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<?php
/**
* This file is part of FPDI
*
* @package setasign\Fpdi
* @copyright Copyright (c) 2020 Setasign GmbH & Co. KG (https://www.setasign.com)
* @license http://opensource.org/licenses/mit-license The MIT License
*/
namespace setasign\Fpdi\PdfParser\Filter;
/**
* Class for handling zlib/deflate encoded data
*/
class Flate implements FilterInterface
{
/**
* Checks whether the zlib extension is loaded.
*
* Used for testing purpose.
*
* @return boolean
* @internal
*/
protected function extensionLoaded()
{
return \extension_loaded('zlib');
}
/**
* Decodes a flate compressed string.
*
* @param string|false $data The input string
* @return string
* @throws FlateException
*/
public function decode($data)
{
if ($this->extensionLoaded()) {
$oData = $data;
$data = (($data !== '') ? @\gzuncompress($data) : '');
if ($data === false) {
// let's try if the checksum is CRC32
$fh = fopen('php://temp', 'w+b');
fwrite($fh, "\x1f\x8b\x08\x00\x00\x00\x00\x00" . $oData);
stream_filter_append($fh, 'zlib.inflate', STREAM_FILTER_READ, ['window' => 30]);
fseek($fh, 0);
$data = @stream_get_contents($fh);
fclose($fh);
if ($data) {
return $data;
}
// Try this fallback
$tries = 0;
$oDataLen = strlen($oData);
while ($tries < 6 && ($data === false || (strlen($data) < ($oDataLen - $tries - 1)))) {
$data = @(gzinflate(substr($oData, $tries)));
$tries++;
}
// let's use this fallback only if the $data is longer than the original data
if (strlen($data) > ($oDataLen - $tries - 1)) {
return $data;
}
if (!$data) {
throw new FlateException(
'Error while decompressing stream.',
FlateException::DECOMPRESS_ERROR
);
}
}
} else {
throw new FlateException(
'To handle FlateDecode filter, enable zlib support in PHP.',
FlateException::NO_ZLIB
);
}
return $data;
}
}
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