gecko-dev/image/decoders/nsIconDecoder.cpp

128 строки
2.9 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 "nspr.h"
#include "nsRect.h"
#include "nsError.h"
#include "RasterImage.h"
#include <algorithm>
namespace mozilla {
namespace image {
nsIconDecoder::nsIconDecoder(RasterImage* aImage)
: Decoder(aImage),
mWidth(-1),
mHeight(-1),
mPixBytesRead(0),
mState(iconStateStart)
{
// Nothing to do
}
nsIconDecoder::~nsIconDecoder()
{ }
void
nsIconDecoder::WriteInternal(const char* aBuffer, uint32_t aCount)
{
MOZ_ASSERT(!HasError(), "Shouldn't call WriteInternal after error!");
// We put this here to avoid errors about crossing initialization with case
// jumps on linux.
uint32_t bytesToRead = 0;
// Loop until the input data is gone
while (aCount > 0) {
switch (mState) {
case iconStateStart:
// Grab the width
mWidth = (uint8_t)*aBuffer;
// Book Keeping
aBuffer++;
aCount--;
mState = iconStateHaveHeight;
break;
case iconStateHaveHeight:
// Grab the Height
mHeight = (uint8_t)*aBuffer;
// Post our size to the superclass
PostSize(mWidth, mHeight);
PostHasTransparency();
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;
}
if (!mImageData) {
PostDecoderError(NS_ERROR_OUT_OF_MEMORY);
return;
}
// Book Keeping
aBuffer++;
aCount--;
mState = iconStateReadPixels;
break;
case iconStateReadPixels: {
// How many bytes are we reading?
bytesToRead = std::min(aCount, mImageDataLength - mPixBytesRead);
// Copy the bytes
memcpy(mImageData + mPixBytesRead, aBuffer, bytesToRead);
// Performance isn't critical here, so our update rectangle is
// always the full icon
nsIntRect r(0, 0, mWidth, mHeight);
// Invalidate
PostInvalidation(r);
// Book Keeping
aBuffer += bytesToRead;
aCount -= bytesToRead;
mPixBytesRead += bytesToRead;
// If we've got all the pixel bytes, we're finished
if (mPixBytesRead == mImageDataLength) {
PostFrameStop();
PostDecodeDone();
mState = iconStateFinished;
}
break;
}
case iconStateFinished:
// Consume all excess data silently
aCount = 0;
break;
}
}
}
} // namespace image
} // namespace mozilla