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Added Reader.
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@rhorber
rhorber committed Oct 21, 2018
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<?php

/**
* Class Reader.
*
* @package Rhorber\ID3rw
* @author Raphael Horber
* @version 21.10.2018
*/
namespace Rhorber\ID3rw;


/**
* Class for reading the ID3 tag (and its frames) of a file (currently only v2.4.0).
*
* - {@link __construct}: Opens the passed file and reads the tag (with its frames).
* - {@link getFrames}: Returns the parsed frames.
* - {@link getTagSize}: Returns the total size of the tag (excluding header, including padding).
* - {@link _parseHeader}: Parses the ID3 header.
* - {@link _parseFrames}: Parses the ID3 frames.
*
* @package Rhorber\ID3rw
* @author Raphael Horber
* @version 21.10.2018
*/
class Reader
{
/**
* Handle of the source file.
*
* @access private
* @var resource
*/
private $_fileHandle;

/**
* Major version of the source file (4).
*
* @access private
* @var integer
*/
private $_version;

/**
* Total size of the tag (excluding header, including padding).
*
* @access private
* @var integer
*/
private $_tagSize;

/**
* Parsed frames of the tag.
*
* @access private
* @var array[]
*/
private $_frames;


/**
* Constructor: Opens the passed file and reads the tag (with its frames).
*
* @param string $filename Name of the file to read (optionally with path).
*
* @throws \InvalidArgumentException If the file could not be opened.
* @throws \UnexpectedValueException If the file does not contain a valid ID3 tag.
* @throws \UnexpectedValueException If the tag does contain unsupported features (wrong version, flags).
* @access public
* @author Raphael Horber
* @version 21.10.2018
*/
public function __construct(string $filename)
{
$this->_fileHandle = @fopen($filename, "rb");
if ($this->_fileHandle === false) {
throw new \InvalidArgumentException("File could not be opened!");
}
// declare(encoding="UTF-8");

$this->_parseHeader();
$this->parseFrames();

fclose($this->_fileHandle);
}

/**
* Returns the parsed frames.
*
* Format:
* <code>
* [
* 'identifier' => 'Four character identifier of the frame',
* 'content' => 'Text frames only, parsed content',
* 'encoding' => 'Text frames only, text encoding of content',
* 'raw' => 'RAW content of the frame (binary)',
* ]
* </code>
*
* @return array[]
* @access public
* @author Raphael Horber
* @version 21.10.2018
*/
public function getFrames(): array
{
return $this->_frames;
}

/**
* Returns the total size of the tag (excluding header, including padding).
*
* @return integer
* @access public
* @author Raphael Horber
* @version 21.10.2018
*/
public function getTagSize(): int
{
return $this->_tagSize;
}

/**
* Parses the ID3 header.
*
* @return void
* @throws \UnexpectedValueException If the file does not contain a valid ID3 tag.
* @throws \UnexpectedValueException If the tag does contain unsupported features (wrong version, flags).
* @access private
* @author Raphael Horber
* @version 21.10.2018
*/
private function _parseHeader()
{
$header = fread($this->_fileHandle, 10);
if ($header === false || strlen($header) !== 10) {
throw new \UnexpectedValueException("Could not read ID3 header!");
}

$identifier = substr($header, 0, 3);
$version = substr($header, 3, 2);
$tagFlags = substr($header, 5, 1);
$tagSize = substr($header, 6, 4);

if ($identifier !== "ID3") {
throw new \UnexpectedValueException("File does not contain ID3 header!");
}

// TODO: Support/Implement Version 2.3.0.
if ($version === "\x04\x00") {
$this->_version = 4;
// } elseif ($version === "\x03\x00") {
// $this->version = 3;
} else {
throw new \UnexpectedValueException("Unsupported version, got: ".bin2hex($version));
}

if ($tagFlags !== "\x00") {
throw new \UnexpectedValueException("Unsupported header flags, got: ".$tagFlags);
}

$this->_tagSize = Helpers::removeSynchSafeBits($tagSize);
}

/**
* Parses the ID3 frames.
*
* @return void
* @throws \UnexpectedValueException If the file does not contain a valid ID3 tag.
* @throws \UnexpectedValueException If the tag does contain unsupported features (flags, encoding, BOM).
* @access private
* @author Raphael Horber
* @version 21.10.2018
*/
private function parseFrames()
{
$frames = fread($this->_fileHandle, $this->_tagSize);

$stringToParse = $frames;
while (strlen($stringToParse) > 0) {
$header = substr($stringToParse, 0, 10);

if (substr($header, 0, 1) === "\x00") {
// Padding reached: End loop.
$stringToParse = "";
continue;
}

$identifier = substr($header, 0, 4);
$frameSize = substr($header, 4, 4);
$frameFlags = substr($header, 8, 2);

if ($frameFlags !== "\x00\x00") {
throw new \UnexpectedValueException("Unsupported frame flags, got: ".bin2hex($frameFlags));
}

if ($this->_version === 4) {
$frameSize = Helpers::removeSynchSafeBits($frameSize);
} else {
$frameSize = hexdec(bin2hex($frameSize));
}

$rawContent = substr($stringToParse, 10, $frameSize);

// TODO: Improve/Add parsing of other frames than "text".
// TODO: Text frames: Support multiple strings (v2.4.0).
if ($identifier{0} === "T") {
$encodingCode = substr($rawContent, 0, 1);
$content = substr($rawContent, 1);
switch ($encodingCode) {
case "\x00":
$encodingName = "ISO-8859-1";
// $delimiter = "\x00";
break;

case "\x01":
$bom = substr($content, 0, 2);
if ($bom === "\xff\xfe") {
$encodingName = "UTF-16LE";
} elseif ($bom === "\xfe\xff") {
$encodingName = "UTF-16BE";
} else {
throw new \UnexpectedValueException("Invalid BOM, got: ".bin2hex($bom));
}

$content = substr($content, 2);
// $delimiter = "\x00\x00";
break;

case "\x02":
$encodingName = "UTF-16BE";
// $delimiter = "\x00\x00";
break;

case "\x03":
$encodingName = "UTF-8";
// $delimiter = "\x00";
break;


default:
throw new \UnexpectedValueException("Invalid text encoding, got: ".bin2hex($encodingCode));
}
/*
$delimiterLength = (-1) * strlen($delimiter);
while (substr($content, $delimiterLength) === $delimiter) {
$content = substr($content, 0, $delimiterLength);
}
*/
$encoding = $encodingName;
} else {
$content = null;
$encoding = null;
}

$this->_frames[$identifier] = [
'identifier' => $identifier,
'content' => $content,
'encoding' => $encoding,
'raw' => $rawContent,
];

// Frame header + frame size.
$totalFrameSize = 10 + $frameSize;
$stringToParse = substr($stringToParse, $totalFrameSize);
}
}
}


// Útƒ-8 encoded

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