RetroZilla/modules/libpr0n/decoders/icon/nsIconDecoder.cpp

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 * 1.1 (the "License"); you may not use this file except in compliance with
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 * for the specific language governing rights and limitations under the
 * License.
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 * The Original Code is mozilla.org code.
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 * The Initial Developer of the Original Code is
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 * Portions created by the Initial Developer are Copyright (C) 2001
 * the Initial Developer. All Rights Reserved.
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 * Contributor(s):
 *   Scott MacGregor <mscott@netscape.com>
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#include "nsIconDecoder.h"
#include "nsIInputStream.h"
#include "imgIContainer.h"
#include "imgIContainerObserver.h"
#include "imgILoad.h"
#include "nspr.h"
#include "nsIComponentManager.h"
#include "nsRect.h"

NS_IMPL_THREADSAFE_ADDREF(nsIconDecoder)
NS_IMPL_THREADSAFE_RELEASE(nsIconDecoder)

NS_INTERFACE_MAP_BEGIN(nsIconDecoder)
   NS_INTERFACE_MAP_ENTRY(imgIDecoder)
NS_INTERFACE_MAP_END_THREADSAFE

nsIconDecoder::nsIconDecoder()
{
}

nsIconDecoder::~nsIconDecoder()
{ }


/** imgIDecoder methods **/

NS_IMETHODIMP nsIconDecoder::Init(imgILoad *aLoad)
{
  mObserver = do_QueryInterface(aLoad);  // we're holding 2 strong refs to the request.

  mImage = do_CreateInstance("@mozilla.org/image/container;1");
  if (!mImage) return NS_ERROR_OUT_OF_MEMORY;

  aLoad->SetImage(mImage);                                                   

  mFrame = do_CreateInstance("@mozilla.org/gfx/image/frame;2");
  if (!mFrame) return NS_ERROR_OUT_OF_MEMORY;

  return NS_OK;
}

NS_IMETHODIMP nsIconDecoder::Close()
{
  if (mObserver) 
  {
    mObserver->OnStopFrame(nsnull, mFrame);
    mObserver->OnStopContainer(nsnull, mImage);
    mObserver->OnStopDecode(nsnull, NS_OK, nsnull);
  }
  
  return NS_OK;
}

NS_IMETHODIMP nsIconDecoder::Flush()
{
  return NS_ERROR_NOT_IMPLEMENTED;
}

NS_IMETHODIMP nsIconDecoder::WriteFrom(nsIInputStream *inStr, PRUint32 count, PRUint32 *_retval)
{
  nsresult rv;

  PRUint8 * const buf = (PRUint8 *)PR_Malloc(count);
  if (!buf) return NS_ERROR_OUT_OF_MEMORY; /* we couldn't allocate the object */
 
  // read the data from the input stram...
  PRUint32 readLen;
  rv = inStr->Read((char*)buf, count, &readLen);
  NS_ENSURE_SUCCESS(rv, rv);
  NS_ENSURE_TRUE(readLen >= 3, NS_ERROR_UNEXPECTED); // w, h, alphaBits

  PRUint8 * const buf_end = buf + readLen;
  PRUint8 *data = buf;

  // since WriteFrom is only called once, go ahead and fire the on start notifications..

  mObserver->OnStartDecode(nsnull);
  // Read size
  PRInt32 w = *(data++);
  PRInt32 h = *(data++);
  PRUint8 alphaBits = *(data++);
  NS_ENSURE_TRUE(w > 0 && h > 0 && (alphaBits == 1 || alphaBits == 8),
                 NS_ERROR_UNEXPECTED);

  mImage->Init(w, h, mObserver);
  if (mObserver)
    mObserver->OnStartContainer(nsnull, mImage);

  gfx_format format = alphaBits == 1 ? gfx_format(gfxIFormats::RGB_A1)
                                     : gfx_format(gfxIFormats::RGB_A8);
  rv = mFrame->Init(0, 0, w, h, format, 24);
  if (NS_FAILED(rv))
    return rv;

  mImage->AppendFrame(mFrame);
  if (mObserver)
    mObserver->OnStartFrame(nsnull, mFrame);
  
  PRUint32 bpr, abpr;
  PRInt32 width, height;
  mFrame->GetImageBytesPerRow(&bpr);
  mFrame->GetAlphaBytesPerRow(&abpr);
  mFrame->GetWidth(&width);
  mFrame->GetHeight(&height);

  NS_ENSURE_TRUE(buf_end - data >= PRInt32(bpr + abpr) * height,
                 NS_ERROR_UNEXPECTED);
  
  PRInt32 rownum;
  for (rownum = 0; rownum < height; ++rownum, data += bpr)
    mFrame->SetImageData(data, bpr, rownum * bpr);

  for (rownum = 0; rownum < height; ++rownum, data += abpr)
    mFrame->SetAlphaData(data, abpr, rownum * abpr);   

  nsIntRect r(0, 0, width, height);
  mObserver->OnDataAvailable(nsnull, mFrame, &r);

  PR_Free(buf);

  return NS_OK;
}