(PHP ActiveX) Compress Large Binary File in Blocks

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

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

// For versions of Chilkat < 10.0.0, use new COM('Chilkat_9_5_0.Chilkat.FileAccess')
$facSrc = new COM("Chilkat.FileAccess");
// For versions of Chilkat < 10.0.0, use new COM('Chilkat_9_5_0.Chilkat.FileAccess')
$facDest = new COM("Chilkat.FileAccess");

// Open a large binary file for reading.
$success = $facSrc->OpenForRead('qa_data/bmp/big.bmp');
if ($success != 1) {
    print $facSrc->LastErrorText . "\n";
    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 != 1) {
    print $facDest->LastErrorText . "\n";
    exit;
}

// For versions of Chilkat < 10.0.0, use new COM('Chilkat_9_5_0.Chilkat.Compression')
$compress = new COM("Chilkat.Compression");
$compress->Algorithm = 'deflate';

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

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

?>