从字节数组中读取C＃中的C / C ++数据结构 [英] Reading a C/C++ data structure in C# from a byte array

问题描述

从数据来自C / C ++结构体的byte []数组中填充C＃结构的最佳方式是什么？ C结构将看起来像这样（我的C非常生锈）：

What would be the best way to fill a C# struct from a byte[] array where the data was from a C/C++ struct? The C struct would look something like this (my C is very rusty):

typedef OldStuff {
    CHAR Name[8];
    UInt32 User;
    CHAR Location[8];
    UInt32 TimeStamp;
    UInt32 Sequence;
    CHAR Tracking[16];
    CHAR Filler[12];
}

并填写如下内容：

[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;
}

最好的方法是复制 OldStuff 到 NewStuff ，如果 OldStuff 被传递为byte []数组？

What is best way to copy OldStuff to NewStuff, if OldStuff was passed as byte[] array?

我目前正在做如下的事情，但感觉很笨重。

I'm currently doing something like the following, but it feels kind of clunky.

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();

有更好的方法来实现吗？

Is there better way to accomplish this?

将使用 BinaryReader 类提供任何性能优势，固定内存并使用 Marshal.PtrStructure ？

Would using the BinaryReader class offer any performance gains over pinning the memory and using Marshal.PtrStructure?

推荐答案

从我可以看到的那个上下文中，你不需要复制SomeByteArray进入缓冲区您只需要从SomeByteArray获取句柄，将其固定，使用PtrToStructure复制IntPtr数据，然后释放。不需要副本。

From what I can see in that context, you don't need to copy SomeByteArray into a buffer. You simply need to get the handle from SomeByteArray, pin it, copy the IntPtr data using PtrToStructure and then release. No need for a copy.

这将是：

NewStuff ByteArrayToNewStuff(byte[] bytes)
{
    GCHandle handle = GCHandle.Alloc(bytes, GCHandleType.Pinned);
    NewStuff stuff = (NewStuff)Marshal.PtrToStructure(handle.AddrOfPinnedObject(), typeof(NewStuff));
    handle.Free();
    return stuff;
}

通用版本：

T ByteArrayToStructure<T>(byte[] bytes) where T: struct 
{
    GCHandle handle = GCHandle.Alloc(bytes, GCHandleType.Pinned);
    T stuff = (T)Marshal.PtrToStructure(handle.AddrOfPinnedObject(), typeof(T));
    handle.Free();
    return stuff;
}

...

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