[ { "Id": "126867", "ThreadId": "38259", "Html": "I'm trying to check zip file using this code, but get an exception (OutOfMemoryException) when I try to extract big files.
\r\nThere are other ways to check corrupted file?
\r\nThanks
\r\nsorry for my english :p
\r\n \r\n

Private

\r\n\r\n

 

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Function checkCRCZip(ByVal filezip As String, ByVal dir As String) As String
\r\nDim 

\r\n\r\n

 

\r\n\r\n

ZipFileToCheck As String = filezip
\r\nDim mStream As MemoryStream
\r\nDim output As String = ""
\r\nDim zip As ZipFile = ZipFile.Read(ZipFileToCheck)
\r\nDim zEntry As ZipEntry
\r\n
\r\n    Try
\r\n        For Each zEntry In Zip
\r\n            mStream = New MemoryStream()
\r\n            zEntry.Extract(mStream) 
\r\n            output = String.Format("0x{1:X8}", zEntry.FileName, zEntry.Crc32)
\r\n        Next  
\r\n    Catch ex As BadReadException
\r\n        MessageBox.Show(ex.Message.ToString)
\r\n        output = ""
\r\n    Catch ex As BadCrcException
\r\n        MessageBox.Show(ex.Message.ToString)
\r\n        output = ""
\r\n    End Try
\r\n
\r\ncheckCRCZip = output
\r\nEnd Function\r\n

 

\r\n

\r\n

 

\r\n

\r\n

\r\n

 

\r\n

 

\r\n", "PostedDate": "2008-10-22T06:07:27.85-07:00", "UserRole": null, "MarkedAsAnswerDate": null }, { "Id": "126902", "ThreadId": "38259", "Html": "The most reliable way to "check" a zip file is to actually extract all the entries within it. 
\r\nThere can be a corruption at any point in the file, and the only way to find out is to extract each entry.
\r\nThis validates the checksums and data sizes and so on.
\r\n
\r\nIn your case, you are extracting to a memory stream which keeps all file (entry) contents in memory. For large files this is a problem, and you get the out-of-memory exception.
\r\n
\r\nI think what you may want is a stream with no storage at all, a "bit bucket". 
\r\n
\r\nTry System.IO.Stream.Null . 
\r\n", "PostedDate": "2008-10-22T07:48:26.253-07:00", "UserRole": null, "MarkedAsAnswerDate": null }, { "Id": "127114", "ThreadId": "38259", "Html": "I can't find Stream in VB2005.
\r\nThere are only StreamReader and StreamWriter.
\r\n
\r\nEDIT: Sorry, I find it :p
\r\n
\r\n", "PostedDate": "2008-10-22T23:49:37.163-07:00", "UserRole": null, "MarkedAsAnswerDate": null }, { "Id": "127373", "ThreadId": "38259", "Html": "

Glad you found it.
\r\n
\r\nHere's some code for anyone else who wants to try this: 

\r\n
            If File.Exists(ZipToCheck) Then\r\n\r\n                Console.WriteLine("Checking the zip file: {0}", ZipToCheck)\r\n\r\n                Dim bitBucket As System.IO.Stream\r\n                bitBucket = System.IO.Stream.Null\r\n\r\n                Using zip As ZipFile = ZipFile.Read(ZipToCheck)\r\n                    Dim zEntry As ZipEntry\r\n\r\n                    Try\r\n                          For Each zEntry In Zip\r\n                              If NOT zEntry.IsDirectory Then \r\n                                  zEntry.Extract(bitBucket) \r\n                                  Console.WriteLine("  {0,-48}   0x{1:X8}", zEntry.FileName, zEntry.Crc32)\r\n                              End If\r\n                          Next  \r\n                    Catch ex As BadReadException\r\n                          Console.WriteLine(ex.Message.ToString)\r\n                    Catch ex As BadCrcException\r\n                          Console.WriteLine(ex.Message.ToString)\r\n                    End Try\r\n                End Using\r\n\r\n            Else\r\n                Console.WriteLine("The zip file '{0}' does not exist.", ZipToCheck)\r\n            End If\r\n
\r\n

If you think it is valuable, I could add a method to the ZipFile class to do this. It could be a matter of adding an overload to the existing static ZipFile.IsZipFile() method.

\r\n

 

\r\n", "PostedDate": "2008-10-23T17:28:03.46-07:00", "UserRole": null, "MarkedAsAnswerDate": null } ]