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Use generic Marshal.SizeOf.

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This commit is contained in:
Eugene Wang
2025-11-12 01:38:30 -05:00
parent 8afc52c82b
commit ca17510f18
2 changed files with 129 additions and 129 deletions
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2
src/NTwain/Native/BITMAP.cs
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@@ -34,7 +34,7 @@ namespace Windows.Win32.Graphics.Gdi
/// <returns></returns>
public static uint GetByteSize()
{
return (uint)Marshal.SizeOf(typeof(BITMAPINFOHEADER));
return (uint)Marshal.SizeOf<BITMAPINFOHEADER>();
}
/// <summary>
/// Checks to see if this structure contain valid data.

256
src/NTwain/Native/ImageTools.cs
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@@ -5,142 +5,142 @@ using Windows.Win32.Graphics.Gdi;
namespace NTwain.Native
{
static class ImageTools
{
// this is modified from twain cs sample
// http://sourceforge.net/projects/twainforcsharp/?source=typ_redirect
public static bool IsDib(IntPtr data)
static class ImageTools
{
// a quick check not guaranteed correct,
// compare first 2 bytes to size of struct (which is also the first field)
var test = Marshal.ReadInt16(data);
// should be 40
return test == BITMAPINFOHEADER.GetByteSize();
}
public static bool IsTiff(IntPtr data)
{
var test = Marshal.ReadInt16(data);
// should be II
return test == 0x4949;
}
// this is modified from twain cs sample
// http://sourceforge.net/projects/twainforcsharp/?source=typ_redirect
public static unsafe BufferedData? GetBitmapData(IntPtr data)
{
var infoHeader = Marshal.PtrToStructure<BITMAPINFOHEADER>(data);
if (infoHeader.Validate())
{
var fileHeaderSize = Marshal.SizeOf(typeof(BITMAPFILEHEADER));
var fileHeader = new BITMAPFILEHEADER
public static bool IsDib(IntPtr data)
{
bfType = 0x4D42, // "BM"
bfOffBits = (uint)fileHeaderSize +
infoHeader.biSize +
(infoHeader.biClrUsed * 4)
};
fileHeader.bfSize = fileHeader.bfOffBits + infoHeader.biSizeImage;
var dataCopy = BufferedData.MemPool.Rent((int)fileHeader.bfSize); // new byte[fileHeader.bfSize];
// TODO: run benchmark on which one is faster
// write file header
//IntPtr tempPtr = Marshal.AllocHGlobal(fileHeaderSize);
//Marshal.StructureToPtr(fileHeader, tempPtr, true);
//Marshal.Copy(tempPtr, dataCopy, 0, fileHeaderSize);
//Marshal.FreeHGlobal(tempPtr);
// would this be faster?
fixed (byte* p = dataCopy)
// a quick check not guaranteed correct,
// compare first 2 bytes to size of struct (which is also the first field)
var test = Marshal.ReadInt16(data);
// should be 40
return test == BITMAPINFOHEADER.GetByteSize();
}
public static bool IsTiff(IntPtr data)
{
Marshal.StructureToPtr(fileHeader, (IntPtr)p, false);
var test = Marshal.ReadInt16(data);
// should be II
return test == 0x4949;
}
// write image
Marshal.Copy(data, dataCopy, fileHeaderSize, (int)fileHeader.bfSize - fileHeaderSize);
return new BufferedData(dataCopy, (int)fileHeader.bfSize, true);
}
return default;
}
public static BufferedData? GetTiffData(IntPtr data)
{
// Find the size of the image so we can turn it into a memory stream...
var headerSize = Marshal.SizeOf(typeof(TIFFHEADER));
var tagSize = Marshal.SizeOf(typeof(TIFFTAG));
var tiffSize = 0;
var tagPtr = data.ToInt64() + headerSize;
for (int i = 0; i < 999; i++)
{
tagPtr += (tagSize * i);
var tag = Marshal.PtrToStructure<TIFFTAG>((IntPtr)tagPtr);
switch (tag.u16Tag)
public static unsafe BufferedData? GetBitmapData(IntPtr data)
{
case 273: // StripOffsets...
case 279: // StripByteCounts...
tiffSize += (int)tag.u32Value;
break;
var infoHeader = Marshal.PtrToStructure<BITMAPINFOHEADER>(data);
if (infoHeader.Validate())
{
var fileHeaderSize = Marshal.SizeOf<BITMAPFILEHEADER>();
var fileHeader = new BITMAPFILEHEADER
{
bfType = 0x4D42, // "BM"
bfOffBits = (uint)fileHeaderSize +
infoHeader.biSize +
(infoHeader.biClrUsed * 4)
};
fileHeader.bfSize = fileHeader.bfOffBits + infoHeader.biSizeImage;
var dataCopy = BufferedData.MemPool.Rent((int)fileHeader.bfSize); // new byte[fileHeader.bfSize];
// TODO: run benchmark on which one is faster
// write file header
//IntPtr tempPtr = Marshal.AllocHGlobal(fileHeaderSize);
//Marshal.StructureToPtr(fileHeader, tempPtr, true);
//Marshal.Copy(tempPtr, dataCopy, 0, fileHeaderSize);
//Marshal.FreeHGlobal(tempPtr);
// would this be faster?
fixed (byte* p = dataCopy)
{
Marshal.StructureToPtr(fileHeader, (IntPtr)p, false);
}
// write image
Marshal.Copy(data, dataCopy, fileHeaderSize, (int)fileHeader.bfSize - fileHeaderSize);
return new BufferedData(dataCopy, (int)fileHeader.bfSize, true);
}
return default;
}
}
if (tiffSize > 0)
{
var dataCopy = BufferedData.MemPool.Rent(tiffSize);// new byte[tiffSize];
Marshal.Copy(data, dataCopy, 0, tiffSize);
return new BufferedData(dataCopy, tiffSize, true);
}
return default;
public static BufferedData? GetTiffData(IntPtr data)
{
// Find the size of the image so we can turn it into a memory stream...
var headerSize = Marshal.SizeOf<TIFFHEADER>();
var tagSize = Marshal.SizeOf<TIFFTAG>();
var tiffSize = 0;
var tagPtr = data.ToInt64() + headerSize;
for (int i = 0; i < 999; i++)
{
tagPtr += (tagSize * i);
var tag = Marshal.PtrToStructure<TIFFTAG>((IntPtr)tagPtr);
switch (tag.u16Tag)
{
case 273: // StripOffsets...
case 279: // StripByteCounts...
tiffSize += (int)tag.u32Value;
break;
}
}
if (tiffSize > 0)
{
var dataCopy = BufferedData.MemPool.Rent(tiffSize);// new byte[tiffSize];
Marshal.Copy(data, dataCopy, 0, tiffSize);
return new BufferedData(dataCopy, tiffSize, true);
}
return default;
}
//internal static Bitmap ReadBitmapImage(IntPtr data)
//{
// Bitmap finalImg = null;
// Bitmap tempImg = null;
// try
// {
// var header = (BITMAPINFOHEADER)Marshal.PtrToStructure(data, typeof(BITMAPINFOHEADER));
// if (header.Validate())
// {
// PixelFormat format = header.GetDrawingPixelFormat();
// tempImg = new Bitmap(header.biWidth, Math.Abs(header.biHeight), header.GetStride(), format, header.GetScan0(data));
// ColorPalette pal = header.GetDrawingPalette(data);
// if (pal != null)
// {
// tempImg.Palette = pal;
// }
// float xdpi = header.GetXDpi();
// float ydpi = header.GetYDpi();
// if (xdpi != 0 && ydpi == 0)
// {
// ydpi = xdpi;
// }
// else if (ydpi != 0 && xdpi == 0)
// {
// xdpi = ydpi;
// }
// if (xdpi != 0)
// {
// tempImg.SetResolution(xdpi, ydpi);
// }
// if (header.IsBottomUpImage)
// {
// tempImg.RotateFlip(RotateFlipType.RotateNoneFlipY);
// }
// finalImg = tempImg;
// tempImg = null;
// }
// }
// finally
// {
// if (tempImg != null)
// {
// tempImg.Dispose();
// }
// }
// return finalImg;
//}
}
//internal static Bitmap ReadBitmapImage(IntPtr data)
//{
// Bitmap finalImg = null;
// Bitmap tempImg = null;
// try
// {
// var header = (BITMAPINFOHEADER)Marshal.PtrToStructure(data, typeof(BITMAPINFOHEADER));
// if (header.Validate())
// {
// PixelFormat format = header.GetDrawingPixelFormat();
// tempImg = new Bitmap(header.biWidth, Math.Abs(header.biHeight), header.GetStride(), format, header.GetScan0(data));
// ColorPalette pal = header.GetDrawingPalette(data);
// if (pal != null)
// {
// tempImg.Palette = pal;
// }
// float xdpi = header.GetXDpi();
// float ydpi = header.GetYDpi();
// if (xdpi != 0 && ydpi == 0)
// {
// ydpi = xdpi;
// }
// else if (ydpi != 0 && xdpi == 0)
// {
// xdpi = ydpi;
// }
// if (xdpi != 0)
// {
// tempImg.SetResolution(xdpi, ydpi);
// }
// if (header.IsBottomUpImage)
// {
// tempImg.RotateFlip(RotateFlipType.RotateNoneFlipY);
// }
// finalImg = tempImg;
// tempImg = null;
// }
// }
// finally
// {
// if (tempImg != null)
// {
// tempImg.Dispose();
// }
// }
// return finalImg;
//}
}
}