How to do memcpy for Byte[]?

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EOS - 04 Dec 2005 01:13 GMT

I guess what I want to do is best explain via the codes here;

Byte[] byteA = new Byte[100000];
Byte[] byteB = new Byte[4];
...
...
...

Now I want to copy 4 bytes from certain portion of the byteA array.

In C/C++, this is what we do;

memcpy(byteB, byteA[X], 4);

Or

memcpy(byteB, byteA+X, 4);

But with C#, I had been stuck for a while with no luck....

Hope you understand what I wanted and could show me the way.

Thanks for your time. Sometime I wish Microsoft could create C# to be nearer
to C/C++. C# is still driving me headache...

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balmerch - 04 Dec 2005 01:38 GMT

You could try:

public void CopyPartialByte(byte[] from, ref byte[] to, int index)
{
for (int x = index; x < (to.Length + index); x++)
to[x - index] = from[x];
}

Then call it:
CopyPartialByte(byteA, ref byteB, index);

Like usual this is off the top of my head, might be an error in the loop
counting but you get the idea I hope.

Chris

> I guess what I want to do is best explain via the codes here;
>
[quoted text clipped - 20 lines]
> Thanks for your time. Sometime I wish Microsoft could create C# to be nearer
> to C/C++. C# is still driving me headache...

Reply to this Message

Daniel O'Connell [C# MVP] - 04 Dec 2005 02:45 GMT

> You could try:
>
[quoted text clipped - 3 lines]
> to[x - index] = from[x];
> }

The ref shouldn't be needed here. An array is a reference type

You can also use Buffer.BlockCopy() to copy from arrays, look it up in MSDN
for the specifics.

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EOS - 04 Dec 2005 09:08 GMT

Thanks! It is really easy to understand and to implement!

> You could try:
>
[quoted text clipped - 37 lines]
>> nearer
>> to C/C++. C# is still driving me headache...

Reply to this Message

Daniel Moth - 04 Dec 2005 01:40 GMT

See my reply to you in the PPC newsgroup

Cheers
Daniel
--
http://www.danielmoth.com/Blog/

>I guess what I want to do is best explain via the codes here;
>
[quoted text clipped - 20 lines]
> Thanks for your time. Sometime I wish Microsoft could create C# to be
> nearer to C/C++. C# is still driving me headache...

Reply to this Message

Jon Skeet [C# MVP] - 04 Dec 2005 07:16 GMT

> I guess what I want to do is best explain via the codes here;
>
> Byte[] byteA = new Byte[100000];
> Byte[] byteB = new Byte[4];

<snip>

See Buffer.BlockCopy, and Array.Copy.

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How to do memcpy for Byte[]?

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