(PHP ActiveX) Decompress Large Binary File in Blocks

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

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows Note: The php_com_dotnet.dll may need to be enabled inside of php.ini.

<?php

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

$facSrc = new COM("Chilkat_9_5_0.FileAccess");
$facDest = new COM("Chilkat_9_5_0.FileAccess");

// 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 . "\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 . "\n";
    exit;
}

$compress = new COM("Chilkat_9_5_0.Compression");
$compress->Algorithm = 'deflate';

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

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

?>