1 files changed, 0 insertions, 249 deletions
diff --git a/src/main/java/dev/morling/onebrc/CalculateAverage_samuelyvon.java b/src/main/java/dev/morling/onebrc/CalculateAverage_samuelyvon.java
deleted file mode 100644
index 10a2179..0000000
--- a/src/main/java/dev/morling/onebrc/CalculateAverage_samuelyvon.java
+++ /dev/null
@@ -1,249 +0,0 @@
-/*
- *  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.MappedByteBuffer;
-import java.nio.channels.FileChannel;
-import java.nio.charset.StandardCharsets;
-import java.util.*;
-import java.util.stream.Collectors;
-
-/**
- * Samuel Yvon's entry.
- * <p>
- * Explanation behind my reasoning:
- * - I want to make it as fast as possible without it being an unreadable mess; I want to avoid bit fiddling UTF-8
- * and use the provided facilities
- * - I use the fact that we know the number of stations to optimize HashMap creation (75% rule)
- * - I stole branch-less compare from royvanrijn
- * - I assume valid ASCII encoding for the number part, which allows me to parse it manually
- * (should hold for valid UTF-8)
- * - I have not done Java in forever. Especially what the heck it's become. I've looked at the other submissions and
- * the given sample to get inspiration. I did not even know about this Stream API thing.
- * </p>
- *
- * <p>
- * Future ideas:
- * - Probably can Vector-Apirize the number parsing (but it's three to four numbers, is it worth?)
- * </p>
- *
- * <p>
- * Observations:
- * - [2024-01-09] The branch-less code from royvarijn does not have a huge impact
- * </p>
- *
- * <p>
- * Changelogs:
- * 2024-01-09: Naive multi-threaded, no floats, manual line parsing
- * </p>
- */
-public class CalculateAverage_samuelyvon {
-
-    private static final String FILE = "./measurements.txt";
-
-    private static final int MAX_STATIONS = 10000;
-
-    private static final byte SEMICOL = 0x3B;
-
-    private static final byte MINUS = '-';
-
-    private static final byte ZERO = '0';
-
-    private static final byte NEWLINE = '\n';
-
-    // The minimum line length in bytes (over-egg.)
-    private static final int MIN_LINE_LENGTH_BYTES = 200;
-
-    /**
-     * Branchless min (unprecise for large numbers, but good enough)
-     *
-     * @author royvanrijn
-     */
-    private static int branchlessMax(final int a, final int b) {
-        final int diff = a - b;
-        final int dsgn = diff >> 31;
-        return a - (diff & dsgn);
-    }
-
-    /**
-     * Branchless min (unprecise for large numbers, but good enough)
-     *
-     * @author royvanrijn
-     */
-    private static int branchlessMin(final int a, final int b) {
-        final int diff = a - b;
-        final int dsgn = diff >> 31;
-        return b + (diff & dsgn);
-    }
-
-    private static class StationMeasureAgg {
-        private int min;
-        private int max;
-        private long sum;
-        private long count;
-
-        private final String city;
-
-        public StationMeasureAgg(String city) {
-            // Actual numbers are between -99.9 and 99.9, but we *10 to avoid float
-            this.city = city;
-            min = 1000;
-            max = -1000;
-            sum = 0;
-            count = 0;
-        }
-
-        public String city() {
-            return this.city;
-        }
-
-        public StationMeasureAgg mergeWith(StationMeasureAgg other) {
-            min = branchlessMin(min, other.min);
-            max = branchlessMax(max, other.max);
-
-            sum += other.sum;
-            count += other.count;
-
-            return this;
-        }
-
-        public void accumulate(int number) {
-            min = branchlessMin(min, number);
-            max = branchlessMax(max, number);
-
-            sum += number;
-            count++;
-        }
-
-        @Override
-        public String toString() {
-            double min = Math.round((double) this.min) / 10.0;
-            double max = Math.round((double) this.max) / 10.0;
-            double mean = Math.round((((double) this.sum / this.count))) / 10.0;
-            return min + "/" + mean + "/" + max;
-        }
-    }
-
-    private static HashMap<String, StationMeasureAgg> parseChunk(MappedByteBuffer chunk) {
-        HashMap<String, StationMeasureAgg> m = HashMap.newHashMap(MAX_STATIONS);
-
-        int i = 0;
-        while (i < chunk.limit()) {
-            int j = i;
-            for (; j < chunk.limit(); ++j) {
-                // TODO: Could compute a hash here, store a byte array, and decode UTF-8 at the
-                // latest moment.
-                if (chunk.get(j) == SEMICOL) {
-                    break;
-                }
-            }
-
-            byte[] backingNameArray = new byte[j - i];
-            chunk.get(i, backingNameArray);
-            String name = new String(backingNameArray, StandardCharsets.UTF_8);
-
-            // Skip the `;`
-            j++;
-
-            // Parse the int ourselves, avoids a 'String::replace' to remove the
-            // digit.
-            int temp = 0;
-            boolean neg = chunk.get(j) == MINUS;
-            for (j = j + (neg ? 1 : 0); j < chunk.limit(); ++j) {
-                temp *= 10;
-                byte c = chunk.get(j);
-                if (c != '.') {
-                    temp += (char) (c - ZERO);
-                }
-                else {
-                    j++;
-                    break;
-                }
-            }
-
-            // The decimal point
-            temp += (char) (chunk.get(j) - ZERO);
-
-            i = j + 1;
-
-            while (chunk.get(i++) != '\n')
-                ;
-
-            if (neg)
-                temp = -temp;
-
-            m.computeIfAbsent(name, StationMeasureAgg::new).accumulate(temp);
-        }
-
-        return m;
-    }
-
-    private static int approximateChunks() {
-        // https://stackoverflow.com/a/4759606
-        // I don't remember Java :D
-        return Runtime.getRuntime().availableProcessors();
-    }
-
-    private static List<MappedByteBuffer> getFileChunks() throws IOException {
-        int approxChunkCount = approximateChunks();
-
-        List<MappedByteBuffer> fileChunks = new ArrayList<>(approxChunkCount * 2);
-
-        // Compute chunks offsets and lengths
-        try (RandomAccessFile file = new RandomAccessFile(FILE, "r")) {
-            long totalOffset = 0;
-            long fLength = file.length();
-            long approximateLength = Long.max(fLength / approxChunkCount, MIN_LINE_LENGTH_BYTES);
-
-            while (totalOffset < fLength) {
-                long offset = totalOffset;
-                int length = (int) approximateLength;
-
-                boolean eof = offset + length >= fLength;
-                if (eof) {
-                    length = (int) (fLength - offset);
-                }
-
-                MappedByteBuffer out = file.getChannel().map(FileChannel.MapMode.READ_ONLY, totalOffset, length);
-
-                while (out.get(length - 1) != NEWLINE) {
-                    length--;
-                }
-
-                out.position(0);
-                out.limit(length);
-
-                fileChunks.add(out);
-
-                totalOffset += length;
-            }
-        }
-
-        return fileChunks;
-    }
-
-    public static void main(String[] args) throws IOException {
-        var fileChunks = getFileChunks();
-
-        // Map per core, giving the non-overlapping memory slices
-        final Map<String, StationMeasureAgg> sortedMeasures = fileChunks.parallelStream().map(CalculateAverage_samuelyvon::parseChunk)
-                .flatMap(x -> x.values().stream()).collect(Collectors.toMap(StationMeasureAgg::city, x -> x, StationMeasureAgg::mergeWith, TreeMap::new));
-
-        System.out.println(sortedMeasures);
-    }
-}