getid3_id3v2::Analyze(): 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_id3v2::Analyze() 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

27–155

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 1038.

Plugin surface

None

Nothing here hands control to plugin code.

Called by

0

Nothing in core calls this; the cost is only what you spend yourself.

What one call costs · 7 distinct outcomes

One number would be a lie: the work depends on which branch runs. These are every distinct cost getid3_id3v2::Analyze() 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 · 17

• getid3_id3v2::fseek()
• getid3_id3v2::fread()
• getid3_id3v2::error()
• getid3_lib::BigEndian2Int()
• getid3_id3v2::DeUnsynchronise()
• getid3_id3v2::LookupExtendedHeaderRestrictionsTagSizeLimits()
• getid3_id3v2::LookupExtendedHeaderRestrictionsTextEncodings()
• getid3_id3v2::LookupExtendedHeaderRestrictionsTextFieldSize()
• getid3_id3v2::LookupExtendedHeaderRestrictionsImageEncoding()
• getid3_id3v2::LookupExtendedHeaderRestrictionsImageSizeSize()
• getid3_id3v2::warning()
• getid3_id3v2::ID3v2HeaderLength()

Source code

View on Trac ↗View on GitHub ↗

29	public function Analyze() {30		$info = &$this->getid3->info;31 32		//    Overall tag structure:33		//        +-----------------------------+34		//        |      Header (10 bytes)      |35		//        +-----------------------------+36		//        |       Extended Header       |37		//        | (variable length, OPTIONAL) |38		//        +-----------------------------+39		//        |   Frames (variable length)  |40		//        +-----------------------------+41		//        |           Padding           |42		//        | (variable length, OPTIONAL) |43		//        +-----------------------------+44		//        | Footer (10 bytes, OPTIONAL) |45		//        +-----------------------------+46 47		//    Header48		//        ID3v2/file identifier      "ID3"49		//        ID3v2 version              $04 0050		//        ID3v2 flags                (%ab000000 in v2.2, %abc00000 in v2.3, %abcd0000 in v2.4.x)51		//        ID3v2 size             4 * %0xxxxxxx52 53 54		// shortcuts55		$info['id3v2']['header'] = true;56		$thisfile_id3v2                  = &$info['id3v2'];57		$thisfile_id3v2['flags']         =  array();58		$thisfile_id3v2_flags            = &$thisfile_id3v2['flags'];59 60 61		$this->fseek($this->StartingOffset);62		$header = $this->fread(10);63		if (substr($header, 0, 3) == 'ID3'  &&  strlen($header) == 10) {64 65			$thisfile_id3v2['majorversion'] = ord($header[3]);66			$thisfile_id3v2['minorversion'] = ord($header[4]);67 68			// shortcut69			$id3v2_majorversion = &$thisfile_id3v2['majorversion'];70 71		} else {72 73			unset($info['id3v2']);74			return false;75 76		}77 78		if ($id3v2_majorversion > 4) { // this script probably won't correctly parse ID3v2.5.x and above (if it ever exists)79 80			$this->error('this script only parses up to ID3v2.4.x - this tag is ID3v2.'.$id3v2_majorversion.'.'.$thisfile_id3v2['minorversion']);81			return false;82 83		}84 85		$id3_flags = ord($header[5]);86		switch ($id3v2_majorversion) {87			case 2:88				// %ab000000 in v2.289				$thisfile_id3v2_flags['unsynch']     = (bool) ($id3_flags & 0x80); // a - Unsynchronisation90				$thisfile_id3v2_flags['compression'] = (bool) ($id3_flags & 0x40); // b - Compression91				break;92 93			case 3:94				// %abc00000 in v2.395				$thisfile_id3v2_flags['unsynch']     = (bool) ($id3_flags & 0x80); // a - Unsynchronisation96				$thisfile_id3v2_flags['exthead']     = (bool) ($id3_flags & 0x40); // b - Extended header97				$thisfile_id3v2_flags['experim']     = (bool) ($id3_flags & 0x20); // c - Experimental indicator98				break;99 100			case 4:101				// %abcd0000 in v2.4102				$thisfile_id3v2_flags['unsynch']     = (bool) ($id3_flags & 0x80); // a - Unsynchronisation103				$thisfile_id3v2_flags['exthead']     = (bool) ($id3_flags & 0x40); // b - Extended header104				$thisfile_id3v2_flags['experim']     = (bool) ($id3_flags & 0x20); // c - Experimental indicator105				$thisfile_id3v2_flags['isfooter']    = (bool) ($id3_flags & 0x10); // d - Footer present106				break;107		}108

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.tag.id3v2.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.

Corrections

Something wrong on this page? Report it and it gets fixed in the next regeneration.