Set error on unrecognized top-level BMFF boxes.

media/mp4/box_reader.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MEDIA_MP4_BOX_READER_H_
 #define MEDIA_MP4_BOX_READER_H_
 
 #include <map>
 #include <vector>
 
@@ skipping 73 matching lines @@
   // does not check to ensure the entire box is in the buffer before returning
   // true. The semantics of |*err| are the same as above.
   //
   // |buf| is not retained.
   static bool StartTopLevelBox(const uint8* buf,
                                const int buf_size,
                                FourCC* type,
                                int* box_size,
                                bool* err) WARN_UNUSED_RESULT;
 
+  // Returns true if |type| is recognized to be a top-level box, false
+  // otherwise. This returns true for some boxes which we do not parse.
+  // Helpful in debugging misaligned appends.
+  static bool IsValidTopLevelBox(const FourCC& type);
+
   // Scan through all boxes within the current box, starting at the current
   // buffer position. Must be called before any of the *Child functions work.
   bool ScanChildren() WARN_UNUSED_RESULT;
 
   // Read exactly one child box from the set of children. The type of the child
   // will be determined by the BoxType() method of |child|.
   bool ReadChild(Box* child) WARN_UNUSED_RESULT;
 
   // Read one child if available. Returns false on error, true on successful
   // read or on child absent.
@@ skipping 88 matching lines @@
     ++child_itr;
   }
   children_.clear();
   return true;
 }
 
 }  // namespace mp4
 }  // namespace media
 
 #endif  // MEDIA_MP4_BOX_READER_H_