private static List <GfxImage> UnpackIco(byte[] pb)
{
if (pb == null)
{
Debug.Assert(false); return(null);
}
const int SizeICONDIR = 6;
const int SizeICONDIRENTRY = 16;
Debug.Assert(BitConverter.ToInt32(new byte[] { 1, 2, 3, 4 },
0) == 0x04030201); // Little-endian
if (pb.Length < SizeICONDIR)
{
return(null);
}
if (BitConverter.ToUInt16(pb, 0) != 0)
{
return(null); // Reserved, 0
}
if (BitConverter.ToUInt16(pb, 2) != 1)
{
return(null); // ICO type, 1
}
int n = BitConverter.ToUInt16(pb, 4);
if (n < 0)
{
Debug.Assert(false); return(null);
}
int cbDir = SizeICONDIR + (n * SizeICONDIRENTRY);
if (pb.Length < cbDir)
{
return(null);
}
List <GfxImage> l = new List <GfxImage>();
int iOffset = SizeICONDIR;
for (int i = 0; i < n; ++i)
{
int w = pb[iOffset];
int h = pb[iOffset + 1];
if ((w < 0) || (h < 0))
{
Debug.Assert(false); return(null);
}
int cb = BitConverter.ToInt32(pb, iOffset + 8);
if (cb <= 0)
{
return(null); // Data must have header (even BMP)
}
int p = BitConverter.ToInt32(pb, iOffset + 12);
if (p < cbDir)
{
return(null);
}
if ((p + cb) > pb.Length)
{
return(null);
}
try
{
byte[] pbImage = MemUtil.Mid <byte>(pb, p, cb);
GfxImage img = new GfxImage(pbImage, w, h);
l.Add(img);
}
catch (Exception) { Debug.Assert(false); return(null); }
iOffset += SizeICONDIRENTRY;
}
return(l);
}
private static Image ExtractBestImageFromIco(byte[] pb)
{
List <GfxImage> l = UnpackIco(pb);
if ((l == null) || (l.Count == 0))
{
return(null);
}
long qMax = 0;
foreach (GfxImage gi in l)
{
if (gi.Width == 0)
{
gi.Width = 256;
}
if (gi.Height == 0)
{
gi.Height = 256;
}
qMax = Math.Max(qMax, (long)gi.Width * (long)gi.Height);
}
byte[] pbHdrPng = new byte[] {
0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A
};
byte[] pbHdrJpeg = new byte[] { 0xFF, 0xD8, 0xFF };
Image imgBest = null;
int bppBest = -1;
foreach (GfxImage gi in l)
{
if (((long)gi.Width * (long)gi.Height) < qMax)
{
continue;
}
byte[] pbImg = gi.Data;
Image img = null;
try
{
if ((pbImg.Length > pbHdrPng.Length) &&
MemUtil.ArraysEqual(pbHdrPng,
MemUtil.Mid <byte>(pbImg, 0, pbHdrPng.Length)))
{
img = GfxUtil.LoadImage(pbImg);
}
else if ((pbImg.Length > pbHdrJpeg.Length) &&
MemUtil.ArraysEqual(pbHdrJpeg,
MemUtil.Mid <byte>(pbImg, 0, pbHdrJpeg.Length)))
{
img = GfxUtil.LoadImage(pbImg);
}
else
{
MemoryStream ms = new MemoryStream(pb, false);
try
{
Icon ico = new Icon(ms, gi.Width, gi.Height);
img = ico.ToBitmap();
ico.Dispose();
}
finally { ms.Close(); }
}
}
catch (Exception) { Debug.Assert(false); }
if (img == null)
{
continue;
}
if ((img.Width < gi.Width) || (img.Height < gi.Height))
{
Debug.Assert(false);
img.Dispose();
continue;
}
int bpp = GetBitsPerPixel(img.PixelFormat);
if (bpp > bppBest)
{
if (imgBest != null)
{
imgBest.Dispose();
}
imgBest = img;
bppBest = bpp;
}
else
{
img.Dispose();
}
}
return(imgBest);
}
