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