diff options
| -rw-r--r-- | calculate_average_jatingala.sh | 23 | ||||
| -rw-r--r-- | src/main/java/dev/morling/onebrc/CalculateAverage_jatingala.java | 154 |
2 files changed, 177 insertions, 0 deletions
diff --git a/calculate_average_jatingala.sh b/calculate_average_jatingala.sh new file mode 100644 index 0000000..3b163a7 --- /dev/null +++ b/calculate_average_jatingala.sh @@ -0,0 +1,23 @@ +#!/bin/sh +# +# Copyright 2023 The original authors +# +# 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. +# + +# Uncomment below to use sdk +source "$HOME/.sdkman/bin/sdkman-init.sh" +sdk use java 21.0.1-graal 1>&2 + +JAVA_OPTS="--enable-preview" +time java $JAVA_OPTS --class-path target/average-1.0.0-SNAPSHOT.jar dev.morling.onebrc.CalculateAverage_jatingala diff --git a/src/main/java/dev/morling/onebrc/CalculateAverage_jatingala.java b/src/main/java/dev/morling/onebrc/CalculateAverage_jatingala.java new file mode 100644 index 0000000..8eca51c --- /dev/null +++ b/src/main/java/dev/morling/onebrc/CalculateAverage_jatingala.java @@ -0,0 +1,154 @@ +/* + * Copyright 2023 The original authors + * + * 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 dev.morling.onebrc; + +import java.io.ByteArrayOutputStream; +import java.io.IOException; +import java.io.RandomAccessFile; +import java.nio.MappedByteBuffer; +import java.nio.channels.FileChannel; +import java.util.*; + +public class CalculateAverage_jatingala { + + private static final String FILE = "./measurements.txt"; + + public static void main(final String[] args) throws IOException { + final int processorCount = Math.max(Runtime.getRuntime().availableProcessors(), 8); + + try (final RandomAccessFile randomAccessFile = new RandomAccessFile(FILE, "r")) { + final long[][] chunks = getChunkPositions(randomAccessFile, processorCount); + final Map<String, Statistics> result = Arrays.stream(chunks) + .parallel() + .map(chunk -> { + try { + final MappedByteBuffer mappedByteBuffer = randomAccessFile.getChannel().map(FileChannel.MapMode.READ_ONLY, chunk[0], chunk[1]); + return consumeChunk(mappedByteBuffer); + } + catch (final Exception e) { + System.out.println(e.getMessage()); + return new HashMap<String, Statistics>(); + } + }) + .reduce((a, b) -> { + a.forEach((k, v) -> { + final Statistics s = b.get(k); + if (s != null) + v.merge(s); + }); + b.forEach(a::putIfAbsent); + return a; + }) + .orElseGet(Collections::emptyMap); + + System.out.println(new TreeMap<>(result)); + } + } + + private static long[][] getChunkPositions(final RandomAccessFile file, final int chunks) throws IOException { + final long[][] result = new long[chunks][]; + + final long fileSize = file.length(); + final long chunkSize = Math.ceilDiv(fileSize, chunks); + long chunkStartPosition = 0; + for (int i = 0; i < chunks; i++) { + file.seek(Math.min(chunkStartPosition + chunkSize, fileSize)); + + while (file.getFilePointer() < fileSize && file.readByte() != '\n') { + // find next newline, noop + } + + // startPointer & length + result[i] = new long[]{ chunkStartPosition, file.getFilePointer() - chunkStartPosition }; + chunkStartPosition = file.getFilePointer(); + } + + return result; + } + + private static Map<String, Statistics> consumeChunk(final MappedByteBuffer mappedByteBuffer) { + final Map<String, Statistics> statisticsMap = new HashMap<>(); + + while (mappedByteBuffer.hasRemaining()) { + final String key = parseKey(mappedByteBuffer); + final double value = parseNumber(mappedByteBuffer); + statisticsMap.computeIfAbsent(key, _ -> new Statistics()).update(value); + } + + return statisticsMap; + } + + private static String parseKey(final MappedByteBuffer mappedByteBuffer) { + final ByteArrayOutputStream keyBytes = new ByteArrayOutputStream(); + while (mappedByteBuffer.hasRemaining()) { + final byte val = mappedByteBuffer.get(); + if (val == ';') + break; + keyBytes.write(val); + } + return keyBytes.toString(); + } + + private static double parseNumber(final MappedByteBuffer mappedByteBuffer) { + boolean negate = false; + int temp = 0; + while (mappedByteBuffer.hasRemaining()) { + final byte val = mappedByteBuffer.get(); + + if (val == '\n') + break; + if (val == '-') { + negate = true; + continue; + } + if (val == '.') + continue; + + temp = 10 * temp + (val - '0'); + } + return (negate ? -1 : 1) * (temp / 10.0); + } + + private static class Statistics { + private double min = Double.POSITIVE_INFINITY; + private double max = Double.NEGATIVE_INFINITY; + private double sum; + private long count; + + private static double round(final double value) { + return Math.round(value * 10.0) / 10.0; + } + + public void update(final double reading) { + this.min = Math.min(min, reading); + this.max = Math.max(max, reading); + this.sum += reading; + ++count; + } + + public void merge(final Statistics other) { + this.min = Math.min(min, other.min); + this.max = Math.max(max, other.max); + this.sum += other.sum; + this.count += other.count; + } + + @Override + public String toString() { + return STR."\{round(min)}/\{round(sum / count)}/\{round(max)}"; + } + } +} |