/// <summary>Read a single image into a byte array.</summary>
byte[] read(int i)
{
ICONDIRECTORY dir = m_images[i];
if (stream.CanSeek)
{
stream.Seek(dir.imageOffset, SeekOrigin.Begin);
}
else
{
if (streamPosition > dir.imageOffset)
{
throw new ArgumentException("The stream is forward-only, can't rewind it");
}
int skipBytes = dir.imageOffset - streamPosition;
stream.skip(skipBytes);
streamPosition += skipBytes;
}
int cb = dir.sizeInBytes;
byte[] result = new byte[cb];
if (cb != stream.Read(result, 0, cb))
{
throw new EndOfStreamException();
}
if (!stream.CanSeek)
{
streamPosition += cb;
}
return(result);
}
internal ImageFormat(ref ICONDIRECTORY icd, uint bmp)
{
size = icd.size;
colorsCount = icd.colorsCount;
planes = icd.planes;
bitCount = icd.bitCount;
switch (bmp)
{
case 40:
format = eFormat.Bitmap;
break;
case PngSignature:
format = eFormat.PNG;
break;
default:
throw new ArgumentException("The image format is not supported");
}
}
/// <summary>Read file header and directory</summary>
public CursorFile(Stream stream, bool leaveOpen = false)
{
Debug.Assert(6 == Marshal.SizeOf <ICONDIR>());
ICONDIR header = new ICONDIR();
stream.Read(MiscUtils.asSpan(ref header));
if (header.idReserved != 0)
{
throw new ArgumentException("The stream is not a valid cursor file");
}
if (header.idType != eImageType.Cursor)
{
if (header.idType == eImageType.Icon)
{
throw new ArgumentException("The stream contains an icon, not a cursor");
}
throw new ArgumentException("The stream is not a valid cursor file");
}
if (header.idCount <= 0)
{
throw new ArgumentException("The stream doesn't have any images");
}
Debug.Assert(16 == Marshal.SizeOf <ICONDIRECTORY>());
m_images = new ICONDIRECTORY[header.idCount];
stream.read(m_images);
this.stream = stream;
this.leaveOpen = leaveOpen;
if (!stream.CanSeek)
{
streamPosition = Marshal.SizeOf <ICONDIR>() + Marshal.SizeOf <ICONDIRECTORY>() * m_images.Length;
}
}
static ulong headerValues(ref ICONDIRECTORY icd)
{
var bytes = MiscUtils.asSpan(ref icd).Slice(0, 8);
return(MemoryMarshal.Cast <byte, ulong>(bytes)[0]);
}
internal ImageInfo(ICONDIRECTORY idi)
{
size = idi.size;
hotspot = idi.hotspot;
colorsCount = idi.colorsCount;
}
