The Tor Browser: image/decoders/EXIF.h@b8a032363ba2

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

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

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

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

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

     6 #ifndef MOZILLA_IMAGELIB_EXIF_H_

     7 #define MOZILLA_IMAGELIB_EXIF_H_

     9 #include <stdint.h>

    10 #include "mozilla/TypedEnum.h"

    11 #include "nsDebug.h"

    13 #include "Orientation.h"

    15 namespace mozilla {

    16 namespace image {

    18 MOZ_BEGIN_ENUM_CLASS(ByteOrder, uint8_t)

    19   Unknown,

    20   LittleEndian,

    21   BigEndian

    22 MOZ_END_ENUM_CLASS(ByteOrder)

    24 struct EXIFData

    25 {

    26   EXIFData() { }

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

    29   const Orientation orientation;

    30 };

    32 class EXIFParser

    33 {

    34 public:

    35   static EXIFData

    36   Parse(const uint8_t* aData, const uint32_t aLength)

    37   {

    38     EXIFParser parser;

    39     return parser.ParseEXIF(aData, aLength);

    40   }

    42 private:

    43   EXIFParser()

    44     : mStart(nullptr)

    45     , mCurrent(nullptr)

    46     , mLength(0)

    47     , mRemainingLength(0)

    48     , mByteOrder(ByteOrder::Unknown)

    49   { }

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

    52   bool ParseEXIFHeader();

    53   bool ParseTIFFHeader(uint32_t& aIFD0OffsetOut);

    54   bool ParseIFD0(Orientation& aOrientationOut);

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

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

    58   void Advance(const uint32_t aDistance);

    59   void JumpTo(const uint32_t aOffset);

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

    62   bool MatchUInt16(const uint16_t aValue);

    63   bool ReadUInt16(uint16_t& aOut);

    64   bool ReadUInt32(uint32_t& aOut);

    66   const uint8_t* mStart;

    67   const uint8_t* mCurrent;

    68   uint32_t       mLength;

    69   uint32_t       mRemainingLength;

    70   ByteOrder      mByteOrder;

    71 };

    73 }

    74 }

    76 #endif

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