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Public Class ZipUtil
Public Function CompressFile(ByVal sourceFile As String, ByVal destinationFile As String) As String
' make sure the source file is there
If File.Exists(sourceFile) = False Then
Throw New FileNotFoundException
End If
' Create the streams and byte arrays needed
Dim buffer As Byte() = Nothing
Dim sourceStream As FileStream = Nothing
Dim destinationStream As FileStream = Nothing
Dim compressedStream As GZipStream = Nothing
Dim ReturnValue As String = Nothing
Try
' Read the bytes from the source file into a byte array
sourceStream = New FileStream(sourceFile, FileMode.Open, FileAccess.Read, FileShare.Read)
' Read the source stream values into the buffer
buffer = New Byte(sourceStream.Length) {}
Dim checkCounter As Integer = sourceStream.Read(buffer, 0, buffer.Length)
' Open the FileStream to write to
destinationStream = New FileStream(destinationFile, FileMode.OpenOrCreate, FileAccess.Write)
' Create a compression stream pointing to the destiantion stream
compressedStream = New GZipStream(destinationStream, CompressionMode.Compress, True)
'Now write the compressed data to the destination file
compressedStream.Write(buffer, 0, buffer.Length)
ReturnValue = "Success"
Catch ex As ApplicationException
ReturnValue = ex.Message
Finally
' Make sure we allways close all streams
If Not (sourceStream Is Nothing) Then
sourceStream.Close()
End If
If Not (compressedStream Is Nothing) Then
compressedStream.Close()
End If
If Not (destinationStream Is Nothing) Then
destinationStream.Close()
End If
End Try
Return ReturnValue
End Function
Public Function DecompressFile(ByVal sourceFile As String, ByVal destinationFile As String) As String
Dim ReturnValue As String = Nothing
' make sure the source file is there
If File.Exists(sourceFile) = False Then
Throw New FileNotFoundException
End If
' Create the streams and byte arrays needed
Dim sourceStream As FileStream = Nothing
Dim destinationStream As FileStream = Nothing
Dim decompressedStream As GZipStream = Nothing
Dim quartetBuffer As Byte() = Nothing
Try
' Read in the compressed source stream
sourceStream = New FileStream(sourceFile, FileMode.Open)
' Create a compression stream pointing to the destiantion stream
decompressedStream = New GZipStream(sourceStream, CompressionMode.Decompress, True)
' Read the footer to determine the length of the destiantion file
quartetBuffer = New Byte(4) {}
Dim position As Integer = CType(sourceStream.Length, Integer) - 4
sourceStream.Position = position
sourceStream.Read(quartetBuffer, 0, 4)
sourceStream.Position = 0
Dim checkLength As Integer = BitConverter.ToInt32(quartetBuffer, 0)
Dim buffer(checkLength + 100) As Byte
Dim offset As Integer = 0
Dim total As Integer = 0
' Read the compressed data into the buffer
While True
Dim bytesRead As Integer = decompressedStream.Read(buffer, offset, 100)
If bytesRead = 0 Then
Exit While
End If
offset += bytesRead
total += bytesRead
End While
' Now write everything to the destination file
destinationStream = New FileStream(destinationFile, FileMode.Create)
destinationStream.Write(buffer, 0, total)
' and flush everyhting to clean out the buffer
destinationStream.Flush()
ReturnValue = "Success"
Catch ex As ApplicationException
ReturnValue = ex.Message
Finally
' Make sure we allways close all streams
If Not (sourceStream Is Nothing) Then
sourceStream.Close()
End If
If Not (decompressedStream Is Nothing) Then
decompressedStream.Close()
End If
If Not (destinationStream Is Nothing) Then
destinationStream.Close()
End If
End Try
Return ReturnValue
End Function
Protected Overrides Sub Finalize()
MyBase.Finalize()
End Sub
End Class |
