如何在C#中将字节数组转换为double数组？

Question

我有一个包含双精度值的字节数组.我想将它转换为双数组.在C#中有可能吗？

字节数组看起来像:

byte[] bytes; //I receive It from socket

double[] doubles;//I want to extract values to here

我用这种方式创建了一个字节数组(C++):

double *d; //Array of doubles
byte * b = (byte *) d; //Array of bytes which i send over socket

Answer 1

你不能转换数组类型; 然而:

byte[] bytes = ...
double[] values = new double[bytes.Length / 8];
for(int i = 0 ; i < values.Length ; i++)
    values[i] = BitConverter.ToDouble(bytes, i * 8);

或(交替):

byte[] bytes = ...
double[] values = new double[bytes.Length / 8];
Buffer.BlockCopy(bytes, 0, values, 0, values.Length * 8);

应该做.您也可以在unsafe代码中执行此操作:

byte[] bytes = ...
double[] values = new double[bytes.Length / 8];
unsafe
{
    fixed(byte* tmp = bytes)
    fixed(double* dest = values)
    {
        double* source = (double*) tmp;
        for (int i = 0; i < values.Length; i++)
            dest[i] = source[i];
    }
}

不过我不推荐这样做

Answer 2

我将从这里C#unsafe值类型数组添加对超不安全代码的引用到字节数组转换

请注意,它基于C#的未记录的"功能",所以明天它可能会死亡.

[StructLayout(LayoutKind.Explicit)]
struct UnionArray
{
    [FieldOffset(0)]
    public byte[] Bytes;

    [FieldOffset(0)]
    public double[] Doubles;
}

static void Main(string[] args)
{
    // From bytes to floats - works
    byte[] bytes = { 0, 1, 2, 4, 8, 16, 32, 64 };
    UnionArray arry = new UnionArray { Bytes = bytes };

    for (int i = 0; i < arry.Bytes.Length / 8; i++)
        Console.WriteLine(arry.Doubles[i]);   
}

这种方法的唯一优点是它不会真正"复制"数组,因此在空间和时间上的O(1)是复制O(n)数组的其他方法.