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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.File;
import java.io.IOException;
import java.lang.foreign.Arena;
import java.lang.foreign.MemorySegment;
import java.lang.foreign.ValueLayout;
import java.nio.BufferUnderflowException;
import java.nio.channels.FileChannel;
import java.nio.charset.StandardCharsets;
import java.nio.file.Path;
import java.nio.file.StandardOpenOption;
import java.util.*;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorCompletionService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
public class CalculateAverage_moysesb {
private static final String FILE = "./measurements.txt";
static class ByteArray {
final byte[] value;
final int hashCode;
private ByteArray(byte[] val, int hashCode) {
this.value = val;
this.hashCode = hashCode;
}
@Override
public boolean equals(Object o) {
if (o instanceof ByteArray other) {
return this == other || hashCode == other.hashCode && Arrays.equals(value, other.value);
}
return false;
}
@Override
public int hashCode() {
return hashCode;
}
}
static final Map<ByteArray, double[]> allResults = new HashMap<>(512);
public static void main(String[] args) throws IOException, ExecutionException, InterruptedException {
int ncpus = Runtime.getRuntime().availableProcessors();
ExecutorCompletionService<Map<ByteArray, double[]>> exec = new ExecutorCompletionService<>(Executors.newFixedThreadPool(ncpus));
var file = FileChannel.open(Path.of(FILE), StandardOpenOption.READ);
File f = new File(FILE);
long fileSize = f.length();
long split = 0;
long chunkSize = Math.min(1 << 28, fileSize < 1 << 28 ? fileSize : (fileSize / ncpus));
List<Future<Map<ByteArray, double[]>>> tasks = new ArrayList<>();
while (split < fileSize) {
final long[] offset = {split};
var task = exec.submit(() -> {
try {
final Map<ByteArray, double[]> results = new HashMap<>(512);
file:
for (; ; ) {
long chunk = Math.min(fileSize - offset[0], chunkSize);
if (chunk == 0) {
return results;
}
MemorySegment mm = file.map(FileChannel.MapMode.READ_ONLY, offset[0], chunk, Arena.ofConfined());
int i = 0;
if (offset[0] > 0) {
while (mm.get(ValueLayout.JAVA_BYTE, i) != '\n') {
i++;
}
i++;
}
while (i < chunk) {
try {
byte[] city = new byte[32];
byte[] valb = new byte[16];
byte[] target = city;
double val = 0d;
int dotOffset = 0;
int l = 0;
int nameHash = 0;
for (; ; ) {
byte b = mm.get(ValueLayout.OfByte.JAVA_BYTE, i++);
if (b == ';') {
target = valb;
l = 0;
} else if (b == '\n') {
int integral = 0;
int mult = 1;
int frac = 0;
for (int ii = 0; ii < dotOffset; ii++) {
if (valb[ii] == '-') {
mult = -1;
} else {
integral = integral * 10 + (valb[ii] - '0');
}
}
for (int ii = dotOffset+1; ii < l; ii++) {
frac = frac * 10 + (valb[ii] - '0');
}
val = integral;
if (frac > 0)
val += (frac/10d);
val *= mult;
var ba = new ByteArray(city, nameHash);
var r = results.computeIfAbsent(ba, _s -> new double[]{1000, -1000, 0, 0});
r[0] = Math.min(r[0], val);
r[1] = Math.max(r[1], val);
r[2]++;
r[3] += val;
break;
} else {
if (target == city) {
nameHash = nameHash * 31 + b;
} else if (b == '.') {
dotOffset = l;
}
target[l++] = b;
}
}
} catch (BufferUnderflowException | IndexOutOfBoundsException e) {
//happens on the last segment after EOF
break file;
}
}
offset[0] += i;
}
return results;
} catch (IOException e) {
throw new RuntimeException(e);
}
});
tasks.add(task);
split += chunkSize;
}
int taken = 0;
while (taken < tasks.size()) {
Future<Map<ByteArray, double[]>> fut = exec.take();
var map = fut.get();
taken++;
if (map == null) {
continue;
}
for (Map.Entry<ByteArray, double[]> e : map.entrySet()) {
var ba = e.getKey();
var val = e.getValue();
allResults.merge(ba, val, (old, _new) -> {
old[0] = Math.min(old[0], _new[0]);
old[1] = Math.max(old[1], _new[1]);
old[2] += _new[2];
old[3] += _new[3];
return old;
});
}
}
SortedMap<String, String> sorted = new TreeMap<>();
for (Map.Entry<ByteArray, double[]> e : allResults.entrySet()) {
byte[] utf8 = e.getKey().value;
int strlen = 0;
while (utf8[strlen] != '\0') strlen++;
String city = new String(utf8, 0, strlen, StandardCharsets.UTF_8);
double[] r = e.getValue();
String fmt = FormatProcessor.FMT."%.1f\{round(r[0])}/%.1f\{round(r[3]/r[2])}/%.1f\{round(r[1])}";
sorted.put(city, fmt);
}
System.out.println(sorted);
System.exit(0);
}
private static double round(double d) {
return Math.round(d * 10.0) / 10.0;
}
}
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