box.h

// Copyright 2014 Google LLC. All rights reserved.
//
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file or at
// https://developers.google.com/open-source/licenses/bsd
 
#ifndef PACKAGER_MEDIA_FORMATS_MP4_BOX_H_
#define PACKAGER_MEDIA_FORMATS_MP4_BOX_H_
 
#include <cstddef>
#include <cstdint>
 
#include <packager/media/base/fourccs.h>
 
namespace shaka {
namespace media {
 
class BufferWriter;
 
namespace mp4 {
 
class BoxBuffer;
class BoxReader;
 
struct Box {
 public:
  Box();
  virtual ~Box();
  bool Parse(BoxReader* reader);
  void Write(BufferWriter* writer);
  void WriteHeader(BufferWriter* writer);
  uint32_t ComputeSize();
  virtual uint32_t HeaderSize() const;
  virtual FourCC BoxType() const = 0;
 
  //          function expects that ComputeSize has been invoked already.
  uint32_t box_size() { return box_size_; }
 
 protected:
  virtual bool ReadWriteHeaderInternal(BoxBuffer* buffer);
 
 private:
  friend class BoxBuffer;
  // Read/write the mp4 box from/to BoxBuffer. Note that this function expects
  // that ComputeSize has been invoked already.
  virtual bool ReadWriteInternal(BoxBuffer* buffer) = 0;
  // Compute the size of this box. A value of 0 should be returned if the box
  // should not be written. Note that this function won't update box size.
  virtual size_t ComputeSizeInternal() = 0;
 
  // We don't support 64-bit box sizes. 32-bit should be large enough for our
  // current needs.
  uint32_t box_size_;
 
  // Not using DISALLOW_COPY_AND_ASSIGN here intentionally to allow the compiler
  // generated copy constructor and assignment operator.
};
 
struct FullBox : Box {
 public:
  FullBox();
  ~FullBox() override;
 
  uint32_t HeaderSize() const final;
 
  uint8_t version = 0;
  uint32_t flags = 0;
 
 protected:
  bool ReadWriteHeaderInternal(BoxBuffer* buffer) final;
 
  // Not using DISALLOW_COPY_AND_ASSIGN here intentionally to allow the compiler
  // generated copy constructor and assignment operator.
};
 
}  // namespace mp4
}  // namespace media
}  // namespace shaka
 
#endif  // PACKAGER_MEDIA_FORMATS_MP4_BOX_H_