(PowerShell) Compress Large Binary File in Blocks

Compresses a large binary file in blocks. This example uses BeginCompressBytes, MoreCompressBytes, and EndCompressBytes.

Chilkat .NET Downloads Chilkat .NET Assemblies

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

# This example assumes 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 large binary file for reading.
$success = $facSrc.OpenForRead("qa_data/bmp/big.bmp")
if ($success -ne $true) {
    $($facSrc.LastErrorText)
    exit
}

# If we compress in 64K chunks, find out how many blocks there will be.
$blockSize = 65536
$numBlocks = $facSrc.GetNumBlocks($blockSize)

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

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

$i = 0
while ($i -lt $numBlocks) {
    $fileBytes = $facSrc.ReadBlock($i,$blockSize)
    if ($i -eq 0) {
        $compressedBytes = $compress.BeginCompressBytes($fileBytes)
    }
    else {
        $compressedBytes = $compress.MoreCompressBytes($fileBytes)
    }

    $facDest.FileWrite($compressedBytes)

    $i = $i + 1
}

# At the very end, flush any remaining compressed bytes, if any.
$compressedBytes = $compress.EndCompressBytes()
$facDest.FileWrite($compressedBytes)

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

$("Finished compressing file.")