Perl Requires Chilkat v11.0.0+

Decompress Large Binary File in Blocks

See more Compression Examples

Decompresses a large binary file in blocks. Perl

use chilkat();

$success = 0;

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

$facSrc = chilkat::CkFileAccess->new();
$facDest = chilkat::CkFileAccess->new();

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

$success = $facSrc->OpenForRead("c:/temp/qa_output/compressedBmp.dat");
if ($success == 0) {
    print $facSrc->lastErrorText() . "\r\n";
    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 = $facDest->OpenForWrite("c:/temp/qa_output/decompressed.bmp");
if ($success == 0) {
    print $facDest->lastErrorText() . "\r\n";
    exit;
}

$compress = chilkat::CkCompression->new();
$compress->put_Algorithm("deflate");

$decompressedBytes = chilkat::CkByteData->new();
$compressedBytes = chilkat::CkByteData->new();

#  Assuming numBlocks > 1
$compress->put_FirstChunk(1);
$compress->put_LastChunk(0);

$i = 0;
while ($i < $numBlocks) {
    $success = $facSrc->ReadBlock($i,$blockSize,$compressedBytes);

    $success = $compress->DecompressBytes($compressedBytes,$decompressedBytes);
    $facDest->FileWrite($decompressedBytes);

    $i = $i + 1;

    $compress->put_FirstChunk(0);
    if ($i == ($numBlocks - 1)) {
        $compress->put_LastChunk(1);
    }

}

$facSrc->FileClose();
$facDest->FileClose();

print "Finished decompressing file." . "\r\n";