(fix) lib: get compiled-widths and check for UTF-8

lib/src/main/java/org/pcre4j/Pcre2UtfWidth.java

@@ -0,0 +1,75 @@
+/*
+ * 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/>.
+ */
+package org.pcre4j;
+
+import org.pcre4j.api.IPcre2;
+
+import java.util.Arrays;
+import java.util.Optional;
+
+/**
+ * The UTF character width.
+ */
+public enum Pcre2UtfWidth {
+    /**
+     * UTF-8
+     */
+    UTF8(0b1),
+
+    /**
+     * UTF-16
+     */
+    UTF16(0b10),
+
+    /**
+     * UTF-32
+     */
+    UTF32(0b1000);
+
+    /**
+     * The integer value
+     */
+    private final int value;
+
+    /**
+     * Create an enum entry with the given integer value.
+     *
+     * @param value the integer value
+     */
+    private Pcre2UtfWidth(int value) {
+        this.value = value;
+    }
+
+    /**
+     * Get the enum entry by its integer value.
+     *
+     * @param value the integer value
+     * @return the enum entry
+     */
+    public static Optional<Pcre2UtfWidth> valueOf(int value) {
+        return Arrays.stream(values())
+                .filter(entry -> entry.value == value)
+                .findFirst();
+    }
+
+    /**
+     * Get the integer value.
+     *
+     * @return the integer value
+     */
+    public int value() {
+        return value;
+    }
+}

lib/src/main/java/org/pcre4j/Pcre4j.java

@@ -26,7 +26,7 @@ private Pcre4j() {
     }
 
     /**
-     * Setup the Pcre4j.
+     * Set up the PCRE4J library.
      *
      * @param api the API to use
      */
@@ -35,6 +35,11 @@ public static void setup(IPcre2 api) {
             throw new IllegalArgumentException("api must not be null");
         }
 
+        final var compiledWidths = Pcre4jUtils.getCompiledWidths(api);
+        if (!compiledWidths.contains(Pcre2UtfWidth.UTF8)) {
+            throw new IllegalArgumentException("api must support UTF-8, yet it only supports " + compiledWidths);
+        }
+
         synchronized (lock) {
             Pcre4j.api = api;
         }

lib/src/main/java/org/pcre4j/Pcre4jUtils.java

@@ -18,6 +18,7 @@
 
 import java.nio.ByteBuffer;
 import java.nio.charset.StandardCharsets;
+import java.util.EnumSet;
 import java.util.HashMap;
 import java.util.Map;
 
@@ -288,23 +289,34 @@ public static int getDefaultDepthLimit(IPcre2 api) {
     }
 
     /**
-     * Get which of the character width is compiled.
+     * Get which of the character widths the PCRE2 library was compiled with.
      *
      * @param api the PCRE2 API
      * @return the compiled character width (8, 16, or 32)
      */
-    public static int getCompiledWidth(IPcre2 api) {
+    public static EnumSet<Pcre2UtfWidth> getCompiledWidths(IPcre2 api) {
         if (api == null) {
             throw new IllegalArgumentException("api must not be null");
         }
 
-        final var width = new int[1];
-        final var result = api.config(IPcre2.CONFIG_COMPILED_WIDTHS, width);
+        final var widthsMask = new int[1];
+        final var result = api.config(IPcre2.CONFIG_COMPILED_WIDTHS, widthsMask);
         if (result < 0) {
             throw new IllegalStateException(getErrorMessage(api, result));
         }
 
-        return width[0];
+        final var widths = EnumSet.noneOf(Pcre2UtfWidth.class);
+        if ((widthsMask[0] & Pcre2UtfWidth.UTF8.value()) != 0) {
+            widths.add(Pcre2UtfWidth.UTF8);
+        }
+        if ((widthsMask[0] & Pcre2UtfWidth.UTF16.value()) != 0) {
+            widths.add(Pcre2UtfWidth.UTF16);
+        }
+        if ((widthsMask[0] & Pcre2UtfWidth.UTF32.value()) != 0) {
+            widths.add(Pcre2UtfWidth.UTF32);
+        }
+
+        return widths;
     }
 
     /**

test/src/main/java/org/pcre4j/test/Pcre2Tests.java

@@ -39,7 +39,7 @@ public void config() {
         Pcre4jUtils.isJitSupported(api);
         Pcre4jUtils.getDefaultHeapLimit(api);
         Pcre4jUtils.getDefaultDepthLimit(api);
-        Pcre4jUtils.getCompiledWidth(api);
+        Pcre4jUtils.getCompiledWidths(api);
         Pcre4jUtils.getDefaultBsr(api);
     }