mbirth/php-mp3info
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Optimise id3v2 header parsing

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This commit is contained in:
Markus Birth 2024-05-27 20:04:23 +01:00
parent d474f40403
commit 37bc9d5ec6
1 changed files with 44 additions and 34 deletions
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78
src/Mp3Info.php
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@ -166,11 +166,13 @@ class Mp3Info
* @var int Major version of id3v2 tag (if id3v2 present) (2 or 3 or 4)
*/
public $id3v2MajorVersion;
public $id3v2Version;
/**
* @var int Minor version of id3v2 tag (if id3v2 present)
*/
public $id3v2MinorVersion;
public $id3v2Revision;
/**
* @var array List of id3v2 header flags (if id3v2 present)
@ -501,45 +503,53 @@ class Mp3Info
private function readId3v2Body()
{
// read the rest of the id3v2 header
$raw = $this->fileObj->getBytes(7);
$data = unpack('Cmajor_version/Cminor_version/Cflags/C4size', $raw);
$this->id3v2MajorVersion = $data['major_version'];
$this->id3v2MinorVersion = $data['minor_version'];
$flags = decbin($data['flags']);
if ($this->id3v2MajorVersion == 2) { // parse id3v2.2.0 header flags
$this->id3v2Flags = array(
'unsynchronisation' => (bool)substr($flags, 0, 1),
'compression' => (bool)substr($flags, 1, 1),
);
} else if ($this->id3v2MajorVersion == 3) { // parse id3v2.3.0 header flags
$this->id3v2Flags = array(
'unsynchronisation' => (bool)substr($flags, 0, 1),
'extended_header' => (bool)substr($flags, 1, 1),
'experimental_indicator' => (bool)substr($flags, 2, 1),
);
if ($this->id3v2Flags['extended_header'])
throw new \Exception('NEED TO PARSE EXTENDED HEADER!');
} else if ($this->id3v2MajorVersion == 4) { // parse id3v2.4.0 header flags
$this->id3v2Flags = array(
'unsynchronisation' => (bool)substr($flags, 0, 1),
'extended_header' => (bool)substr($flags, 1, 1),
'experimental_indicator' => (bool)substr($flags, 2, 1),
'footer_present' => (bool)substr($flags, 3, 1),
);
if ($this->id3v2Flags['extended_header'])
throw new \Exception('NEED TO PARSE EXTENDED HEADER!');
if ($this->id3v2Flags['footer_present'])
throw new \Exception('NEED TO PARSE id3v2.4 FOOTER!');
}
$size = $data['size1'] << 21 | $data['size2'] << 14 | $data['size3'] << 7 | $data['size4'];
$raw = $this->fileObj->getBytes(3);
$data = unpack('Cversion/Crevision/Cflags', $raw);
$this->id3v2Version = $data['version'];
$this->id3v2Revision = $data['revision'];
// backwards compatibility:
$this->id3v2MajorVersion = $data['version'];
$this->id3v2MinorVersion = $data['revision'];
if ($this->id3v2MajorVersion == 2) {
$flags = str_pad(decbin($data['flags']), 8, '0', STR_PAD_LEFT);
$this->id3v2Flags = array();
if ($this->id3v2Version >= 2) {
// parse id3v2.2.0 header flags
$this->id3v2Flags['unsynchronisation'] = (bool)substr($flags, 0, 1);
$this->id3v2Flags['compression'] = (bool)substr($flags, 1, 1);
}
if ($this->id3v2Version >= 3) {
// id3v2.3 changes second bit from compression to extended_header
$this->id3v2Flags['extended_header'] = &$this->id3v2Flags['compression'];
unset($this->id3v2Flags['compression']);
// parse additional id3v2.3.0 header flags
$this->id3v2Flags['experimental_indicator'] = (bool)substr($flags, 2, 1);
if ($this->id3v2Flags['extended_header']) {
throw new Exception('NEED TO PARSE EXTENDED HEADER!');
}
}
if ($this->id3v2Version >= 4) {
// parse additional id3v2.4.0 header flags
$this->id3v2Flags['footer_present'] = (bool)substr($flags, 3, 1);
if ($this->id3v2Flags['footer_present']) {
throw new Exception('NEED TO PARSE id3v2.4 FOOTER!');
}
}
$size = $this->getSyncsafeSize($this->fileObj->getBytes(4));
if ($this->id3v2Version == 2) {
// parse id3v2.2.0 body
/*throw new \Exception('NEED TO PARSE id3v2.2.0 flags!');*/
} elseif ($this->id3v2MajorVersion == 3) {
} elseif ($this->id3v2Version == 3) {
// parse id3v2.3.0 body
$this->parseId3v23Body(10 + $size);
} elseif ($this->id3v2MajorVersion == 4) {
} elseif ($this->id3v2Version == 4) {
// parse id3v2.4.0 body
$this->parseId3v24Body(10 + $size);
}