(feat) minimum viable implementation

.editorconfig

@@ -9,3 +9,9 @@ end_of_line = lf
 trim_trailing_whitespace = true
 insert_final_newline = true
 charset = utf-8
+
+[*.json]
+indent_size = 2
+
+[*.{yml,yaml}]
+indent_size = 2

.gitattributes

@@ -0,0 +1,5 @@
+# Gradle Wrapper script for Linux should use lf
+/gradlew text eol=lf
+
+# Gradle Wrapper script for Windows should use crlf
+/gradlew.bat text eol=crlf

.github/workflows/pull-request.yaml

@@ -0,0 +1,57 @@
+name: Pull Request
+
+on:
+  pull_request:
+    branches:
+      - main
+
+jobs:
+  build:
+    strategy:
+      matrix:
+        os: [ ubuntu-latest ]
+        java-distribution:
+          - temurin
+          - zulu
+          - adopt-hotspot
+          - adopt-openj9
+          - liberica
+          - microsoft
+          - corretto
+          - semeru
+          - oracle
+          - dragonwell
+      fail-fast: false
+
+    runs-on: ${{ matrix.os }}
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Set up "${{ matrix.java-distribution }}" JDK 21
+        uses: actions/setup-java@v4
+        with:
+          distribution: ${{ matrix.java-distribution }}
+          java-version: 21
+
+      - name: Cache Gradle packages
+        uses: actions/cache@v4
+        with:
+          path: |
+            ~/.gradle/caches
+            ~/.gradle/wrapper
+          key: gradle-${{ runner.os }}-${{ hashFiles('**/*.gradle*', '**/gradle-wrapper.properties') }}
+          restore-keys: gradle-${{ runner.os }}
+
+      - name: Install PCRE (Ubuntu)
+        if: ${{ matrix.os == 'ubuntu-latest' }}
+        run: sudo apt-get install -y libpcre2-8-0
+
+      - name: Build with Gradle (Ubuntu)
+        if: ${{ matrix.os == 'ubuntu-latest' }}
+        run: ./gradlew build -Dpcre2.library.path=/usr/lib/x86_64-linux-gnu
+
+      - name: Run tests (Ubuntu)
+        if: ${{ matrix.os == 'ubuntu-latest' }}
+        run: ./gradlew test -Dpcre2.library.path=/usr/lib/x86_64-linux-gnu

.gitignore

@@ -181,3 +181,25 @@ fabric.properties
 # virtual machine crash logs, see http://www.java.com/en/download/help/error_hotspot.xml
 hs_err_pid*
 replay_pid*
+## Origin: https://github.com/github/gitignore/blob/main/Gradle.gitignore
+.gradle
+**/build/
+!src/**/build/
+
+# Ignore Gradle GUI config
+gradle-app.setting
+
+# Avoid ignoring Gradle wrapper jar file (.jar files are usually ignored)
+!gradle-wrapper.jar
+
+# Avoid ignore Gradle wrappper properties
+!gradle-wrapper.properties
+
+# Cache of project
+.gradletasknamecache
+
+# Eclipse Gradle plugin generated files
+# Eclipse Core
+.project
+# JDT-specific (Eclipse Java Development Tools)
+.classpath

.vscode/settings.json

@@ -0,0 +1,3 @@
+{
+  "java.configuration.updateBuildConfiguration": "automatic"
+}

README.md

@@ -1,3 +1,62 @@
-# PCRE4J: [PCRE](https://www.pcre.org) for Java
+# PCRE4J: PCRE for Java
 
-The PCRE4J project is a Java wrapper for the [Perl Compatible Regular Expressions](https://github.com/PCRE2Project/pcre2) library.
+The PCRE4J project's goal is to bring the power of the [PCRE](https://www.pcre.org) library to Java.
+
+This project is brought to you by [Alexey Pelykh](https://github.com/alexey-pelykh) with a great gratitude to the PCRE
+library author [Philip Hazel](https://github.com/PhilipHazel) and its contributors.
+
+## Usage
+
+```java
+import org.pcre4j.Pcre2Code;
+import org.pcre4j.Pcre2CompileOption;
+import org.pcre4j.Pcre2MatchData;
+import org.pcre4j.Pcre2MatchOption;
+import org.pcre4j.Pcre4j;
+import org.pcre4j.Pcre4jUtils;
+// TODO: Select one of the following imports for the backend you want to use:
+import org.pcre4j.jna.Pcre2;
+// import org.pcre4j.ffm.Pcre2;
+
+public class Usage {
+    static {
+        Pcre4j.setup(new Pcre2());
+    }
+
+    public static String[] example(String pattern, String subject) {
+        final var code = new Pcre2Code(
+                pattern,
+                EnumSet.noneOf(Pcre2CompileOption.class),
+                null
+        );
+        final var matchData = new Pcre2MatchData(code);
+        code.match(
+                subject,
+                0,
+                EnumSet.noneOf(Pcre2MatchOption.class),
+                matchData,
+                null
+        );
+        return Pcre4jUtils.getMatchGroups(code, subject, matchData);
+    }
+}
+```
+
+## Backends
+
+The PCRE4J library supports several backends to invoke the `pcre2` API.
+
+### `jna`
+
+The `jna` backend uses the [Java Native Access](https://github.com/java-native-access/jna) library to invoke the `pcre2`
+shared library. For this backend to work, the `pcre2` shared library must be installed on the system and be visible to
+the JNA.
+
+### `ffm`
+
+The `ffm` backend uses the [Foreign Functions and Memory API](https://docs.oracle.com/en/java/javase/21/core/foreign-function-and-memory-api.html)
+to invoke the `pcre2` shared library. For this backend to work, the `pcre2` shared library must be installed on the
+system and be visible via `java.library.path`.
+
+Note that `--enable-preview` must be passed to the Java compiler to enable the preview features for this backend to be
+used.

api/build.gradle.kts

@@ -0,0 +1,83 @@
+/*
+ * Copyright (C) 2024 Oleksii PELYKH
+ *
+ * This file is a part of the PCRE4J. The PCRE4J is free software: you can redistribute it and/or modify it under the
+ * terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
+ * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License along with this program. If not, see
+ * <https://www.gnu.org/licenses/>.
+ */
+plugins {
+    `java-library`
+    `maven-publish`
+}
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    testImplementation("org.junit.jupiter:junit-jupiter:5.10.2")
+    testRuntimeOnly("org.junit.platform:junit-platform-launcher")
+}
+
+configurations {
+    implementation {
+        resolutionStrategy.failOnVersionConflict()
+    }
+}
+
+sourceSets {
+    main {
+        java.srcDir("src/main/java")
+    }
+}
+
+java {
+    sourceCompatibility = JavaVersion.VERSION_21
+    targetCompatibility = JavaVersion.VERSION_21
+
+    toolchain {
+        languageVersion = JavaLanguageVersion.of(21)
+    }
+
+    withSourcesJar()
+    withJavadocJar()
+}
+
+tasks.withType<Test> {
+    useJUnitPlatform()
+}
+
+tasks.named<Jar>("sourcesJar") {
+    duplicatesStrategy = DuplicatesStrategy.INCLUDE
+}
+
+publishing {
+    publications {
+        create<MavenPublication>("mavenJava") {
+            from(components["java"])
+
+            artifact(tasks.named("sourcesJar"))
+            artifact(tasks.named("javadocJar"))
+
+            groupId = "org.pcre4j"
+            artifactId = project.name
+            version = findProperty("pcre4j.version") as String? ?: "0.0.0-SNAPSHOT"
+        }
+    }
+
+    repositories {
+        mavenCentral {
+            credentials {
+                username = findProperty("pcre4j.mavenCentral.user") as String? ?: ""
+                password = findProperty("pcre4j.mavenCentral.password") as String? ?: ""
+            }
+        }
+    }
+}