(Perl) Decompress Large Binary File in Blocks

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

Chilkat Perl Downloads Perl Module for Windows, MacOS, Linux, Alpine Linux

use chilkat();

# 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 = $facSrc->OpenForRead("qa_data/bmp/compressedBmp.dat");
if ($success != 1) {
    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 = $facDest->OpenForWrite("qa_output/decompressed.bmp");
if ($success != 1) {
    print $facDest->lastErrorText() . "\r\n";
    exit;
}

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

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

$i = 0;
while ($i < $numBlocks) {
    $success = $facSrc->ReadBlock($i,$blockSize,$compressedBytes);
    if ($i == 0) {
        $success = $compress->BeginDecompressBytes($compressedBytes,$decompressedBytes);
    }
    else {
        $success = $compress->MoreDecompressBytes($compressedBytes,$decompressedBytes);
    }

    $facDest->FileWrite($decompressedBytes);

    $i = $i + 1;
}

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

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

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