CODEWITHSUNDEEP
c#c++
KristijanSharp
KristijanSharp

Reputation: 133

Convert piece of code from c++ to c#

i'm trying to convert code from c++ to c#.. but i'm stuck. Can somebody let me know where i'm wrong?

C++ code is:

void CALLBACK Test(void *buffer, DWORD length)
{
  BYTE *b=(BYTE*)buffer, temp[20000];
  DWORD p=0;
  while (p<length) 
  {
    DWORD c=min(length-p, sizeof(temp));
    memcpy(temp, b+p, c);
    c=SendData(dummy, temp, c);
    if (c==-1) break;
    p+=c;
  }
}

where is SendData(int, byte[], int)

And current c# code

void Test(IntPtr buffer, int length)
{

        byte[] temp = new byte[20000];
        byte[] b = new byte[length];
        Marshal.Copy(buffer, b, 0, length);

   long p=0;
   while (p<length) 
   {
    long c=Math.Min(length-p, 20000);
    Array.Copy(temp, b+p, c);
    c=SendData(dummy, temp, (int)c);
    if (c==-1) break;
    p+=c;
  }
}

I'm not sure did I did it correctly, but I can see I cannot apply operator + to b+s because it's long and byte[].

Thanks

Upvotes: 0

Views: 219

Answers (3)

dgvid
dgvid

Reputation: 26633

In C++ you may add a DWORD (an int, really) to a pointer and the compiler knows to offset the address of the pointer by the specified amount. C# doesn't let you do that, normally. (There is a way to do pointer arithmetic in C#, but don't.) So, in the C# version, you need another way to copy at offset p relative to the start of b. One of the overloads of Array.Copy will let you do that. Something like:

Array.Copy(temp, 0, b, p, c);

Upvotes: 2

Nathan Monteleone
Nathan Monteleone

Reputation: 5470

I think you want to use the 5-arg version of Array.Copy, which lets you pass offsets into both the start and destination arrays. This is the more "C#" way of doing things as opposed to pointer arithmetic.

Upvotes: 2

Cameron Hotchkies
Cameron Hotchkies

Reputation: 1509

You may want to look at: How to split a byte array, because that is in effect what you are trying to accomplish with the b+pportion.

Upvotes: 0

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