TMI-JPEG: More lenient segment parsing, now allows 0xFF padding between segments + fixed an NPE in JPEGImageReader if the parsing fails.

imageio/imageio-metadata/src/main/java/com/twelvemonkeys/imageio/metadata/jpeg/JPEGSegmentUtil.java

@@ -153,11 +153,18 @@ public final class JPEGSegmentUtil {
         }
     }
 
-    static JPEGSegment readSegment(final ImageInputStream stream, Map<Integer, List<String>> segmentIdentifiers) throws IOException {
+    static JPEGSegment readSegment(final ImageInputStream stream, final Map<Integer, List<String>> segmentIdentifiers) throws IOException {
         int marker = stream.readUnsignedShort();
+
+        // Skip over 0xff padding between markers
+        while (marker == 0xffff) {
+            marker = (marker & 0xff) << 8 | stream.readUnsignedByte();
+        }
+
         if ((marker >> 8 & 0xff) != 0xff) {
             throw new IIOException(String.format("Bad marker: %04x", marker));
         }
+
         int length = stream.readUnsignedShort(); // Length including length field itself
 
         byte[] data;
@@ -196,7 +203,7 @@ public final class JPEGSegmentUtil {
         }
 
         @Override
-        public boolean contains(Object o) {
+        public boolean contains(final Object o) {
             return true;
         }
     }
@@ -208,13 +215,13 @@ public final class JPEGSegmentUtil {
         }
 
         @Override
-        public List<String> get(Object key) {
+        public List<String> get(final Object key) {
             return key instanceof Integer && JPEGSegment.isAppSegmentMarker((Integer) key) ? ALL_IDS : null;
 
         }
 
         @Override
-        public boolean containsKey(Object key) {
+        public boolean containsKey(final Object key) {
             return true;
         }
     }
@@ -226,7 +233,7 @@ public final class JPEGSegmentUtil {
         }
 
         @Override
-        public List<String> get(Object key) {
+        public List<String> get(final Object key) {
             return containsKey(key) ? ALL_IDS : null;
 
         }

imageio/imageio-metadata/src/test/java/com/twelvemonkeys/imageio/metadata/jpeg/JPEGSegmentUtilTest.java

@@ -196,4 +196,17 @@ public class JPEGSegmentUtilTest {
         assertEquals(JPEG.APP14, segments.get(21).marker());
         assertEquals("Adobe", segments.get(21).identifier());
     }
+
+    @Test
+    public void testReadPaddedSegments() throws IOException {
+        List<JPEGSegment> segments = JPEGSegmentUtil.readSegments(getData("/jpeg/jfif-padded-segments.jpg"), JPEGSegmentUtil.APP_SEGMENTS);
+        assertEquals(3, segments.size());
+
+        assertEquals(JPEG.APP0, segments.get(0).marker());
+        assertEquals("JFIF", segments.get(0).identifier());
+        assertEquals(JPEG.APP2, segments.get(1).marker());
+        assertEquals("ICC_PROFILE", segments.get(1).identifier());
+        assertEquals(JPEG.APP1, segments.get(2).marker());
+        assertEquals("Exif", segments.get(2).identifier());
+    }
 }