Winsock+Open A File==>{EXPERT}

[aquarius]

Hello! I am in a little bit of a "jam" here!! I am creating a Winsock Client/Host application..

I have everything the way i want so far, ., Except for one little problem! When i want the host portion of my program to send a file.. The program first has to open this specific file into a Binary Variable and then it begins sending it into chunks!

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Public Sub SendFile(FileName As String, Transfer As Winsock)
Dim FreeF, Stoper As Integer
Dim LocData(1 To 2048) As Byte

FreeF = FreeFile

Open FileName For Binary As #FreeF

Do While Not EOF(FreeF)

Get #FreeF, , LocData 'Get data from the file nCnt is from where to start the get

Transfer.SendData LocData 'Send the chunk

Loop

Close #FreeF

Sleep 200

End Sub
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////////////////////////////////////////////////

But the Problem with this is that if i want to send a larger file (lets say 50MB++) .,,. the program really uses up the (HOST) HD space becasue it stores the whole contents of the file in to 1 variable in my vb application , and then it gradually begins sending the chunks of data.

I guess what i am primarily asking, is , is there a way to open a specific part of a file and load it into a variable.,.,

Lets say, i want the first 200 bytes of a file loaded into a variable withought having loaded the whole file into my application!

and then proceeding from the 200 byte section to the 400 byte section.,.,giving me again another 200 byte chunk of data.(200 byte was used just for example , doesn't have to be 200)

To clarify this a little bit more,, I want to open up a specific part of a file in to a variable withought having first gone through the whole contents of the file!

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I know this is long, But i would really appreciate it if anyone helped me here!
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[PaulLewis]

After a careful read of your code, it seems fine to me. You are breaking the file down into 2048 byte chunks and sending each chunk.

YOu said that your problem is that you read the entire file into memory, but where does this happen?

Cheers

[PaulLewis]

This time I read it and got the idea you might be wanting to restart the reading from a particular point (say 25MB of that 50MB whopper?). So perhaps you are writing code to automatically resume an aborted upload?

In that case, pay special attention to the line in your code:

Get #FreeF, , LocData 'Get data from the file nCnt is from where to start the get

Looking at the comment here, I presume you have cut and pasted this from someplace else? No matter if you did, just keep in mind that the Get # command allows as the second parameter an offset value. This means you can specify where to start the reading from (i.e. the exact byte).

Alternatively you use the seek procedure to point the open file to the starting point.

Hope it helps

Here is some code that will help you. It will open the file and read the amount specified by chunksize and automatically advance through the file. When it gets to the last chunk, which is likely to be smaller than the chunksize, the chunksize will automatically re-adjust its size to accomdate for the last chunk.

'sending code
    'open in binary
    Open FullFilename For Binary Access Read As #1  
        Do Until EOF(1)
            If StopNow = True Then   'sudden stop
                'rest the variable so it won't stop itself
                StopNow = False  'next time round
                Close #1 
                Exit Do  'exit the loop
            End If
            're-adjust chunksize if it is too large
            If FSize - Loc(1) <= Chunksize Then
                Chunksize = FSize - Loc(1)
                'indicates this is the last packet
                Last = True  
            End If
            SData = Space$(Chunksize)   'make empty string
            Get #1, , SData 'get data into var
            wskfile.SendData SData  'send it
            DoEvents
            If Last = True Then 
                'exit loop because of its last packet
                Last = False
                Exit Do
            End If
        Loop
    Close #1

and the receiveing code

Private Sub wskFile_DataArrival(ByVal bytesTotal As Long)
    Dim Incoming As String
    Dim count As Integer
    'bytesTotal is set to the size of the file
    bytesTotal = FSize   

    If StopNow = True Then
        Exit Sub
    End If
    
    wskFile.GetData Incoming
    
    Put #2, , Incoming     'write data into file
    'if the size of the received file is equal to the       
    'filesize the stop
    If LOF(2) = FSize Then           
        Close #2  
        Wait (1)
        Call ResetConnection
    End If
End Sub

Sunny