5043343: FileImageInputStream and FileImageOutputStream do not properly track streamPos for RandomAccessFile

Reviewed-by: prr

src/java.desktop/share/classes/javax/imageio/stream/FileImageInputStream.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2000, 2024, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2000, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -89,6 +89,10 @@ public class FileImageInputStream extends ImageInputStreamImpl {
             throw new IllegalArgumentException("raf == null!");
         }
         this.raf = raf;
+        try {
+            this.streamPos = raf.getFilePointer();
+        } catch (IOException ignored) {
+        }
 
         disposerRecord = new CloseableDisposerRecord(raf);
         if (getClass() == FileImageInputStream.class) {

src/java.desktop/share/classes/javax/imageio/stream/FileImageOutputStream.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2000, 2024, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2000, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -81,6 +81,10 @@ public class FileImageOutputStream extends ImageOutputStreamImpl {
             throw new IllegalArgumentException("raf == null!");
         }
         this.raf = raf;
+        try {
+            this.streamPos = raf.getFilePointer();
+        } catch (IOException ignored) {
+        }
 
         disposerRecord = new CloseableDisposerRecord(raf);
         if (getClass() == FileImageOutputStream.class) {

test/jdk/javax/imageio/stream/FileImageStreamPos.java

@@ -0,0 +1,102 @@
+/*
+ * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code 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 General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @bug 5043343
+ * @summary Verify that FIIS and FIOS constructors set streamPos to RAF position
+ * @library /test/lib
+ * @build jdk.test.lib.RandomFactory
+ * @run main FileImageStreamPos
+ * @key randomness
+ */
+
+import java.awt.image.BufferedImage;
+import java.io.File;
+import java.io.IOException;
+import java.io.RandomAccessFile;
+import java.util.Arrays;
+import java.util.Random;
+import javax.imageio.ImageIO;
+import javax.imageio.stream.FileImageInputStream;
+import javax.imageio.stream.FileImageOutputStream;
+import jdk.test.lib.RandomFactory;
+
+public class FileImageStreamPos {
+    // Maximum size of random prefix
+    private static final int BOUND = 1024;
+
+    // Maximum image dimensions
+    public static final int SIZE_MIN = 512;
+    public static final int SIZE_MAX = 1024;
+
+    public static void main(String[] args) throws IOException {
+
+        // Create source image with random content
+        Random random = RandomFactory.getRandom();
+        final int w = random.nextInt(SIZE_MIN, SIZE_MAX);
+        final int h = random.nextInt(SIZE_MIN, SIZE_MAX);
+        BufferedImage srcImage =
+            new BufferedImage(w, h, BufferedImage.TYPE_3BYTE_BGR);
+        int[] rgbArray = random.ints(w*h).toArray();
+        srcImage.setRGB(0, 0, w, h, rgbArray, 0, w);
+
+        // Write some random bytes followed by the image
+        File dstFile = File.createTempFile("before", "after", new File("."));
+        dstFile.deleteOnExit();
+        final int offset = random.nextInt(BOUND);
+        System.out.println("offset: " + offset);
+        try(RandomAccessFile raf = new RandomAccessFile(dstFile, "rw");) {
+            byte[] b = new byte[offset];
+            random.nextBytes(b);
+            raf.write(b);
+            FileImageOutputStream fios = new FileImageOutputStream(raf);
+            if (fios.getStreamPosition() != offset)
+                throw new RuntimeException(fios.getStreamPosition() + " != " +
+                                           offset);
+            ImageIO.write(srcImage, "PNG", fios);
+        }
+
+        // Read the image just written and compare with the original
+        try(RandomAccessFile raf = new RandomAccessFile(dstFile, "r")) {
+            // Read the image from after then random prefix
+            raf.skipBytes(offset);
+            FileImageInputStream fiis = new FileImageInputStream(raf);
+            if (fiis.getStreamPosition() != offset)
+                throw new RuntimeException(fiis.getStreamPosition() + " != " +
+                                           offset);
+            BufferedImage dstImage = ImageIO.read(fiis);
+
+            // Compare the image dimensions
+            if (dstImage.getWidth() != w)
+                throw new RuntimeException(dstImage.getWidth() + " != " + w);
+            if (dstImage.getHeight() != h)
+                throw new RuntimeException(dstImage.getHeight() + " != " + h);
+
+            // Compare RGB pixels
+            if (!Arrays.equals(srcImage.getRGB(0, 0, w, h, null, 0, w),
+                               dstImage.getRGB(0, 0, w, h, null, 0, w)))
+                throw new RuntimeException("Pixels are not equal");
+        }
+    }
+}