gecko/image/decoders/nsIconDecoder.cpp
2012-05-21 12:12:37 +01:00

135 lines
3.2 KiB
C++

/* -*- 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/. */
#include "nsIconDecoder.h"
#include "nsIInputStream.h"
#include "RasterImage.h"
#include "imgIContainerObserver.h"
#include "nspr.h"
#include "nsRect.h"
#include "ImageErrors.h"
namespace mozilla {
namespace image {
nsIconDecoder::nsIconDecoder(RasterImage &aImage, imgIDecoderObserver* aObserver)
: Decoder(aImage, aObserver),
mWidth(-1),
mHeight(-1),
mPixBytesRead(0),
mPixBytesTotal(0),
mImageData(nsnull),
mState(iconStateStart)
{
// Nothing to do
}
nsIconDecoder::~nsIconDecoder()
{ }
void
nsIconDecoder::WriteInternal(const char *aBuffer, PRUint32 aCount)
{
NS_ABORT_IF_FALSE(!HasError(), "Shouldn't call WriteInternal after error!");
// We put this here to avoid errors about crossing initialization with case
// jumps on linux.
PRUint32 bytesToRead = 0;
nsresult rv;
// Performance isn't critical here, so our update rectangle is
// always the full icon
nsIntRect r(0, 0, mWidth, mHeight);
// Loop until the input data is gone
while (aCount > 0) {
switch (mState) {
case iconStateStart:
// Grab the width
mWidth = (PRUint8)*aBuffer;
// Book Keeping
aBuffer++;
aCount--;
mState = iconStateHaveHeight;
break;
case iconStateHaveHeight:
// Grab the Height
mHeight = (PRUint8)*aBuffer;
// Post our size to the superclass
PostSize(mWidth, mHeight);
if (HasError()) {
// Setting the size led to an error.
mState = iconStateFinished;
return;
}
// If We're doing a size decode, we're done
if (IsSizeDecode()) {
mState = iconStateFinished;
break;
}
// Add the frame and signal
rv = mImage.EnsureFrame(0, 0, 0, mWidth, mHeight,
gfxASurface::ImageFormatARGB32,
&mImageData, &mPixBytesTotal);
if (NS_FAILED(rv)) {
PostDecoderError(rv);
return;
}
// Tell the superclass we're starting a frame
PostFrameStart();
// Book Keeping
aBuffer++;
aCount--;
mState = iconStateReadPixels;
break;
case iconStateReadPixels:
// How many bytes are we reading?
bytesToRead = NS_MIN(aCount, mPixBytesTotal - mPixBytesRead);
// Copy the bytes
memcpy(mImageData + mPixBytesRead, aBuffer, bytesToRead);
// Invalidate
PostInvalidation(r);
// Book Keeping
aBuffer += bytesToRead;
aCount -= bytesToRead;
mPixBytesRead += bytesToRead;
// If we've got all the pixel bytes, we're finished
if (mPixBytesRead == mPixBytesTotal) {
PostFrameStop();
PostDecodeDone();
mState = iconStateFinished;
}
break;
case iconStateFinished:
// Consume all excess data silently
aCount = 0;
break;
}
}
}
} // namespace image
} // namespace mozilla