1 files changed, 75 insertions, 0 deletions
diff --git a/image/decoders/EXIF.h b/image/decoders/EXIF.h
new file mode 100644
index 000000000..9028f2cf8
--- /dev/null
+++ b/image/decoders/EXIF.h
@@ -0,0 +1,75 @@
+/* -*- 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