gecko-dev/image/decoders/nsJPEGDecoder.h

/* -*- 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_nsJPEGDecoder_h
#define mozilla_image_decoders_nsJPEGDecoder_h

#include "RasterImage.h"
// On Windows systems, RasterImage.h brings in 'windows.h', which defines INT32.
// But the jpeg decoder has its own definition of INT32. To avoid build issues,
// we need to undefine the version from 'windows.h'.
#undef INT32

#include "Decoder.h"

#include "nsIInputStream.h"
#include "nsIPipe.h"
#include "qcms.h"

extern "C" {
#include "jpeglib.h"
}

#include <setjmp.h>

namespace mozilla {
namespace image {

typedef struct {
    struct jpeg_error_mgr pub;  // "public" fields for IJG library
    jmp_buf setjmp_buffer;      // For handling catastropic errors
} decoder_error_mgr;

typedef enum {
    JPEG_HEADER,                          // Reading JFIF headers
    JPEG_START_DECOMPRESS,
    JPEG_DECOMPRESS_PROGRESSIVE,          // Output progressive pixels
    JPEG_DECOMPRESS_SEQUENTIAL,           // Output sequential pixels
    JPEG_DONE,
    JPEG_SINK_NON_JPEG_TRAILER,          // Some image files have a
                                         // non-JPEG trailer
    JPEG_ERROR
} jstate;

class RasterImage;
struct Orientation;

class nsJPEGDecoder : public Decoder
{
public:
  virtual ~nsJPEGDecoder();

  virtual void SetSampleSize(int aSampleSize) override
  {
    mSampleSize = aSampleSize;
  }

  virtual void InitInternal() override;
  virtual void WriteInternal(const char* aBuffer, uint32_t aCount) override;
  virtual void FinishInternal() override;

  virtual Telemetry::ID SpeedHistogram() override;
  void NotifyDone();

protected:
  Orientation ReadOrientationFromEXIF();
  void OutputScanlines(bool* suspend);

private:
  friend class DecoderFactory;

  // Decoders should only be instantiated via DecoderFactory.
  nsJPEGDecoder(RasterImage* aImage, Decoder::DecodeStyle aDecodeStyle);

public:
  struct jpeg_decompress_struct mInfo;
  struct jpeg_source_mgr mSourceMgr;
  decoder_error_mgr mErr;
  jstate mState;

  uint32_t mBytesToSkip;

  const JOCTET* mSegment;   // The current segment we are decoding from
  uint32_t mSegmentLen;     // amount of data in mSegment

  JOCTET* mBackBuffer;
  uint32_t mBackBufferLen; // Offset of end of active backtrack data
  uint32_t mBackBufferSize; // size in bytes what mBackBuffer was created with
  uint32_t mBackBufferUnreadLen; // amount of data currently in mBackBuffer

  JOCTET * mProfile;
  uint32_t mProfileLength;

  qcms_profile* mInProfile;
  qcms_transform* mTransform;

  bool mReading;

  const Decoder::DecodeStyle mDecodeStyle;

  uint32_t mCMSMode;

  int mSampleSize;
};

} // namespace image
} // namespace mozilla

#endif // mozilla_image_decoders_nsJPEGDecoder_h