(PowerShell) Decompress Large Binary File in Blocks

Decompresses a large binary file in blocks. This example uses BeginDecompressBytes, MoreDecompressBytes, and EndDecompressBytes.

Chilkat .NET Downloads Chilkat .NET Assemblies

Add-Type -Path "C:\chilkat\ChilkatDotNet47-9.5.0-x64\ChilkatDotNet47.dll"

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

$facSrc = New-Object Chilkat.FileAccess
$facDest = New-Object Chilkat.FileAccess

# Open a previously compressed file for decompressing.
# See Compress Large File in Blocks

$success = $facSrc.OpenForRead("qa_data/bmp/compressedBmp.dat")
if ($success -ne $true) {
    $($facSrc.LastErrorText)
    exit
}

# If we compress in 32K chunks, find out how many blocks there will be.
$blockSize = 32768
$numBlocks = $facSrc.GetNumBlocks($blockSize)

# Open an output file for the decompressed data.
$success = $facDest.OpenForWrite("qa_output/decompressed.bmp")
if ($success -ne $true) {
    $($facDest.LastErrorText)
    exit
}

$compress = New-Object Chilkat.Compression
$compress.Algorithm = "deflate"

$i = 0
while ($i -lt $numBlocks) {
    $compressedBytes = $facSrc.ReadBlock($i,$blockSize)
    if ($i -eq 0) {
        $decompressedBytes = $compress.BeginDecompressBytes($compressedBytes)
    }
    else {
        $decompressedBytes = $compress.MoreDecompressBytes($compressedBytes)
    }

    $facDest.FileWrite($decompressedBytes)

    $i = $i + 1
}

# At the very end, flush any remaining decompressed bytes, if any.
$decompressedBytes = $compress.EndDecompressBytes()
$facDest.FileWrite($decompressedBytes)

$facSrc.FileClose()
$facDest.FileClose()

$("Finished decompressing file.")