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Function WriteBLOB(sField As String, Destination As String)
Dim NumBlocks As Integer, DestFile As Integer, i As Integer
Dim FileLength As Long, LeftOver As Long
Dim FileData As String
Dim RetVal As Variant
On Error GoTo Err_WriteBLOB
Dim T As Object
Set T = CurrentDb.OpenRecordset("SELECT * FROM BLOB", , dbOpenDynaset)
req = "SELECT * FROM BLOB"
' Get the size of the field.
FileLength = T(sField).FieldSize()
If FileLength = 0 Then
WriteBLOB = 0
Exit Function
End If
' Calculate number of blocks to write and leftover bytes.
NumBlocks = FileLength \ BlockSize
LeftOver = FileLength Mod BlockSize
' Remove any existing destination file.
DestFile = FreeFile
Open Destination For Output As DestFile
Close DestFile
' Open the destination file.
Open Destination For Binary As DestFile
' SysCmd is used to manipulate the status bar meter.
RetVal = SysCmd(acSysCmdInitMeter, _
"Writing BLOB", FileLength / 1000)
' Write the leftover data to the output file.
FileData = T(sField).GetChunk(0, LeftOver)
Put DestFile, , FileData
' RetrieveLinkedPath = FileData
' Update the status bar meter.
RetVal = SysCmd(acSysCmdUpdateMeter, LeftOver / 1000)
' Write the remaining blocks of data to the output file.
For i = 1 To NumBlocks
' Reads a chunk and writes it to output file.
FileData = T(sField).GetChunk((i - 1) * BlockSize _
+ LeftOver, BlockSize)
Put DestFile, , FileData
RetVal = SysCmd(acSysCmdUpdateMeter, _
((i - 1) * BlockSize + LeftOver) / 1000)
Next i
' Terminates function
RetVal = SysCmd(acSysCmdRemoveMeter)
Close DestFile
WriteBLOB = FileLength
Exit Function
Err_WriteBLOB:
WriteBLOB = -Err
Exit Function
End Function |
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