#556 PICTImageReaderSpi no longer claim to decode known formats

imageio/imageio-pict/src/main/java/com/twelvemonkeys/imageio/plugins/pict/PICTImageReaderSpi.java

@@ -60,6 +60,13 @@ public final class PICTImageReaderSpi extends ImageReaderSpiBase {
         }
 
         ImageInputStream stream = (ImageInputStream) pSource;
+
+        // As PICT format don't have good magic and our method often gives false positives,
+        // so we'll need to check for other known formats (BMP, GIF, JPEG, PNG, PSD, TIFF) first
+        if (isOtherFormat(stream)) {
+            return false;
+        }
+
         stream.mark();
 
         try {
@@ -68,13 +75,12 @@ public final class PICTImageReaderSpi extends ImageReaderSpiBase {
                 return true;
             }
             else {
-                // Skip header 512 bytes for file-based streams
-                stream.reset();
-
-                // We need to set mark again, to make sure the reset call in
+                // We need to reset AND set mark again, to make sure the reset call in
                 // the finally block will not consume existing marks
+                stream.reset();
                 stream.mark();
 
+                // Skip header 512 bytes for file-based streams
                 skipNullHeader(stream);
             }
 
@@ -88,6 +94,60 @@ public final class PICTImageReaderSpi extends ImageReaderSpiBase {
         }
     }
 
+    // TODO: Candidate util method.
+    //      Might need to be able to exclude some formats
+    //      Might need to return the format matched...
+    static boolean isOtherFormat(final ImageInputStream stream) throws IOException {
+        stream.mark();
+
+        try {
+            byte[] signature = new byte[8];
+            stream.readFully(signature);
+
+            // BMP: off: 0, len: 2, magic: 'B', 'M'
+            // GIF: off: 0, len: 6, magic: 'G', 'I', 'F', '8', ('7' | '9'), 'a' (use only "GIF8"?)
+            // JPEG: off 0, len: 2, magic: 0xffd8 (SOI marker)
+            // PNG: off: 0, len: 8, magic: 0x89, 'P', 'N', 'G', 0x0d0a1a0a
+            // PSD: off: 0, len: 4, magic: '8', 'B', 'P', 'S'
+            // TIFF: off: 0, len: 4, magic: ('I', 'I', 0x00, (0x42 | 0x43)) | ('M', 'M', (0x42 | 0x43), 0x00) (43 is bigTiff)
+            if (signature[0] == 'B' && signature[1] == 'M') {
+                // BMP
+                return true;
+            }
+            if (signature[0] == 'G' && signature[1] == 'I' && signature[2] == 'F' && signature[3] == '8'
+                    && (signature[4] == '7' || signature[4] == '9') && signature[5] == 'a') {
+                // GIF
+                return true;
+            }
+            if (signature[0] == (byte) 0xFF && signature[1] == (byte) 0xD8 && signature[2] == (byte) 0xFF) {
+                // JPEG
+                return true;
+            }
+            if (signature[0] == (byte) 0x89 && signature[1] == 'P' && signature[2] == 'N' && signature[3] == 'G'
+                    && signature[4] == 0x0D && signature[5] == 0x0A && signature[6] == 0x1A && signature[7] == 0x0A) {
+                // PNG
+                return true;
+            }
+            if (signature[0] == '8' && signature[1] == 'B' && signature[2] == 'P' && signature[3] == 'S') {
+                // PSD
+                return true;
+            }
+            if ((signature[0] == 'I' && signature[1] == 'I' && (signature[2] == 42 ||  signature[2] == 43) && signature[3] == 0x00)
+                || signature[0] == 'M' && signature[1] == 'M' && signature[2] == 0x00 && (signature[3] == 42 ||  signature[3] == 43)) {
+                // TIFF/BigTIFF
+                return true;
+            }
+        }
+        catch (EOFException ignore) {
+            // Can't be any of the formats
+        }
+        finally {
+            stream.reset();
+        }
+
+        return false;
+    }
+
     static void skipNullHeader(final ImageInputStream pStream) throws IOException {
         // NOTE: Only skip if FILE FORMAT, not needed for Mac OS DnD
         // Spec says "platform dependent", may not be all nulls..
@@ -102,10 +162,6 @@ public final class PICTImageReaderSpi extends ImageReaderSpiBase {
         // Sanity check bounding box
         int y1 = pStream.readUnsignedShort();
         int x1 = pStream.readUnsignedShort();
-        // TODO: Figure out if frame can ever start at negative bounds...
-        // if (x1 != 0 || y1 != 0) {
-        //     return false;
-        // }
 
         int y2 = pStream.readUnsignedShort();
         int x2 = pStream.readUnsignedShort();

imageio/imageio-pict/src/test/java/com/twelvemonkeys/imageio/plugins/pict/PICTImageReaderTest.java

@@ -46,8 +46,8 @@ import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
+import static com.twelvemonkeys.imageio.plugins.pict.PICTImageReaderSpi.isOtherFormat;
+import static org.junit.Assert.*;
 
 /**
  * ICOImageReaderTestCase
@@ -116,6 +116,38 @@ public class PICTImageReaderTest extends ImageReaderAbstractTest<PICTImageReader
         return Arrays.asList("image/pict", "image/x-pict");
     }
 
+    @Test
+    public void testIsOtherFormat() throws IOException {
+        assertFalse(isOtherFormat(new ByteArrayImageInputStream(new byte[8])));
+
+        // BMP
+        assertTrue(isOtherFormat(new ByteArrayImageInputStream(new byte[] {'B', 'M', 0, 0, 0, 0, 0, 0})));
+
+        // GIF
+        assertTrue(isOtherFormat(new ByteArrayImageInputStream(new byte[] {'G', 'I', 'F', '8', '7', 'a', 0, 0})));
+        assertTrue(isOtherFormat(new ByteArrayImageInputStream(new byte[] {'G', 'I', 'F', '8', '9', 'a', 0, 0})));
+
+        // JPEG (JFIF, EXIF, "raw")
+        assertTrue(isOtherFormat(new ByteArrayImageInputStream(new byte[] {(byte) 0xFF, (byte) 0xD8, (byte) 0xFF, (byte) 0xE0, 0, 0, 0, 0})));
+        assertTrue(isOtherFormat(new ByteArrayImageInputStream(new byte[] {(byte) 0xFF, (byte) 0xD8, (byte) 0xFF, (byte) 0xE1, 0, 0, 0, 0})));
+        assertTrue(isOtherFormat(new ByteArrayImageInputStream(new byte[] {(byte) 0xFF, (byte) 0xD8, (byte) 0xFF, (byte) 0xDB, 0, 0, 0, 0})));
+        assertTrue(isOtherFormat(new ByteArrayImageInputStream(new byte[] {(byte) 0xFF, (byte) 0xD8, (byte) 0xFF, (byte) 0xC4, 0, 0, 0, 0})));
+
+        // PNG
+        assertTrue(isOtherFormat(new ByteArrayImageInputStream(new byte[] {(byte) 0x89, 'P', 'N', 'G', 0x0D, 0x0A, 0x1A, 0x0A})));
+
+        // PSD
+        assertTrue(isOtherFormat(new ByteArrayImageInputStream(new byte[] {'8', 'B', 'P', 'S', 0, 0, 0, 0})));
+
+        // TIFF (Little Endian, Big Endian)
+        assertTrue(isOtherFormat(new ByteArrayImageInputStream(new byte[] {'I', 'I', 42, 0, 0, 0, 0, 0})));
+        assertTrue(isOtherFormat(new ByteArrayImageInputStream(new byte[] {'M', 'M', 0, 42, 0, 0, 0, 0})));
+
+        // BigTIFF (Little Endian, Big Endian)
+        assertTrue(isOtherFormat(new ByteArrayImageInputStream(new byte[] {'I', 'I', 43, 0, 0, 0, 0, 0})));
+        assertTrue(isOtherFormat(new ByteArrayImageInputStream(new byte[] {'M', 'M', 0, 43, 0, 0, 0, 0})));
+    }
+
     @Ignore("Known issue")
     @Test
     @Override
@@ -148,6 +180,10 @@ public class PICTImageReaderTest extends ImageReaderAbstractTest<PICTImageReader
                 new TestData(getClassLoaderResource("/jpeg/R-7439-1151526181.jpeg"),
                 new Dimension(386, 396)
         )));
+        assertFalse(sProvider.canDecodeInput(
+                new TestData(getClassLoaderResource("/jpeg/89497426-adc19a00-d7ff-11ea-8ad1-0cbcd727b62a.jpeg"),
+                new Dimension(640, 480)
+        )));
     }
 
     @Test