getid3_riff::ParseRIFF( int $startoffset, int $maxoffset ): array|false

Compatibility

Present in every tracked release (6.7.10 to 7.1.3), and compiles on PHP 7.4 through 8.6-dev.

Parameters

$startoffsetint

$maxoffsetint

Return value

array|false

Performance profile

How much work a call to getid3_riff::ParseRIFF() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.

Cost class

Moderate

Touches nothing outside its own arguments.

Scaling

Scales with input

The body loops, so the work grows with what you pass in.

Instructions

1460

Executed per call on PHP 8.5. The body compiles to 1460.

Plugin surface

None

Nothing here hands control to plugin code.

Called by

2

2 places in core call this, so the cost is paid more often than your own code shows.

Uses · 14

• getid3_riff::fseek()
• getid3_riff::ftell()
• getid3_riff::fread()
• getid3_riff::EitherEndian2Int()
• getid3_riff::error()
• getid3_riff::warning()
• getid3_lib::LittleEndian2Int()
• getid3_mp3::MPEGaudioHeaderBytesValid()
• getID3::__construct()
• getid3_mp3::__construct()
• getid3_ac3::__construct()
• getid3_riff::ParseRIFF()

Used by · 2

• getid3_riff::Analyze()
• getid3_riff::ParseRIFF()

Source code

View on Trac ↗View on GitHub ↗

1582	public function ParseRIFF($startoffset, $maxoffset) {1583		$info = &$this->getid3->info;1584 1585		$RIFFchunk = array();1586		$FoundAllChunksWeNeed = false;1587		$LISTchunkParent = null;1588		$LISTchunkMaxOffset = null;1589		$AC3syncwordBytes = pack('n', getid3_ac3::syncword); // 0x0B77 -> "\x0B\x77"1590 1591		try {1592			$this->fseek($startoffset);1593			$maxoffset = min($maxoffset, $info['avdataend']);1594			while ($this->ftell() < $maxoffset) {1595				$chunknamesize = $this->fread(8);1596				//$chunkname =                          substr($chunknamesize, 0, 4);1597				$chunkname = str_replace("\x00", '_', substr($chunknamesize, 0, 4));  // note: chunk names of 4 null bytes do appear to be legal (has been observed inside INFO and PRMI chunks, for example), but makes traversing array keys more difficult1598				$chunksize =  $this->EitherEndian2Int(substr($chunknamesize, 4, 4));1599				//if (strlen(trim($chunkname, "\x00")) < 4) {1600				if (strlen($chunkname) < 4) {1601					$this->error('Expecting chunk name at offset '.($this->ftell() - 8).' but found nothing. Aborting RIFF parsing.');1602					break;1603				}1604				if (($chunksize == 0) && ($chunkname != 'JUNK')) {1605					$this->warning('Chunk ('.$chunkname.') size at offset '.($this->ftell() - 4).' is zero. Aborting RIFF parsing.');1606					break;1607				}1608				if (($chunksize % 2) != 0) {1609					// all structures are packed on word boundaries1610					$chunksize++;1611				}1612 1613				switch ($chunkname) {1614					case 'LIST':1615						$listname = $this->fread(4);1616						if (preg_match('#^(movi|rec )$#i', $listname)) {1617							$RIFFchunk[$listname]['offset'] = $this->ftell() - 4;1618							$RIFFchunk[$listname]['size']   = $chunksize;1619 1620							if (!$FoundAllChunksWeNeed) {1621								$WhereWeWere      = $this->ftell();1622								$AudioChunkHeader = $this->fread(12);1623								$AudioChunkStreamNum  =                              substr($AudioChunkHeader, 0, 2);1624								$AudioChunkStreamType =                              substr($AudioChunkHeader, 2, 2);1625								$AudioChunkSize       = getid3_lib::LittleEndian2Int(substr($AudioChunkHeader, 4, 4));1626 1627								if ($AudioChunkStreamType == 'wb') {1628									$FirstFourBytes = substr($AudioChunkHeader, 8, 4);1629									if (preg_match('/^\xFF[\xE2-\xE7\xF2-\xF7\xFA-\xFF][\x00-\xEB]/s', $FirstFourBytes)) {1630										// MP31631										if (getid3_mp3::MPEGaudioHeaderBytesValid($FirstFourBytes)) {1632											$getid3_temp = new getID3();1633											$getid3_temp->openfile($this->getid3->filename, $this->getid3->info['filesize'], $this->getid3->fp);1634											$getid3_temp->info['avdataoffset'] = $this->ftell() - 4;1635											$getid3_temp->info['avdataend']    = $this->ftell() + $AudioChunkSize;1636											$getid3_mp3 = new getid3_mp3($getid3_temp, __CLASS__);1637											$getid3_mp3->getOnlyMPEGaudioInfo($getid3_temp->info['avdataoffset'], false);1638											if (isset($getid3_temp->info['mpeg']['audio'])) {1639												$info['mpeg']['audio']         = $getid3_temp->info['mpeg']['audio'];1640												$info['audio']                 = $getid3_temp->info['audio'];1641												$info['audio']['dataformat']   = 'mp'.$info['mpeg']['audio']['layer'];1642												$info['audio']['sample_rate']  = $info['mpeg']['audio']['sample_rate'];1643												$info['audio']['channels']     = $info['mpeg']['audio']['channels'];1644												$info['audio']['bitrate']      = $info['mpeg']['audio']['bitrate'];1645												$info['audio']['bitrate_mode'] = strtolower($info['mpeg']['audio']['bitrate_mode']);1646												//$info['bitrate']               = $info['audio']['bitrate'];1647											}1648											unset($getid3_temp, $getid3_mp3);1649										}1650 1651									} elseif (strpos($FirstFourBytes, $AC3syncwordBytes) === 0) {1652										// AC31653										$getid3_temp = new getID3();1654										$getid3_temp->openfile($this->getid3->filename, $this->getid3->info['filesize'], $this->getid3->fp);1655										$getid3_temp->info['avdataoffset'] = $this->ftell() - 4;1656										$getid3_temp->info['avdataend']    = $this->ftell() + $AudioChunkSize;1657										$getid3_ac3 = new getid3_ac3($getid3_temp);1658										$getid3_ac3->Analyze();1659										if (empty($getid3_temp->info['error'])) {1660											$info['audio']   = $getid3_temp->info['audio'];1661											$info['ac3']     = $getid3_temp->info['ac3'];

Changelog

Unchanged from 6.7.10 through 7.1.3.

1. 6.7.10
2. 6.8.11
3. 6.9.10
4. 7.0.7
5. 7.1.3

Signature, return type and hooks compared across 5 parsed releases.

About this page

Parsed data

Generated from the wordpress-develop 6.8.11 tag, from src/wp-includes/ID3/module.audio-video.riff.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.

Corrections

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