Paweł Adamski - 1brc submission (#629)

* Paweł Adamski - 1BRC challenge

* Paweł Adamski - 1BRC challenge

* Make files executabe

calculate_average_PawelAdamski.sh

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+#!/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.
+#
+
+JAVA_OPTS="-Xnoclassgc"
+java $JAVA_OPTS --class-path target/average-1.0.0-SNAPSHOT.jar dev.morling.onebrc.CalculateAverage_PawelAdamski

prepare_PawelAdamski.sh

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+#!/bin/bash
+#
+#  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

src/main/java/dev/morling/onebrc/CalculateAverage_PawelAdamski.java

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+/*
+ *  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.IOException;
+import java.io.RandomAccessFile;
+import java.nio.channels.FileChannel;
+import java.util.*;
+import java.util.stream.Collectors;
+
+import static java.nio.charset.StandardCharsets.UTF_8;
+import static java.util.stream.Collectors.groupingByConcurrent;
+
+public class CalculateAverage_PawelAdamski {
+
+    private static final long READ_SIZE = 100_000_000;
+    private static final String FILE = "./measurements.txt";
+
+    private static record ResultRow(double min, double mean, double max) {
+
+        public ResultRow(MeasurementAggregator ma) {
+            this(ma.min / 10.0, ((Math.round(ma.sum * 100.0) / 100.0) / (double) ma.count) / 10.0, ma.max / 10.0);
+        }
+
+        public String toString() {
+            return round(min) + "/" + round(mean) + "/" + round(max);
+        }
+
+        private double round(double value) {
+            return Math.round(value * 10.0) / 10.0;
+        }
+    }
+
+    private static class Station {
+        byte[] bytes;
+        int hash;
+
+        public Station(byte[] station) {
+            this.bytes = station;
+            this.hash = Arrays.hashCode(bytes);
+        }
+
+        @Override
+        public int hashCode() {
+            return hash;
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            return Arrays.equals(bytes, ((Station) o).bytes);
+        }
+
+    }
+
+    private static class MeasurementAggregator {
+        private long min;
+        private long max;
+        private long sum;
+        private long count;
+
+        public MeasurementAggregator(long temp) {
+            min = temp;
+            max = temp;
+            sum = temp;
+            count = 1;
+        }
+
+        public MeasurementAggregator() {
+            min = Long.MAX_VALUE;
+            max = Long.MIN_VALUE;
+            sum = 0;
+            count = 0;
+        }
+
+        public MeasurementAggregator merge(MeasurementAggregator measurement) {
+            MeasurementAggregator ma = new MeasurementAggregator();
+            ma.min = Math.min(min, measurement.min);
+            ma.max = Math.max(max, measurement.max);
+            ma.sum = sum + measurement.sum;
+            ma.count = count + measurement.count;
+            return ma;
+        }
+    }
+
+    public static void main(String[] args) throws IOException {
+        try (RandomAccessFile raf = new RandomAccessFile(FILE, "r")) {
+            List<FilePart> parts = splitFileIntoParts(raf);
+            Map<Station, MeasurementAggregator> rr = calculateTemperatureStats(parts, raf);
+            Map<String, ResultRow> results = prepareResults(rr);
+            System.out.println(results);
+        }
+    }
+
+    private static Map<String, ResultRow> prepareResults(Map<Station, MeasurementAggregator> rr) {
+        Map<String, ResultRow> measurements = new TreeMap<>();
+        rr.forEach((k, v) -> measurements.put(new String(k.bytes, UTF_8), new ResultRow(v)));
+        return measurements;
+    }
+
+    private static Map<Station, MeasurementAggregator> calculateTemperatureStats(List<FilePart> parts, RandomAccessFile raf) {
+        return parts.parallelStream()
+                .map(filePart -> parse(filePart, raf))
+                .flatMap(m -> m.entrySet().stream())
+                .collect(groupingByConcurrent(
+                        Map.Entry::getKey,
+                        Collectors.reducing(
+                                new MeasurementAggregator(),
+                                Map.Entry::getValue,
+                                MeasurementAggregator::merge)));
+    }
+
+    private static ArrayList<FilePart> splitFileIntoParts(RandomAccessFile raf) throws IOException {
+        ArrayList<FilePart> parts = new ArrayList<>((int) (raf.length() / READ_SIZE));
+        long pointer = 0;
+        long nextPointer = 0;
+        long fileLength = raf.length();
+        while (pointer < fileLength) {
+            if (pointer + READ_SIZE > fileLength) {
+                nextPointer = fileLength;
+            }
+            else {
+                nextPointer = findNextLine(raf, pointer + READ_SIZE);
+            }
+            parts.add(new FilePart(pointer, nextPointer - pointer));
+            pointer = nextPointer;
+        }
+        return parts;
+    }
+
+    private static Map<Station, MeasurementAggregator> parse(FilePart filePart, RandomAccessFile raf) {
+        try {
+            byte[] bytes = readBytesFromFile(filePart, raf);
+            return parseBytesIntoStationsMap(bytes);
+        }
+        catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    private static HashMap<Station, MeasurementAggregator> parseBytesIntoStationsMap(byte[] bytes) {
+        HashMap<Station, MeasurementAggregator> measurementAggregator = new HashMap<>(500);
+        int semicolonIndex = 0;
+        int newLineIndex = -1;
+        for (int i = 0; i < bytes.length; i++) {
+            if (bytes[i] == ';') {
+                semicolonIndex = i;
+            }
+            else if (bytes[i] == '\n') {
+                byte[] station = Arrays.copyOfRange(bytes, newLineIndex + 1, semicolonIndex);
+                long temp = parseDouble(bytes, semicolonIndex + 1, i);
+                MeasurementAggregator measurement = new MeasurementAggregator(temp);
+                measurementAggregator.compute(new Station(station), (k, prevV) -> prevV == null ? measurement : prevV.merge(measurement));
+                newLineIndex = i;
+            }
+        }
+        return measurementAggregator;
+    }
+
+    private static byte[] readBytesFromFile(FilePart filePart, RandomAccessFile raf) throws IOException {
+        var bb = raf.getChannel().map(FileChannel.MapMode.READ_ONLY, filePart.start(), filePart.len());
+        byte[] bytes = new byte[bb.remaining()];
+        bb.get(bytes);
+        return bytes;
+    }
+
+    private static long parseDouble(byte[] text, int start, int end) {
+        boolean negative = false;
+        int result = 0;
+        for (int i = start; i < end; i++) {
+            byte c = text[i];
+            if (c == '-') {
+                negative = true;
+            }
+            else if (c != '.') {
+                result *= 10;
+                result += c - '0';
+            }
+        }
+        if (negative) {
+            return -result;
+        }
+        else {
+            return result;
+        }
+    }
+
+    private static long findNextLine(RandomAccessFile raf, long currentPosition) throws IOException {
+        raf.seek(currentPosition);
+        while (raf.readByte() != '\n')
+            ;
+        return raf.getFilePointer();
+    }
+
+    record FilePart(long start, long len) {
+    }
+}