C无符号'char**out'到C#`byte[]`

这是libeay32.dll（）中的函数：

如何用C#来描述它（如果我想得到一个字节[]）

代码：

我不喜欢这样，因为我认为结果是unicode

回答

        [DllImport(DLLNAME, CallingConvention = CallingConvention.Cdecl)]
        public extern static int i2o_ECPublicKey(IntPtr encKey, ref IntPtr outPar);

        [DllImport(DLLNAME, CallingConvention = CallingConvention.Cdecl)]
        public static extern int i2o_ECPublicKey(IntPtr encKey, int outPar);


        //Pass *out as null for required buffer length.
        int reqLen = i2o_ECPublicKey(k, 0);

        Byte[] outBuf = new Byte[reqLen];
        IntPtr unmanagedOut = Marshal.AllocCoTaskMem(outBuf.Length);
        int res = i2o_ECPublicKey(k, ref unmanagedOut);
        if (res == reqLen)
        {
            unmanagedOut -= reqLen; // because i2o_ECPublicKey add size to unmanagedOut
            Marshal.Copy(unmanagedOut, outBuf, 0, outBuf.Length);
        }
        Marshal.FreeCoTaskMem(unmanagedOut);

---

我认为要手动执行此操作，需要使用Marshal.Copy将数组从非托管内存复制到托管字节[]。（注意，代码未经测试）

---

通过使用

GetBytes

StringBuilder outPar;
string result = "";
byte[] parbytes = System.Text.Encoding.Unicode.GetBytes(outPar.ToString());
foreach(byte parbyte in parbytes)
{
    result+= Convert.ToChar(parbyte);
}
return result;

        [DllImport(DLLNAME, CallingConvention = CallingConvention.Cdecl)]
        public extern static int i2o_ECPublicKey(IntPtr encKey, ref IntPtr outPar);

        [DllImport(DLLNAME, CallingConvention = CallingConvention.Cdecl)]
        public static extern int i2o_ECPublicKey(IntPtr encKey, int outPar);


        //Pass *out as null for required buffer length.
        int reqLen = i2o_ECPublicKey(k, 0);

        Byte[] outBuf = new Byte[reqLen];
        IntPtr unmanagedOut = Marshal.AllocCoTaskMem(outBuf.Length);
        int res = i2o_ECPublicKey(k, ref unmanagedOut);
        if (res == reqLen)
        {
            unmanagedOut -= reqLen; // because i2o_ECPublicKey add size to unmanagedOut
            Marshal.Copy(unmanagedOut, outBuf, 0, outBuf.Length);
        }
        Marshal.FreeCoTaskMem(unmanagedOut);

public extern static int i2o_ECPublicKey (IntPtr encKey, ref IntPtr outPar);

...
//Pass *out as null for required buffer length.
int reqLen = i2o_ECPublicKey(key, null);

Byte[] outBuf = new Byte[reqLen];
IntPtr unmanagedOut = Marshal.AllocCoTaskMem(outBuf.Length);
int res = i2o_ECPublicKey(key, ref unmanagedOut);
if (res == 1) {
    Marshal.Copy(unmanaged, outBuf, 0, outBuf.Length);
}
Marshal.FeeCoTaskMem(unmanagedOut);

StringBuilder outPar;
string result = "";
byte[] parbytes = System.Text.Encoding.Unicode.GetBytes(outPar.ToString());
foreach(byte parbyte in parbytes)
{
    result+= Convert.ToChar(parbyte);
}
return result;