(AutoIt) Decompress Large Text File in Blocks

Decompresses a large text file in blocks, and compares the restored (decompressed) file with the original to make sure it's correct.

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

; This example requires the Chilkat API to have been previously unlocked.
; See Global Unlock Sample for sample code.

; First, let's compress a text file.
; We'll then decompress in blocks, and compare the decompressed with the original file.

; Compress a text file:
$oCompress = ObjCreate("Chilkat_9_5_0.Compression")
$oCompress.Algorithm = "deflate"

Local $bSuccess = $oCompress.CompressFile("qa_data/hamlet.xml","qa_data/hamlet_compressed.dat")
If ($bSuccess <> True) Then
    ConsoleWrite($oCompress.LastErrorText & @CRLF)
    Exit
EndIf

$oFac = ObjCreate("Chilkat_9_5_0.FileAccess")

; Examine the uncompressed and compressed sizes:
Local $sOriginalPath = "qa_data/hamlet.xml"
; Note: The FileSize method returns a signed 32-bit integer.  If the file is potentially larger than 2GB, call FileSizeStr instead to return
; the size of the file as a string, then convert to an integer value.
ConsoleWrite("uncompressed size: " & $oFac.FileSize($sOriginalPath) & @CRLF)
ConsoleWrite("compressed size: " & $oFac.FileSize("qa_data/hamlet_compressed.dat") & @CRLF)

; Decompress in blocks..
$oFacSrc = ObjCreate("Chilkat_9_5_0.FileAccess")
$oFacDest = ObjCreate("Chilkat_9_5_0.FileAccess")

$oFacSrc.OpenForRead("qa_data/hamlet_compressed.dat")

; If we compress in 32K chunks, find out how many blocks there will be.
Local $iBlockSize = 32768
Local $iNumBlocks = $oFacSrc.GetNumBlocks($iBlockSize)

; Open an output file for the decompressed data.
Local $sRestoredPath = "qa_output/hamlet_restored.xml"
$bSuccess = $oFacDest.OpenForWrite($sRestoredPath)
If ($bSuccess <> True) Then
    ConsoleWrite($oFacDest.LastErrorText & @CRLF)
    Exit
EndIf

Local $sDecompressedStr
Local $oCompressedBytes

Local $i = 0
While $i < $iNumBlocks
    $oCompressedBytes = $oFacSrc.ReadBlock($i,$iBlockSize)
    If ($i = 0) Then
        $sDecompressedStr = $oCompress.BeginDecompressString($oCompressedBytes)
    Else
        $sDecompressedStr = $oCompress.MoreDecompressString($oCompressedBytes)
    EndIf

    $oFacDest.AppendText($sDecompressedStr,"utf-8")

    $i = $i + 1
Wend

; At the very end, flush any remaining content, if any.
$sDecompressedStr = $oCompress.EndDecompressString()
$oFacDest.AppendText($sDecompressedStr,"utf-8")

$oFacSrc.FileClose 
$oFacDest.FileClose 

; Examine the size of the restored file.
ConsoleWrite("restored size: " & $oFac.FileSize($sRestoredPath) & @CRLF)

; Compare the contents of the original with the restored.
Local $bEqualContents = $oFac.FileContentsEqual($sRestoredPath,$sOriginalPath)
ConsoleWrite("Contents Equal: " & $bEqualContents & @CRLF)