7014528: ColorModel and SampleModel gotten from the same ImageTypeSpecifier...

7014528: ColorModel and SampleModel gotten from the same ImageTypeSpecifier instance can be not compatible
Reviewed-by: jgodinez, prr

src/share/classes/java/awt/image/PackedColorModel.java

@@ -343,8 +343,13 @@ public abstract class PackedColorModel extends ColorModel {
         if (bitMasks.length != maskArray.length) {
             return false;
         }
+
+        /* compare 'effective' masks only, i.e. only part of the mask
+         * which fits the capacity of the transfer type.
+         */
+        int maxMask = (int)((1L << DataBuffer.getDataTypeSize(transferType)) - 1);
         for (int i=0; i < bitMasks.length; i++) {
-            if (bitMasks[i] != maskArray[i]) {
+            if ((maxMask & bitMasks[i]) != (maxMask & maskArray[i])) {
                 return false;
             }
         }