fix: ArrayIndexOutOfBoundsException with multiple bytes for a character #32

src/main/java/com/github/f4b6a3/ulid/Ulid.java

@@ -793,6 +793,16 @@ public final class Ulid implements Serializable, Comparable<Ulid> {
 			return false; // null or wrong size!
 		}
 
+		for (int i = 0; i < chars.length; i++) {
+			try {
+				if (ALPHABET_VALUES[chars[i]] == -1) {
+					return false; // invalid character!
+				}
+			} catch (ArrayIndexOutOfBoundsException e) {
+				return false; // Multibyte character!
+			}
+		}
+
 		// The time component has 48 bits.
 		// The base32 encoded time component has 50 bits.
 		// The time component cannot be greater than than 2^48-1.
@@ -805,12 +815,6 @@ public final class Ulid implements Serializable, Comparable<Ulid> {
 			return false; // time overflow!
 		}
 
-		for (int i = 0; i < chars.length; i++) {
-			if (ALPHABET_VALUES[chars[i]] == -1) {
-				return false; // invalid character!
-			}
-		}
-
 		return true; // It seems to be OK.
 	}
 }

src/test/java/com/github/f4b6a3/ulid/UlidTest.java

@@ -104,7 +104,7 @@ public class UlidTest extends UlidFactoryTest {
 	}
 
 	@Test
-	public void testFromStrings() {
+	public void testFromString() {
 		Random random = new Random();
 		for (int i = 0; i < DEFAULT_LOOP_MAX; i++) {
 			final long msb = random.nextLong();
@@ -610,6 +610,16 @@ public class UlidTest extends UlidFactoryTest {
 		} catch (IllegalArgumentException e) {
 			// success
 		}
+
+		// https://github.com/f4b6a3/ulid-creator/issues/32
+		// https://www.compart.com/en/unicode/U+3617 (㘗: whisper; to whistle)
+		ulid = "0123456789ABCDEFGHJKMNPQR\u3617";
+		try {
+			Ulid.toCharArray(ulid);
+			fail("Should throw an exception");
+		} catch (IllegalArgumentException e) {
+			// success
+		}
 	}
 
 	@Test