Playground/1brc
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Eliminate duplicate station names

Browse Source
This commit is contained in:
Marko Topolnik 2024-01-05 12:56:09 +01:00 committed by Gunnar Morling
parent 0f1f204a0d
commit 816e59b678
1 changed files with 21 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

27
src/main/java/dev/morling/onebrc/CreateMeasurements3.java
View File

@ -19,8 +19,10 @@ import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.StringReader;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.concurrent.ThreadLocalRandom;
public class CreateMeasurements3 {
@ -78,6 +80,7 @@ public class CreateMeasurements3 {
}
}
final var weatherStations = new ArrayList<WeatherStation>();
final var names = new HashSet<String>();
var minLen = Integer.MAX_VALUE;
var maxLen = Integer.MIN_VALUE;
try (var rows = new BufferedReader(new FileReader("data/weather_stations.csv"))) {
@ -104,18 +107,15 @@ public class CreateMeasurements3 {
}
var name = new String(buf, 0, nameLen).trim();
while (name.length() < nameLen) {
var n = nameSource.read();
if (n == -1) {
throw new Exception("Name source exhausted");
}
var ch = (char) n;
if (ch != ' ') {
name += ch;
name += readNonSpace(nameSource);
}
while (names.contains(name)) {
name = name.substring(1) + readNonSpace(nameSource);
}
if (name.indexOf(';') != -1) {
throw new Exception("Station name contains a semicolon!");
}
names.add(name);
var lat = Float.parseFloat(row.substring(row.indexOf(';') + 1));
// Guesstimate mean temperature using cosine of latitude
var avgTemp = (float) (30 * Math.cos(Math.toRadians(lat))) - 10;
@ -125,4 +125,17 @@ public class CreateMeasurements3 {
System.out.format("Generated %,d station names with length from %,d to %,d%n", KEYSET_SIZE, minLen, maxLen);
return weatherStations;
}
private static char readNonSpace(StringReader nameSource) throws IOException {
while (true) {
var n = nameSource.read();
if (n == -1) {
throw new IOException("Name source exhausted");
}
var ch = (char) n;
if (ch != ' ') {
return ch;
}
}
}
}