如何通过一个操作将字节数组转换为联合结构

本文关键字：转换 数组 字节数 结构 字节 何通过 操作 一个 | 更新日期: 2023-09-27 18:18:22

我在c#中声明了类似c++中的联合的东西:

[StructLayout(LayoutKind.Explicit, Size = 5)]
public struct Marker
{
        [FieldOffset(0)] public byte label;
        [FieldOffset(1)] public int count;
        [FieldOffset(1)] private byte count_0;
        [FieldOffset(2)] private byte count_1;
        [FieldOffset(3)] private byte count_2;
        [FieldOffset(4)] private byte count_3;
}

我也有byte[] bytes与尺寸5。我需要将数组转换为Marker对象。我可以这样做:

var marker = new Marker 
{
    label = bytes[0],
    count = BitConverter.ToInt32(bytes, 1)
}

或:

var marker = new Marker 
{
    label = bytes[0],
    count_0 = bytes[1],
    count_1 = bytes[2],
    count_2 = bytes[3],
    count_3 = bytes[4]
}

那没关系，但我认为从性能角度来看，可以通过更优化的方式做到-只是点marker到bytes的第一个字节。我试图找到这样的东西:

BitConverter.To<Marker>(bytes);

如何将字节数组转换为联合结构的一个操作?

如何通过一个操作将字节数组转换为联合结构

应该可以了

    static void Main(string[] args)
    {
        //Creating test data
        List<byte> data = new List<byte>();
        data.Add(123);
        data.AddRange(BitConverter.GetBytes((int)123456));
        //Converting test data to Struct
        Marker m = StructFromBytes<Marker>(data.ToArray());
        //Check if it works
        Console.WriteLine(m.label); //Prints 123
        Console.WriteLine(m.count); //Prints 123456
    }
    private static T StructFromBytes<T>(byte[] bytes)
    {
        int structSize = Marshal.SizeOf(typeof(T));
        byte[] structBytes = new byte[structSize];
        Array.Copy(bytes, 0, structBytes, 0, structSize);
        GCHandle handle = GCHandle.Alloc(structBytes, GCHandleType.Pinned);
        T theStructure = (T)Marshal.PtrToStructure(handle.AddrOfPinnedObject(), typeof(T));
        handle.Free();
        return theStructure;
    }

你可以创建一个构造函数:

[StructLayout(LayoutKind.Explicit, Size = 5)]
public struct Marker
{
    [FieldOffset(0)] public byte label;
    [FieldOffset(1)] public int count;
    [FieldOffset(1)] private byte count_0;
    [FieldOffset(2)] private byte count_1;
    [FieldOffset(3)] private byte count_2;
    [FieldOffset(4)] private byte count_3;
    public Marker(byte[] bytes)
    {
       label = bytes[0];
       count_0 = bytes[1];
       count_1 = bytes[2];
       count_2 = bytes[3];
       count_3 = bytes[4];
    }
}

或操作符重载:

[StructLayout(LayoutKind.Explicit, Size = 5)]
public struct Marker
{
    [FieldOffset(0)] public byte label;
    [FieldOffset(1)] public int count;
    [FieldOffset(1)] private byte count_0;
    [FieldOffset(2)] private byte count_1;
    [FieldOffset(3)] private byte count_2;
    [FieldOffset(4)] private byte count_3;
    public static explicit operator Marker(byte[] bytes)
    {
       Marker result = new Marker();
       result.label = bytes[0];
       result.count_0 = bytes[1];
       result.count_1 = bytes[2];
       result.count_2 = bytes[3];
       result.count_3 = bytes[4];
       return result;
    }
}

这两种解决方案都可以使创建结构体变成一行代码:

Marker marker = new Marker(bytes);
Marker marker = (Marker)bytes;
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