getid3_ogg::ParseVorbisComments(): bool

Compatibility

Present in every tracked release (6.7.7 to 7.1.0), and compiles on PHP 7.4 through 8.6-dev.

Return value

bool

Performance profile

How much work a call to getid3_ogg::ParseVorbisComments() 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 how much data it finds.

Instructions

13–203

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 540.

Plugin surface

None

Nothing here hands control to plugin code.

Called by

1

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

What one call costs · 11 distinct outcomes

One number would be a lie: the work depends on which branch runs. These are every distinct cost getid3_ogg::ParseVorbisComments() 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 · 11

• getid3_ogg::ftell()
• getid3_ogg::fseek()
• getid3_ogg::fread()
• getid3_ogg::OggPageSegmentLength()
• getid3_lib::LittleEndian2Int()
• getid3_ogg::warning()
• getid3_ogg::ParseOggPageHeader()
• getid3_flac::__construct()
• getid3_ogg::notice()
• getid3_lib::GetDataImageSize()
• getid3_ogg::__construct()

Used by · 1

• getid3_ogg::Analyze()

Source code

View on Trac ↗View on GitHub ↗

593	public function ParseVorbisComments() {594		$info = &$this->getid3->info;595 596		$OriginalOffset = $this->ftell();597		$commentdata = null;598		$commentdataoffset = 0;599		$VorbisCommentPage = 1;600		$CommentStartOffset = 0;601 602		switch ($info['audio']['dataformat']) {603			case 'vorbis':604			case 'speex':605			case 'opus':606				$CommentStartOffset = $info['ogg']['pageheader'][$VorbisCommentPage]['page_start_offset'];  // Second Ogg page, after header block607				$this->fseek($CommentStartOffset);608				$commentdataoffset = 27 + $info['ogg']['pageheader'][$VorbisCommentPage]['page_segments'];609				$commentdata = $this->fread(self::OggPageSegmentLength($info['ogg']['pageheader'][$VorbisCommentPage], 1) + $commentdataoffset);610 611				if ($info['audio']['dataformat'] == 'vorbis') {612					$commentdataoffset += (strlen('vorbis') + 1);613				}614				else if ($info['audio']['dataformat'] == 'opus') {615					$commentdataoffset += strlen('OpusTags');616				}617 618				break;619 620			case 'flac':621				$CommentStartOffset = $info['flac']['VORBIS_COMMENT']['raw']['offset'] + 4;622				$this->fseek($CommentStartOffset);623				$commentdata = $this->fread($info['flac']['VORBIS_COMMENT']['raw']['block_length']);624				break;625 626			default:627				return false;628		}629 630		$VendorSize = getid3_lib::LittleEndian2Int(substr($commentdata, $commentdataoffset, 4));631		$commentdataoffset += 4;632 633		$info['ogg']['vendor'] = substr($commentdata, $commentdataoffset, $VendorSize);634		$commentdataoffset += $VendorSize;635 636		$CommentsCount = getid3_lib::LittleEndian2Int(substr($commentdata, $commentdataoffset, 4));637		$commentdataoffset += 4;638		$info['avdataoffset'] = $CommentStartOffset + $commentdataoffset;639 640		$basicfields = array('TITLE', 'ARTIST', 'ALBUM', 'TRACKNUMBER', 'GENRE', 'DATE', 'DESCRIPTION', 'COMMENT');641		$ThisFileInfo_ogg_comments_raw = &$info['ogg']['comments_raw'];642		for ($i = 0; $i < $CommentsCount; $i++) {643 644			if ($i >= 10000) {645				// https://github.com/owncloud/music/issues/212#issuecomment-43082336646				$this->warning('Unexpectedly large number ('.$CommentsCount.') of Ogg comments - breaking after reading '.$i.' comments');647				break;648			}649 650			$ThisFileInfo_ogg_comments_raw[$i]['dataoffset'] = $CommentStartOffset + $commentdataoffset;651 652			if ($this->ftell() < ($ThisFileInfo_ogg_comments_raw[$i]['dataoffset'] + 4)) {653				if ($oggpageinfo = $this->ParseOggPageHeader()) {654					$info['ogg']['pageheader'][$oggpageinfo['page_seqno']] = $oggpageinfo;655 656					$VorbisCommentPage++;657 658					// First, save what we haven't read yet659					$AsYetUnusedData = substr($commentdata, $commentdataoffset);660 661					// Then take that data off the end662					$commentdata     = substr($commentdata, 0, $commentdataoffset);663 664					// Add [headerlength] bytes of dummy data for the Ogg Page Header, just to keep absolute offsets correct665					$commentdata .= str_repeat("\x00", 27 + $info['ogg']['pageheader'][$oggpageinfo['page_seqno']]['page_segments']);666					$commentdataoffset += (27 + $info['ogg']['pageheader'][$oggpageinfo['page_seqno']]['page_segments']);667 668					// Finally, stick the unused data back on the end669					$commentdata .= $AsYetUnusedData;670 671					//$commentdata .= $this->fread($info['ogg']['pageheader'][$oggpageinfo['page_seqno']]['page_length']);672					$commentdata .= $this->fread($this->OggPageSegmentLength($info['ogg']['pageheader'][$VorbisCommentPage], 1));

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.ogg.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.

Corrections

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