(PHP Extension) Decompress Large Binary File in Blocks

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

Chilkat PHP Downloads PHP Extension for Windows, Linux, MacOS, Alpine Linux, Solaris

<?php

// The version number (9_5_0) should match version of the Chilkat extension used, omitting the micro-version number.
// For example, if using Chilkat v9.5.0.48, then include as shown here:
include("chilkat_9_5_0.php");

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

$facSrc = new CkFileAccess();
$facDest = new CkFileAccess();

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

$success = $facSrc->OpenForRead('qa_data/bmp/compressedBmp.dat');
if ($success != true) {
    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 != true) {
    print $facDest->lastErrorText() . "\n";
    exit;
}

$compress = new CkCompression();
$compress->put_Algorithm('deflate');

$decompressedBytes = new CkByteData();
$compressedBytes = new CkByteData();

$i = 0;
while ($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.' . "\n";

?>