从数据来自C/C++结构的byte[]数组填充C#结构的最佳方法是什么?C结构看起来像这样(我的C非常生疏):
typedef OldStuff {
CHAR Name[8];
UInt32 User;
CHAR Location[8];
UInt32 TimeStamp;
UInt32 Sequence;
CHAR Tracking[16];
CHAR Filler[12];
}
并会填入如下内容:
[StructLayout(LayoutKind.Explicit, Size = 56, Pack = 1)]
public struct NewStuff
{
[MarshalAs(UnmanagedType.ByValTStr, SizeConst = 8)]
[FieldOffset(0)]
public string Name;
[MarshalAs(UnmanagedType.U4)]
[FieldOffset(8)]
public uint User;
[MarshalAs(UnmanagedType.ByValTStr, SizeConst = 8)]
[FieldOffset(12)]
public string Location;
[MarshalAs(UnmanagedType.U4)]
[FieldOffset(20)]
public uint TimeStamp;
[MarshalAs(UnmanagedType.U4)]
[FieldOffset(24)]
public uint Sequence;
[MarshalAs(UnmanagedType.ByValTStr, SizeConst = 16)]
[FieldOffset(28)]
public string Tracking;
}
如果OldStuff
是作为byte[]数组传递的,那么将OldStuff
复制到NewStuff
的最佳方法是什么?
我目前正在做类似以下的事情,但感觉有点笨拙。
GCHandle handle;
NewStuff MyStuff;
int BufferSize = Marshal.SizeOf(typeof(NewStuff));
byte[] buff = new byte[BufferSize];
Array.Copy(SomeByteArray, 0, buff, 0, BufferSize);
handle = GCHandle.Alloc(buff, GCHandleType.Pinned);
MyStuff = (NewStuff)Marshal.PtrToStructure(handle.AddrOfPinnedObject(), typeof(NewStuff));
handle.Free();
有没有更好的方法来实现这一点?
与固定内存和使用Marshal.PtrStructure
相比,使用BinaryReader
类会带来性能上的提升吗
发布于 2008-08-05 21:29:40
根据我在该上下文中看到的,您不需要将SomeByteArray
复制到缓冲区中。您只需从SomeByteArray
获取句柄,固定它,使用PtrToStructure
复制IntPtr
数据,然后释放即可。不需要拷贝。
这将是:
NewStuff ByteArrayToNewStuff(byte[] bytes)
{
GCHandle handle = GCHandle.Alloc(bytes, GCHandleType.Pinned);
try
{
NewStuff stuff = (NewStuff)Marshal.PtrToStructure(handle.AddrOfPinnedObject(), typeof(NewStuff));
}
finally
{
handle.Free();
}
return stuff;
}
通用版本:
T ByteArrayToStructure<T>(byte[] bytes) where T: struct
{
T stuff;
GCHandle handle = GCHandle.Alloc(bytes, GCHandleType.Pinned);
try
{
stuff = (T)Marshal.PtrToStructure(handle.AddrOfPinnedObject(), typeof(T));
}
finally
{
handle.Free();
}
return stuff;
}
更简单的版本(需要unsafe
开关):
unsafe T ByteArrayToStructure<T>(byte[] bytes) where T : struct
{
fixed (byte* ptr = &bytes[0])
{
return (T)Marshal.PtrToStructure((IntPtr)ptr, typeof(T));
}
}
发布于 2017-01-25 02:40:34
下面是accepted answer的一个异常安全版本:
public static T ByteArrayToStructure<T>(byte[] bytes) where T : struct
{
var handle = GCHandle.Alloc(bytes, GCHandleType.Pinned);
try {
return (T) Marshal.PtrToStructure(handle.AddrOfPinnedObject(), typeof(T));
}
finally {
handle.Free();
}
}
发布于 2008-08-31 10:03:39
注意包装问题。在您给出的示例中,所有字段都处于明显的偏移量,因为所有字段都位于4字节边界上,但情况并不总是如此。默认情况下,Visual C++打包在8字节边界上。
https://stackoverflow.com/questions/2871
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