Make multiplatform (#19)

* migrate to kmp (second try)

* convert app to kotlin

* for java, mark as throwing io exception

* consistent naming

* rather use CountryBoundariesUtils on java

* update readme

* use shared utility functions for test

(because there is some bug in kmp...)

* add yarn.lock

* correct name

* Revert "add yarn.lock"

This reverts commit aa73f3a.

* re-add benchmark script

but as an own module

Author: westnordost

.gitignore

@@ -3,7 +3,8 @@
 /local.properties
 /.idea
 .DS_Store
-/build
+**/build
 /captures
 .externalNativeBuild
-/boundaries.osm
+/boundaries.osm
+.kotlin

README.md

@@ -1,36 +1,58 @@
 # countryboundaries
 
-Java library to enable fast offline reverse country geocoding: Find out the country / state in which a geo position is located.
-
-It is well tested, does not have any dependencies, works well on Android and most importantly, is very fast.
-
-Requires Java 8.
+Kotlin multiplatform library to find in which region a given geo position is located fast.
 
 ## Copyright and License
 
-© 2018-2023 Tobias Zwick. This library is released under the terms of the [GNU Lesser General Public License](http://www.gnu.org/licenses/lgpl-3.0.html) (LGPL).
+© 2018-2025 Tobias Zwick. This library is released under the terms of the [GNU Lesser General Public License](http://www.gnu.org/licenses/lgpl-3.0.html) (LGPL).
 The default data used is derived from OpenStreetMap and thus © OpenStreetMap contributors and licensed under the [Open Data Commons Open Database License](https://opendatacommons.org/licenses/odbl/) (ODbL).
 
 ## Usage
 
-Add [`de.westnordost:countryboundaries:2.1`](https://mvnrepository.com/artifact/de.westnordost/countryboundaries/2.1) as a Maven dependency or download the jar from there.
+Add `de.westnordost:countryboundaries:3.0.0` as a Maven dependency or download the jar from there.
 
-```java
+```kotlin
 // load data. You should do this once and use CountryBoundaries as a singleton.
-byte[] bytes = Files.readAllBytes(new File("boundaries.ser").toPath());
-CountryBoundaries boundaries = CountryBoundaries.load(new ByteArrayInputStream(bytes));
-	
-// get country ids by position
-boundaries.getIds(-96.7954, 32.7816); // returns "US-TX","US"
-
-// check if a position is in a country
-boundaries.isIn(8.6910, 47.6973, "DE"); // returns true
+val source = FileSystem.source("boundaries.ser").buffered()
+val boundaries = source.use { CountryBoundaries.deserializeFrom(it) }
+
+// get ids of regions at position
+boundaries.getIds(
+    longitude = -96.7954,
+    latitude = 32.7816
+) // returns "US-TX","US"
+
+// check if a position is in region with specified id
+boundaries.isIn(
+    longitude = 8.6910,
+    latitude = 47.6973,
+    id = "DE"
+) // returns true
+
+// get ids of the regions that are present in the given bounds
+boundaries.getIntersectingIds(
+    minLongitude = 50.6,
+    minLatitude = 5.9,
+    maxLongitude = 50.8,
+    maxLatitude = 6.1
+) // returns "NL", "LU", "DE", "BE", "BE-VLG", "BE-WAL"
+
+// get ids of the regions that completely cover the given bounds
+boundaries.getContainingIds(
+    minLongitude = 50.6,
+    minLatitude = 5.9,
+    maxLongitude = 50.8,
+    maxLatitude = 6.1
+) // returns empty list
+```
 
-// get which country ids can be found within the given bounding box
-boundaries.getIntersectingIds(50.6, 5.9, 50.8, 6.1) // returns "NL", "LU", "DE", "BE", "BE-VLG", "BE-WAL"
+On Java, use this to load the boundaries:
 
-// get which country ids completely cover the given bounding box
-boundaries.getContainingIds(50.6, 5.9, 50.8, 6.1) // returns empty list
+```java
+CountryBoundaries boundaries = null;
+try (FileInputStream fis = new FileInputStream("boundaries.ser")) {
+  boundaries = CountryBoundariesUtils.deserializeFrom(fis);
+}
 ```
 
 The default data file is in `/data/`. Don't forget to give attribution when distributing it. See below.

benchmark/build.gradle.kts

@@ -0,0 +1,8 @@
+plugins {
+    id("java")
+    id("application")
+}
+
+dependencies {
+    implementation(project(":library"))
+}

…t/countryboundaries/PerformanceTest.java …st/countryboundaries/benchmark/Main.javalibrary/src/test/java/de/westnordost/countryboundaries/PerformanceTest.java renamed to benchmark/src/main/java/de/westnordost/countryboundaries/benchmark/Main.java library/src/test/java/de/westnordost/countryboundaries/PerformanceTest.java renamed to benchmark/src/main/java/de/westnordost/countryboundaries/benchmark/Main.java

@@ -1,18 +1,20 @@
-package de.westnordost.countryboundaries;
+package de.westnordost.countryboundaries.benchmark;
 
+import de.westnordost.countryboundaries.CountryBoundaries;
+import de.westnordost.countryboundaries.CountryBoundariesUtils;
 
 import java.io.ByteArrayInputStream;
 import java.io.File;
 import java.nio.file.Files;
 import java.util.Locale;
 import java.util.Random;
 
-public class PerformanceTest {
+public class Main {
 
     public static void main(String[] args) throws Exception {
         long time = System.nanoTime();
         byte[] bytes = Files.readAllBytes(new File("data/boundaries360x180.ser").toPath());
-        CountryBoundaries boundaries = CountryBoundaries.load(new ByteArrayInputStream(bytes));
+        CountryBoundaries boundaries = CountryBoundariesUtils.deserializeFrom(new ByteArrayInputStream(bytes));
         long timeSpentOnLoading = System.nanoTime() - time;
         System.out.println(
                 "Loading data took " +
@@ -37,11 +39,11 @@ public static void main(String[] args) throws Exception {
         long timeSpentOnBoundaries = timeSpent - timeSpentOnRandom;
 
         System.out.println(
-                "Querying " + checks + " random locations took " +
-                String.format(Locale.US, "%,.2f", timeSpentOnBoundaries * 1e-9) + " seconds " +
-                "- so on average " +
-                Math.round(timeSpentOnBoundaries * 1.0 / checks) + " nanoseconds"
+            "Querying " + checks + " random locations took " +
+            String.format(Locale.US, "%,.2f", timeSpentOnBoundaries * 1e-9) + " seconds " +
+            "- so on average " +
+            Math.round(timeSpentOnBoundaries * 1.0 / checks) + " nanoseconds"
         );
     }
 
-}
+}

build.gradle build.gradle.ktsbuild.gradle renamed to build.gradle.kts

@@ -6,17 +6,11 @@ buildscript {
         mavenCentral()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:7.4.2'
+        classpath("com.android.tools.build:gradle:8.9.2")
+        classpath(kotlin("gradle-plugin", version = "2.1.21"))
     }
 }
 
-allprojects {
-    repositories {
-        google()
-        mavenCentral()
-    }
-}
-
-tasks.register('clean', Delete) {
-    delete rootProject.buildDir
-}
+plugins {
+    id("org.jetbrains.kotlin.multiplatform") version "2.1.21" apply false
+}

generator/.gitignore

@@ -11,10 +11,7 @@
 import com.vividsolutions.jts.geom.PrecisionModel;
 import com.vividsolutions.jts.index.strtree.STRtree;
 
-import java.util.ArrayList;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
+import java.util.*;
 
 public class CountryBoundariesGenerator
 {
@@ -57,7 +54,7 @@ public CountryBoundaries generate(int width, int height, List<Geometry> boundari
 		}
 		if(listener != null) listener.onProgress(1);
 
-		return new CountryBoundaries(raster, width, geometrySizes);
+		return new CountryBoundaries(Arrays.asList(raster), width, geometrySizes);
 	}
 
 	private CountryBoundariesCell createCell(
@@ -96,7 +93,8 @@ else if(!im.isDisjoint())
 	private CountryAreas createCountryAreas(
 			String areaId, Geometry intersection, double lonMin, double latMin, double lonMax, double latMax)
 	{
-		List<Point[]> outer = new ArrayList<>(), inner = new ArrayList<>();
+		List<List<Point>> outer = new ArrayList<>();
+		List<List<Point>> inner = new ArrayList<>();
 
 		if(intersection instanceof Polygon)
 		{
@@ -120,10 +118,10 @@ private CountryAreas createCountryAreas(
 				}
 			}
 		}
-		return new CountryAreas(areaId,outer.toArray(new Point[][]{}), inner.toArray(new Point[][]{}));
+		return new CountryAreas(areaId, outer, inner);
 	}
 
-	private Point[] createPoints(LineString ring, double lonMin, double latMin, double lonMax, double latMax)
+	private List<Point> createPoints(LineString ring, double lonMin, double latMin, double lonMax, double latMax)
 	{
 		Coordinate[] coords = ring.getCoordinates();
 		// leave out last - not necessary
@@ -135,7 +133,7 @@ private Point[] createPoints(LineString ring, double lonMin, double latMin, doub
 			int y = (int) ((coord.y - latMin) * 0xffff / (latMax - latMin));
 			result[i] = new Point(x, y);
 		}
-		return result;
+		return Arrays.asList(result);
 	}
 
 	private STRtree buildIndex(List<Geometry> geometries)
@@ -171,7 +169,7 @@ private String getAreaId(Geometry g)
 		if(g instanceof Polygonal)
 		{
 			Object data = g.getUserData();
-			if(data != null && data instanceof String)
+			if(data instanceof String)
 			{
 				return (String) data;
 			}

generator/src/main/java/de/westnordost/countryboundaries/CountryBoundariesGenerator.java

@@ -5,7 +5,6 @@
 import com.vividsolutions.jts.geom.GeometryFactory;
 
 import java.io.ByteArrayOutputStream;
-import java.io.DataOutputStream;
 import java.io.FileInputStream;
 import java.io.FileOutputStream;
 import java.io.InputStreamReader;
@@ -27,7 +26,6 @@ public static void main(String[] args) throws Exception {
 			System.err.println("Missing parameters. F.e. 'boundaries.osm 360 180' or 'boundaries.osm boundaries.json' ");
 			return;
 		}
-
 		String filename = args[0];
 		FileInputStream is = new FileInputStream(filename);
 		GeometryCollection geometries;
@@ -105,8 +103,7 @@ else if(filename.endsWith(".osm"))
 		CountryBoundaries boundaries = generator.generate(width, height, geometryList);
 		try(FileOutputStream fos = new FileOutputStream("boundaries.ser"))
 		{
-			DataOutputStream dos = new DataOutputStream(fos);
-			new CountryBoundariesSerializer().write(boundaries, dos);
+			CountryBoundariesUtils.serializeTo(fos, boundaries);
 		}
 	}
 }