(PHP ActiveX) Compress and Decompress Hex String

Imagine we have data represented as a hex string. This example demonstrates how to decode, compress, and re-encode to a smaller hex string representing the compressed data. An even better choice is to re-encode to a more compact encoding such as base64.

Note: This example requires Chilkat v9.5.0.66 or greater.

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.

$strHex = '54686520717569636B2062726F776E20666F78206A756D706564206F76657220746865206C617A7920646F672E0D0A54686520717569636B2062726F776E20666F78206A756D706564206F76657220746865206C617A7920646F672E0D0A54686520717569636B2062726F776E20666F78206A756D706564206F76657220746865206C617A7920646F672E0D0A54686520717569636B2062726F776E20666F78206A756D706564206F76657220746865206C617A7920646F672E0D0A54686520717569636B2062726F776E20666F78206A756D706564206F76657220746865206C617A7920646F672E0D0A0D0A';

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

// For versions of Chilkat < 10.0.0, use new COM('Chilkat_9_5_0.Chilkat.BinData')
$binDat = new COM("Chilkat.BinData");
// Load the hex string into a BinData object.
// This decodes the hexidecimal. The decoded bytes will be contained in the BinData.
$binDat->AppendEncoded($strHex,'hex');

// Compress the BinData.
$compress->CompressBd($binDat);

// Get the compressed data in hex format:
$compressedHex = $binDat->getEncoded('hex');
print 'compressed hex:' . "\n";
print $compressedHex . "\n";

// The compressed hex is: 0BC94855282CCD4CCE56482ACA2FCF5348CBAF50C82ACD2D484D51C82F4B2D522801CAE72456552AA4E4A7EBF172850C61E5BC5C00

// Even better, get the compressed data in base64 format:
// (base64url and modbase64 are other valid choices...)
$compressedBase64 = $binDat->getEncoded('base64');
print 'compressed base64:' . "\n";
print $compressedBase64 . "\n";

// The compressed base64 is: C8lIVSgszUzOVkgqyi/PU0jLr1DIKs0tSE1RyC9LLVIoAcrnJFZVKqTkp+vxcoUMYeW8XAA=

// Now decompress:
$binDat->Clear();
$binDat->AppendEncoded($compressedHex,'hex');
$compress->DecompressBd($binDat);

$decompressedHex = $binDat->getEncoded('hex');
print 'decompressed hex:' . "\n";
print $decompressedHex . "\n";

// The output is the original hex string:
// 54686520717569636B2062726F776E20666F78206A756D706564206F76657220746865206C617A7920646F672E0D0A54686520717569636B2062726F776E20666F78206A756D706564206F76657220746865206C617A7920646F672E0D0A54686520717569636B2062726F776E20666F78206A756D706564206F76657220746865206C617A7920646F672E0D0A54686520717569636B2062726F776E20666F78206A756D706564206F76657220746865206C617A7920646F672E0D0A54686520717569636B2062726F776E20666F78206A756D706564206F76657220746865206C617A7920646F672E0D0A0D0A

?>