How to convert uint8 array to int?

Development Programming & Scripting C++
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1

I’m writing socket to receive data code

This my code:

	TArray<uint8> ReceiveData;
	uint8 element = 0;
	while (true)
	{
		ReceiveData.Init(element, 1024u);
		int32 read = 0;
		Socket->Recv(ReceiveData.GetData(), ReceiveData.Num(), read);
	}

I can receive data ,

I’m trying to receive an int data,

how to convert uint8 array to int?

2

Do you receiving int32 data or you want to convert bytes to int32? note that uint8 is blueprint/property editor compatible as Byte type so you can actually use it without any conversion

3

I will try

4

I want to send the data I received to the blueprint

5

My message format looks like this:

int PlayerID, string PlayerName

I received uint8

I am looking for a way to turn it into the original type

Maybe 1 int is equal to 4 uint8?

6

I just found out that uint8 is unsigned char

7

This is my code, but it’s still wrong:

            TArray<uint8> ReceiveData;
	uint8 element = 0;
	TArray<uint8> Buffer;

	while (true)
	{
		ReceiveData.Init(element, 4);
		int32 read = 0;
		Socket->Recv(ReceiveData.GetData(), ReceiveData.Num(), read);
		int test_int = static_cast<int>(*(ReceiveData.GetData()));
		NetworkMgr->RecvData(test_int);
	}

I’m trying to modify it…

8

I want to convert bytes to int

9

This is my code：

	uint8 recvBuffer[4];
	uint8 element = 0;

	while (true)
	{
		int32 read = 0;
		Socket->Recv(recvBuffer, 4, read, ESocketReceiveFlags::WaitAll);
		int test_int = (int) *recvBuffer;
		NetworkMgr->RecvData(test_int);
	}

It looks like it’s working,
But it still can not pass a negative number

10

I sent this data from the server:

int PackageLength (4 bit) , int ProtoID (4 bit) , int LoginResult (4 bit) , string LoginKey (32 bit)

The value of the server is:

PackageLength = 44 , ProtoID = 1 , LoginResult = -1 , LoginKey ="\x00\x00\x00\x00…"

My ue4 client received data is: (Currently only consider the int type)

PackageLength = 44 , ProtoID = 1 , LoginResult = 255 , …

11

This is my solution:

int ABaseNetworkMgr::GetIntByBuffer(TArray<uint8> Buffer, int Offset)
{
	int int_value;
	unsigned char char_list[4];
	for (int i = 0; i < 4; i++)
	{
		char_list[i] = Buffer.GetData()[i+ Offset];
	}
	memcpy(&int_value, char_list, 4);
	return int_value;
}

But I did not take into account the case of Big-Endian and Little-Endian of.

And in cross-platform, memory allocation may be a problem.

1 Like
12

Cross-platform seems to be able to use FMemory :: Memcpy ()