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<?php
/**
* PHP Reader Library
*
* Copyright (c) 2006-2008 The PHP Reader Project Workgroup. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* - Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* - Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* - Neither the name of the project workgroup nor the names of its
* contributors may be used to endorse or promote products derived from this
* software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* @package php-reader
* @copyright Copyright (c) 2006-2008 PHP Reader Project Workgroup
* @license http://code.google.com/p/php-reader/wiki/License New BSD License
* @version $Id: Magic.php 73 2008-04-12 19:07:31Z svollbehr $
*/
/**#@+ @ignore */
require_once("Reader.php");
/**#@-*/
/**
* This class is used to classify the given file using some magic bytes
* characteristic to a particular file type. The classification information can
* be a MIME type or just text describing the file.
*
* This method is slower than determining the type by file suffix but on the
* other hand reduces the risk of fail positives during the test.
*
* The magic file consists of ASCII characters defining the magic numbers for
* different file types. Each row has 4 to 5 columns, empty and commented lines
* (those starting with a hash character) are ignored. Columns are described
* below.
*
* o <b>1</b> -- byte number to begin checking from. ">" indicates a dependency
* upon the previous non-">" line
* o <b>2</b> -- type of data to match. Can be one of following
* - <i>byte</i> (single character)
* - <i>short</i> (machine-order 16-bit integer)
* - <i>long</i> (machine-order 32-bit integer)
* - <i>string</i> (arbitrary-length string)
* - <i>date</i> (long integer date (seconds since Unix epoch/1970))
* - <i>beshort</i> (big-endian 16-bit integer)
* - <i>belong</i> (big-endian 32-bit integer)
* - <i>bedate</i> (big-endian 32-bit integer date)
* - <i>leshort</i> (little-endian 16-bit integer)
* - <i>lelong</i> (little-endian 32-bit integer)
* - <i>ledate</i> (little-endian 32-bit integer date)
* o <b>3</b> -- contents of data to match
* o <b>4</b> -- file description/MIME type if matched
* o <b>5</b> -- optional MIME encoding if matched and if above was a MIME type
*
* @package php-reader
* @author Sven Vollbehr <svollbehr@gmail.com>
* @copyright Copyright (c) 2006-2008 PHP Reader Project Workgroup
* @license http://code.google.com/p/php-reader/wiki/License New BSD License
* @version $Rev: 73 $
*/
final class Magic
{
/** @var string */
private $_magic;
/**
* Reads the magic information from given magic file.
*
* @param string $filename The path to the magic file.
*/
public function __construct($filename)
{
$reader = new Reader($filename);
$this->_magic = $reader->read($reader->getSize());
}
/**
* Returns the recognized MIME type/description of the given file. The type
* is determined by the content using magic bytes characteristic for the
* particular file type.
*
* If the type could not be found, the function returns the default value, or
* <var>false</var>.
*
* @param string $filename The file path whose type to determine.
* @param string $default The default value.
* @return string|false
*/
public function getType($filename, $default = false)
{
$reader = new Reader($filename);
$parentOffset = 0;
foreach (preg_split("/^/m", $this->_magic) as $line) {
$chunks = array();
if (!preg_match("/^(?P<Dependant>>?)(?P<Byte>\d+)\s+(?P<MatchType>\S+)" .
"\s+(?P<MatchData>\S+)(?:\s+(?P<MIMEType>[a-z]+\/[a-z-" .
"0-9]+)?(?:\s+(?P<Description>.+))?)?$/", $line, $chunks))
continue;
if ($chunks["Dependant"]) {
$reader->setOffset($parentOffset);
$reader->skip($chunks["Byte"]);
} else
$reader->setOffset($parentOffset = $chunks["Byte"]);
$matchType = strtolower($chunks["MatchType"]);
$matchData = preg_replace
(array("/\\\\ /", "/\\\\\\\\/", "/\\\\([0-7]{1,3})/e",
"/\\\\x([0-9A-Fa-f]{1,2})/e", "/0x([0-9A-Fa-f]+)/e"),
array(" ", "\\\\", "pack(\"H*\", base_convert(\"$1\", 8, 16));",
"pack(\"H*\", \"$1\");", "hexdec(\"$1\");"),
$chunks["MatchData"]);
switch ($matchType) {
case "byte": // single character
$data = $reader->readInt8();
break;
case "short": // machine-order 16-bit integer
$data = $reader->readInt16();
break;
case "long": // machine-order 32-bit integer
$data = $reader->readInt32();
break;
case "string": // arbitrary-length string
$data = $reader->readString8(strlen($matchData));
break;
case "date": // long integer date (seconds since Unix epoch/1970)
$data = $reader->readInt64BE();
break;
case "beshort": // big-endian 16-bit integer
$data = $reader->readUInt16BE();
break;
case "belong": // big-endian 32-bit integer
case "bedate": // big-endian 32-bit integer date
$data = $reader->readUInt32BE();
break;
case "leshort": // little-endian 16-bit integer
$data = $reader->readUInt16LE();
break;
case "lelong": // little-endian 32-bit integer
case "ledate": // little-endian 32-bit integer date
$data = $reader->readUInt32LE();
break;
default:
$data = null;
break;
}
if (strcmp($data, $matchData) == 0) {
if (!empty($chunks["MIMEType"]))
return $chunks["MIMEType"];
if (!empty($chunks["Description"]))
return $chunks["Description"];
}
}
return $default;
}
}
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