image/decoders/nsIconDecoder.cpp

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
   2  *
   3  * This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "nsIconDecoder.h"
   8 #include "nsIInputStream.h"
   9 #include "nspr.h"
  10 #include "nsRect.h"
  11 #include "nsError.h"
  12 #include "RasterImage.h"
  13 #include <algorithm>
  14
  15 namespace mozilla {
  16 namespace image {
  17
  18 nsIconDecoder::nsIconDecoder(RasterImage* aImage)
  19  : Decoder(aImage),
  20    mWidth(-1),
  21    mHeight(-1),
  22    mPixBytesRead(0),
  23    mState(iconStateStart)
  24 {
  25   // Nothing to do
  26 }
  27
  28 nsIconDecoder::~nsIconDecoder()
  29 { }
  30
  31 void
  32 nsIconDecoder::WriteInternal(const char* aBuffer, uint32_t aCount)
  33 {
  34   NS_ABORT_IF_FALSE(!HasError(), "Shouldn't call WriteInternal after error!");
  35
  36   // We put this here to avoid errors about crossing initialization with case
  37   // jumps on linux.
  38   uint32_t bytesToRead = 0;
  39
  40   // Loop until the input data is gone
  41   while (aCount > 0) {
  42     switch (mState) {
  43       case iconStateStart:
  44
  45         // Grab the width
  46         mWidth = (uint8_t)*aBuffer;
  47
  48         // Book Keeping
  49         aBuffer++;
  50         aCount--;
  51         mState = iconStateHaveHeight;
  52         break;
  53
  54       case iconStateHaveHeight:
  55
  56         // Grab the Height
  57         mHeight = (uint8_t)*aBuffer;
  58
  59         // Post our size to the superclass
  60         PostSize(mWidth, mHeight);
  61
  62         PostHasTransparency();
  63
  64         if (HasError()) {
  65           // Setting the size led to an error.
  66           mState = iconStateFinished;
  67           return;
  68         }
  69
  70         // If We're doing a size decode, we're done
  71         if (IsSizeDecode()) {
  72           mState = iconStateFinished;
  73           break;
  74         }
  75
  76         if (!mImageData) {
  77           PostDecoderError(NS_ERROR_OUT_OF_MEMORY);
  78           return;
  79         }
  80
  81         // Book Keeping
  82         aBuffer++;
  83         aCount--;
  84         mState = iconStateReadPixels;
  85         break;
  86
  87       case iconStateReadPixels: {
  88
  89         // How many bytes are we reading?
  90         bytesToRead = std::min(aCount, mImageDataLength - mPixBytesRead);
  91
  92         // Copy the bytes
  93         memcpy(mImageData + mPixBytesRead, aBuffer, bytesToRead);
  94
  95         // Performance isn't critical here, so our update rectangle is
  96         // always the full icon
  97         nsIntRect r(0, 0, mWidth, mHeight);
  98
  99         // Invalidate
 100         PostInvalidation(r);
 101
 102         // Book Keeping
 103         aBuffer += bytesToRead;
 104         aCount -= bytesToRead;
 105         mPixBytesRead += bytesToRead;
 106
 107         // If we've got all the pixel bytes, we're finished
 108         if (mPixBytesRead == mImageDataLength) {
 109           PostFrameStop();
 110           PostDecodeDone();
 111           mState = iconStateFinished;
 112         }
 113         break;
 114       }
 115
 116       case iconStateFinished:
 117
 118         // Consume all excess data silently
 119         aCount = 0;
 120
 121         break;
 122     }
 123   }
 124 }
 125
 126 } // namespace image
 127 } // namespace mozilla