/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef mozilla_image_decoders_EXIF_h

#define mozilla_image_decoders_EXIF_h

#include <stdint.h>

#include "nsDebug.h"

#include "Orientation.h"

namespace mozilla {

namespace image {

enum class ByteOrder : uint8_t {

  Unknown,

  LittleEndian,

  BigEndian

};

struct EXIFData

{

  EXIFData() { }

  explicit EXIFData(Orientation aOrientation) : orientation(aOrientation) { }

  const Orientation orientation;

};

class EXIFParser

{

public:

  static EXIFData

  Parse(const uint8_t* aData, const uint32_t aLength)

  {

    EXIFParser parser;

    return parser.ParseEXIF(aData, aLength);

  }

private:

  EXIFParser()

    : mStart(nullptr)

    , mCurrent(nullptr)

    , mLength(0)

    , mRemainingLength(0)

    , mByteOrder(ByteOrder::Unknown)

  { }

  EXIFData ParseEXIF(const uint8_t* aData, const uint32_t aLength);

  bool ParseEXIFHeader();

  bool ParseTIFFHeader(uint32_t& aIFD0OffsetOut);

  bool ParseIFD0(Orientation& aOrientationOut);

  bool ParseOrientation(uint16_t aType, uint32_t aCount, Orientation& aOut);

  bool Initialize(const uint8_t* aData, const uint32_t aLength);

  void Advance(const uint32_t aDistance);

  void JumpTo(const uint32_t aOffset);

  bool MatchString(const char* aString, const uint32_t aLength);

  bool MatchUInt16(const uint16_t aValue);

  bool ReadUInt16(uint16_t& aOut);

  bool ReadUInt32(uint32_t& aOut);

  const uint8_t* mStart;

  const uint8_t* mCurrent;

  uint32_t       mLength;

  uint32_t       mRemainingLength;

  ByteOrder      mByteOrder;

};

} // namespace image

} // namespace mozilla

#endif // mozilla_image_decoders_EXIF_h