Visual Basic 6.0

File Read Blocks

Demonstrates how to read a file in fixed-size blocks (except for the very last block). Visual Basic 6.0

Dim success As Long
success = 0

' Demonstrates how to read a file in blocks,
' which can be useful when uploading to cloud storage
' services such as Azure, S3, Google, etc.

' For this example, we're simply writing the blocks
' to an output file, and then checking to see if the
' resulting file contents equals the original file contents.

Dim dataBlock() As Byte

Dim facSrc As New CkFileAccess
Dim facDest As New CkFileAccess

Dim srcPath As String
srcPath = "qa_data/xml/hamlet.xml"
Dim destPath As String
destPath = "qa_output/hamletOut.xml"

success = facSrc.OpenForRead(srcPath)
success = facDest.OpenForWrite(destPath)
' Assuming success for the example..

' How many 1024-byte blocks?  (Including 1 for the last partial block)
Dim numBlocks As Long
numBlocks = facSrc.GetNumBlocks(1024)

Dim i As Long
i = 0
Do While (i < numBlocks)
    dataBlock = facSrc.ReadBlock(i,1024)
    If (facSrc.LastMethodSuccess <> 1) Then
        Debug.Print facSrc.LastErrorText
        Exit Sub
    End If

    success = facDest.FileWrite(dataBlock)
    If (success <> 1) Then
        Debug.Print facDest.LastErrorText
        Exit Sub
    End If

    i = i + 1
Loop

facSrc.FileClose 
facDest.FileClose 

Dim bEqual As Long
bEqual = facSrc.FileContentsEqual(srcPath,destPath)
If (bEqual <> 1) Then
    Debug.Print "Something went wrong!"
    Exit Sub
End If

Debug.Print "File successfully copied by blocks."