使用 IntPtr 將 C++ 轉換為 C#

Question

我正忙着將一段代碼從 C++ 改寫成 C#

目前我被困在以下

pCommBuf = new BYTE[nSize+SB_OEM_HEADER_SIZE+SB_OEM_DEV_ID_SIZE+SB_OEM_CHK_SUM_SIZE];
nReceivedBytes = comm_recv( pCommBuf, nSize+SB_OEM_HEADER_SIZE+SB_OEM_DEV_ID_SIZE+SB_OEM_CHK_SUM_SIZE, gCommTimeOut );
if( nReceivedBytes != nSize+SB_OEM_HEADER_SIZE+SB_OEM_DEV_ID_SIZE+SB_OEM_CHK_SUM_SIZE )
{
    if(pCommBuf)
        delete pCommBuf;
    return PKT_COMM_ERR;
}
memcpy(Buf, pCommBuf, SB_OEM_HEADER_SIZE+SB_OEM_DEV_ID_SIZE);
memcpy(pBuf, pCommBuf+SB_OEM_HEADER_SIZE+SB_OEM_DEV_ID_SIZE, nSize);
wReceivedChkSum = *(WORD*)(pCommBuf+nSize+SB_OEM_HEADER_SIZE+SB_OEM_DEV_ID_SIZE);

我有代碼工作到這一點

//memcpy(Buf, pCommBuf, SB_OEM_HEADER_SIZE+SB_OEM_DEV_ID_SIZE);
Marshal.Copy(pCommBuf, Buf, 0, (int)(SB_OEM_HEADER_SIZE + SB_OEM_DEV_ID_SIZE)); // This works
//memcpy(pBuf, pCommBuf+SB_OEM_HEADER_SIZE+SB_OEM_DEV_ID_SIZE, nSize);

我不知道如何在 C# 中做pCommBuf+SB_OEM_HEADER_SIZE+SB_OEM_DEV_ID_SIZE ，pCommBuff 是一個IntPtr和 C++ Byte*

Answer 1

您只需要更改第二個副本的起始偏移量：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Runtime.InteropServices;

namespace ConsoleApplication1
{
    class Program
    {
        const int SB_OEM_HEADER_SIZE = 10;
        const int SB_OEM_DEV_ID_SIZE = 10;
        const int SB_OEM_CHK_SUM_SIZE = 10;

        static void Main(string[] args)
        {

            int nSize = 1024;
            byte[] nBuf = new byte[nSize];
            byte[] Buf = new byte[SB_OEM_HEADER_SIZE + SB_OEM_DEV_ID_SIZE];

            IntPtr pCommBuf = Marshal.AllocHGlobal(nSize + SB_OEM_HEADER_SIZE + SB_OEM_DEV_ID_SIZE + SB_OEM_CHK_SUM_SIZE);
            Marshal.Copy(nBuf, 0, pCommBuf, nSize);
            Marshal.Copy(pCommBuf + nSize , Buf, 0, (int)(SB_OEM_HEADER_SIZE + SB_OEM_DEV_ID_SIZE));

        }
    }
}