File Through Winsock & Progress on bar

Hey,

How do you send a file through a winsock connection. I mean if it was a simple text file i know i could just read it in then use send() to send it through, but say its a bigger file such as a bitmap that i can just do that with or can I? If i can do it like that can someone explain how it is done.

Also i want to display the progress of the transfer on a progress bar. I can make a progress bar but i dont know how to make it interact with the file transfer and show its progress.


Thanks for any help

Cheers
TNT

Usually transfers of larger files include one large loop that reads from the hard drive (or memory if you've read the entire file in), sends the data, and calculates its progress and rate. So yes, you could do the same with a bitmap, but don't send it all at once.

The Winsock function TransmitFile() allows you to send a block of data before and after a transfer along with the file. There is, however, no way to track its progress or calculate a rate.

Set the progress bar's maximum amount to the size of the file, and the minimum amount to zero (or to an offset if the transfer begins in the middle of a file). Every time the bar needs repainting, see how much has been downloaded with a global variable the send loop continuously updates, and set that as the bar's current value.

When we send a file I get the size as an int first, I set the progressbar to this size. As data is read, send the size rec to the progress bar.

I have a VERY complicated function for reading in the files. They are of different sizes, sockets and types.

while(Data_Used<Data_Read)

switch(iBuffer)

case(1)
read the sizeof(int)=total_incomming
Data_Used+=sizeof(int)
alloc mem for outgoing buffer this size
iBuffer++

case (2)
copy mem into outgoing buffer
//here it gets tricky as must allow for not getting all the data in one read
//also for end of one item and start of another in same read
Data_Used+=Data_Copied
if(Data_Copied==total_incomming)
iBuffer++

case (3)
send to app funct to deal with data
iBuffer=1
free outgoing buffer

end of while loop

Storing the same as an int means that you can't have files larger than 32k. Of course some compilers has 32-bit ints but using long is better.

True, I forgot we are compressing them for transfer.

Should use long.