io.trino.orc.OrcDataSourceUtils Maven / Gradle / Ivy

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/*
 * 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.trino.orc;

import com.google.common.collect.ImmutableList;
import io.airlift.slice.Slice;
import io.airlift.units.DataSize;

import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;

import static java.lang.Math.toIntExact;
import static java.util.Comparator.comparingLong;

public final class OrcDataSourceUtils
{
    private OrcDataSourceUtils() {}

    /**
     * Merge disk ranges that are closer than {@code maxMergeDistance}.
     */
    public static List mergeAdjacentDiskRanges(Collection diskRanges, DataSize maxMergeDistance, DataSize maxReadSize)
    {
        // sort ranges by start offset
        List ranges = new ArrayList<>(diskRanges);
        ranges.sort(comparingLong(DiskRange::getOffset));

        // merge overlapping ranges
        long maxReadSizeBytes = maxReadSize.toBytes();
        long maxMergeDistanceBytes = maxMergeDistance.toBytes();
        ImmutableList.Builder result = ImmutableList.builder();
        DiskRange last = ranges.get(0);
        for (int i = 1; i < ranges.size(); i++) {
            DiskRange current = ranges.get(i);
            DiskRange merged = null;
            boolean blockTooLong = false;
            try {
                merged = last.span(current);
            }
            catch (ArithmeticException e) {
                blockTooLong = true;
            }
            if (!blockTooLong && merged.getLength() <= maxReadSizeBytes && last.getEnd() + maxMergeDistanceBytes >= current.getOffset()) {
                last = merged;
            }
            else {
                result.add(last);
                last = current;
            }
        }
        result.add(last);

        return result.build();
    }

    /**
     * Get a slice for the disk range from the provided buffers.  The buffers ranges do not have
     * to exactly match {@code diskRange}, but {@code diskRange} must be completely contained within
     * one of the buffer ranges.
     */
    public static Slice getDiskRangeSlice(DiskRange diskRange, Map buffers)
    {
        for (Entry bufferEntry : buffers.entrySet()) {
            DiskRange bufferRange = bufferEntry.getKey();
            Slice buffer = bufferEntry.getValue();
            if (bufferRange.contains(diskRange)) {
                int offset = toIntExact(diskRange.getOffset() - bufferRange.getOffset());
                return buffer.slice(offset, diskRange.getLength());
            }
        }
        throw new IllegalStateException("No matching buffer for disk range");
    }
}