76 lines
1.8 KiB
C++
76 lines
1.8 KiB
C++
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef mozilla_image_decoders_EXIF_h
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#define mozilla_image_decoders_EXIF_h
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#include <stdint.h>
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#include "nsDebug.h"
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#include "Orientation.h"
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namespace mozilla {
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namespace image {
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enum class ByteOrder : uint8_t {
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Unknown,
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LittleEndian,
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BigEndian
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};
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struct EXIFData
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{
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EXIFData() { }
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explicit EXIFData(Orientation aOrientation) : orientation(aOrientation) { }
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const Orientation orientation;
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};
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class EXIFParser
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{
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public:
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static EXIFData
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Parse(const uint8_t* aData, const uint32_t aLength)
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{
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EXIFParser parser;
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return parser.ParseEXIF(aData, aLength);
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}
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private:
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EXIFParser()
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: mStart(nullptr)
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, mCurrent(nullptr)
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, mLength(0)
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, mRemainingLength(0)
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, mByteOrder(ByteOrder::Unknown)
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{ }
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EXIFData ParseEXIF(const uint8_t* aData, const uint32_t aLength);
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bool ParseEXIFHeader();
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bool ParseTIFFHeader(uint32_t& aIFD0OffsetOut);
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bool ParseIFD0(Orientation& aOrientationOut);
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bool ParseOrientation(uint16_t aType, uint32_t aCount, Orientation& aOut);
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bool Initialize(const uint8_t* aData, const uint32_t aLength);
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void Advance(const uint32_t aDistance);
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void JumpTo(const uint32_t aOffset);
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bool MatchString(const char* aString, const uint32_t aLength);
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bool MatchUInt16(const uint16_t aValue);
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bool ReadUInt16(uint16_t& aOut);
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bool ReadUInt32(uint32_t& aOut);
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const uint8_t* mStart;
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const uint8_t* mCurrent;
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uint32_t mLength;
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uint32_t mRemainingLength;
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ByteOrder mByteOrder;
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};
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} // namespace image
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} // namespace mozilla
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#endif // mozilla_image_decoders_EXIF_h
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