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

Compatibility

Present in every tracked release (6.7.7 to 7.1.0), 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

Light

Touches nothing outside its own arguments.

Scaling

Scales with input

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

Instructions

64

Executed per call on PHP 8.5. The body compiles to 1481.

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.

What one call costs · 1 distinct outcome

One number would be a lie: the work depends on which branch runs. These are every distinct cost getid3_riff::ParseRIFF() can have, taken from its control-flow graph on PHP 8.5.

This body has more branch combinations than are worth enumerating, so the table covers the outcomes found first rather than every one that exists.

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 ↗

1592	public function ParseRIFF($startoffset, $maxoffset) {1593		$info = &$this->getid3->info;1594 1595		$RIFFchunk = array();1596		$FoundAllChunksWeNeed = false;1597		$LISTchunkParent = null;1598		$LISTchunkMaxOffset = null;1599		$AC3syncwordBytes = pack('n', getid3_ac3::syncword); // 0x0B77 -> "\x0B\x77"1600 1601		try {1602			$this->fseek($startoffset);1603			$maxoffset = min($maxoffset, $info['avdataend']);1604			while ($this->ftell() < $maxoffset) {1605				$chunknamesize = $this->fread(8);1606				//$chunkname =                          substr($chunknamesize, 0, 4);1607				$chunkname = str_replace("\x00", '_', substr($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 difficult1608				$chunksize =  $this->EitherEndian2Int(substr($chunknamesize, 4, 4));1609				//if (strlen(trim($chunkname, "\x00")) < 4) {1610				if (strlen($chunkname) < 4) {1611					$this->error('Expecting chunk name at offset '.($this->ftell() - 8).' but found nothing. Aborting RIFF parsing.');1612					break;1613				}1614				if ($chunksize == 0) {1615					if ($chunkname == 'JUNK') {1616						// this is allowed1617					} elseif ($chunkname == 'data') {1618						// https://github.com/JamesHeinrich/getID3/issues/4681619						// may occur in streaming files where the data size is unknown1620						$chunksize = $info['avdataend'] - $this->ftell();1621						$this->warning('RIFF.data size field is empty, assuming the correct value is filesize-offset ('.$chunksize.')');1622					} else {1623						$this->warning('Chunk ('.$chunkname.') size at offset '.($this->ftell() - 4).' is zero. Aborting RIFF parsing.');1624						break;1625					}1626				}1627				if (($chunksize % 2) != 0) {1628					// all structures are packed on word boundaries1629					$chunksize++;1630				}1631 1632				switch ($chunkname) {1633					case 'LIST':1634						$listname = $this->fread(4);1635						if (preg_match('#^(movi|rec )$#i', $listname)) {1636							$RIFFchunk[$listname]['offset'] = $this->ftell() - 4;1637							$RIFFchunk[$listname]['size']   = $chunksize;1638 1639							if (!$FoundAllChunksWeNeed) {1640								$WhereWeWere      = $this->ftell();1641								$AudioChunkHeader = $this->fread(12);1642								$AudioChunkStreamNum  =                              substr($AudioChunkHeader, 0, 2);1643								$AudioChunkStreamType =                              substr($AudioChunkHeader, 2, 2);1644								$AudioChunkSize       = getid3_lib::LittleEndian2Int(substr($AudioChunkHeader, 4, 4));1645 1646								if ($AudioChunkStreamType == 'wb') {1647									$FirstFourBytes = substr($AudioChunkHeader, 8, 4);1648									if (preg_match('/^\xFF[\xE2-\xE7\xF2-\xF7\xFA-\xFF][\x00-\xEB]/s', $FirstFourBytes)) {1649										// MP31650										if (getid3_mp3::MPEGaudioHeaderBytesValid($FirstFourBytes)) {1651											$getid3_temp = new getID3();1652											$getid3_temp->openfile($this->getid3->filename, $this->getid3->info['filesize'], $this->getid3->fp);1653											$getid3_temp->info['avdataoffset'] = $this->ftell() - 4;1654											$getid3_temp->info['avdataend']    = $this->ftell() + $AudioChunkSize;1655											$getid3_mp3 = new getid3_mp3($getid3_temp, __CLASS__);1656											$getid3_mp3->getOnlyMPEGaudioInfo($getid3_temp->info['avdataoffset'], false);1657											if (isset($getid3_temp->info['mpeg']['audio'])) {1658												$info['mpeg']['audio']         = $getid3_temp->info['mpeg']['audio'];1659												$info['audio']                 = $getid3_temp->info['audio'];1660												$info['audio']['dataformat']   = 'mp'.$info['mpeg']['audio']['layer'];1661												$info['audio']['sample_rate']  = $info['mpeg']['audio']['sample_rate'];1662												$info['audio']['channels']     = $info['mpeg']['audio']['channels'];1663												$info['audio']['bitrate']      = $info['mpeg']['audio']['bitrate'];1664												$info['audio']['bitrate_mode'] = strtolower($info['mpeg']['audio']['bitrate_mode']);1665												//$info['bitrate']               = $info['audio']['bitrate'];1666											}1667											unset($getid3_temp, $getid3_mp3);1668										}1669 1670									} elseif (strpos($FirstFourBytes, $AC3syncwordBytes) === 0) {1671										// AC3

Changelog

Unchanged from 6.7.7 through 7.1.0.

1. 6.7.7
2. 6.8.8
3. 6.9.7
4. 7.0.4
5. 7.1.0

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

About this page

Parsed data

Generated from the wordpress-develop 7.1.0 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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