From 0170ee36a9ef38352810f9f78d9f7a7f5a106e49 Mon Sep 17 00:00:00 2001
From: Harald Kuhr <harald.kuhr@gmail.com>
Date: Mon, 21 Aug 2017 22:03:18 +0200
Subject: [PATCH] Fix streamPos/bitPos issue in SubImageOutputStream.

---
 .../imageio/stream/SubImageOutputStream.java  | 26 ++++++++++++++++---
 1 file changed, 23 insertions(+), 3 deletions(-)

diff --git a/imageio/imageio-core/src/main/java/com/twelvemonkeys/imageio/stream/SubImageOutputStream.java b/imageio/imageio-core/src/main/java/com/twelvemonkeys/imageio/stream/SubImageOutputStream.java
index 2a24eef4..e72cde21 100644
--- a/imageio/imageio-core/src/main/java/com/twelvemonkeys/imageio/stream/SubImageOutputStream.java
+++ b/imageio/imageio-core/src/main/java/com/twelvemonkeys/imageio/stream/SubImageOutputStream.java
@@ -4,6 +4,8 @@ import javax.imageio.stream.ImageOutputStream;
 import javax.imageio.stream.ImageOutputStreamImpl;
 import java.io.IOException;
 
+import static com.twelvemonkeys.lang.Validate.notNull;
+
 /**
  * ImageInputStream that writes through a delegate, but keeps local position and bit offset.
  * Note: Flushing or closing this stream will *not* have an effect on the delegate.
@@ -14,29 +16,47 @@ import java.io.IOException;
  */
 public class SubImageOutputStream extends ImageOutputStreamImpl {
     private final ImageOutputStream stream;
+    private final long startPos;
 
-    public SubImageOutputStream(final ImageOutputStream stream) {
-        this.stream = stream;
+    public SubImageOutputStream(final ImageOutputStream stream) throws IOException {
+        this.stream = notNull(stream, "stream");
+        startPos = stream.getStreamPosition();
+    }
+
+    @Override
+    public void seek(long pos) throws IOException {
+        super.seek(pos);
+        stream.seek(startPos + pos);
     }
 
     @Override
     public void write(int b) throws IOException {
+        flushBits();
+
         stream.write(b);
+        streamPos++;
     }
 
     @Override
     public void write(byte[] b, int off, int len) throws IOException {
+        flushBits();
         stream.write(b, off, len);
+        streamPos += len;
     }
 
     @Override
     public int read() throws IOException {
+        bitOffset = 0;
+        streamPos++;
         return stream.read();
     }
 
     @Override
     public int read(byte[] b, int off, int len) throws IOException {
-        return stream.read(b, off, len);
+        bitOffset = 0;
+        int count = stream.read(b, off, len);
+        streamPos += count;
+        return count;
     }
 
     @Override