.get(0);

        while (rpos < inputSize) {
            final byte current = chunkToCompact.get(rpos);
            if (!leq(last, current)) {
                return rpos;
            }
            last = current;

            while (rpos < inputSize - 1 && eq(current, chunkToCompact.get(rpos + 1))) {
                rpos++;
            }
            chunkToCompact.set(wpos, current);
            rowKeys.set(wpos, rowKeys.get(rpos));
            rpos++;
            wpos++;
        }
        chunkToCompact.setSize(wpos);
        rowKeys.setSize(wpos);

        return -1;
    }

    private static int compactDuplicatesPreferFirst(
            @NotNull final WritableByteChunk chunkToCompact,
            @NotNull final WritableIntChunk chunkPositions) {
        final int inputSize = chunkToCompact.size();
        if (inputSize == 0) {
            return -1;
        }

        int wpos = 0;
        int rpos = 0;

        byte last = chunkToCompact.get(0);

        while (rpos < inputSize) {
            final byte current = chunkToCompact.get(rpos);
            if (!leq(last, current)) {
                return rpos;
            }
            last = current;

            chunkToCompact.set(wpos, current);
            chunkPositions.set(wpos, chunkPositions.get(rpos));
            rpos++;
            wpos++;

            while (rpos < inputSize && eq(current, chunkToCompact.get(rpos))) {
                rpos++;
            }
        }
        chunkToCompact.setSize(wpos);
        chunkPositions.setSize(wpos);

        return -1;
    }

    // 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 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
    }
}