getid3_id3v1::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_id3v1::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

36–237

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 284.

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 · 38 distinct outcomes

One number would be a lie: the work depends on which branch runs. These are every distinct cost getid3_id3v1::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 · 8

• getid3_lib::intValueSupported()
• getid3_id3v1::warning()
• getid3_id3v1::fseek()
• getid3_id3v1::fread()
• getid3_id3v1::cutfield()
• getid3_id3v1::LookupGenreName()
• getid3_id3v1::GenerateID3v1Tag()
• getid3_id3v1::LookupGenreID()

Source code

View on Trac ↗View on GitHub ↗

26	public function Analyze() {27		$info = &$this->getid3->info;28 29		if (!getid3_lib::intValueSupported($info['filesize'])) {30			$this->warning('Unable to check for ID3v1 because file is larger than '.round(PHP_INT_MAX / 1073741824).'GB');31			return false;32		} elseif ($info['filesize'] < 128) {33			$this->warning('Unable to check for ID3v1 because file is too small');34			return false;35		}36 37		if($info['filesize'] < 256) {38			$this->fseek(-128, SEEK_END);39			$preid3v1 = '';40			$id3v1tag = $this->fread(128);41		} else {42			$this->fseek(-256, SEEK_END);43			$preid3v1 = $this->fread(128);44			$id3v1tag = $this->fread(128);45		}46 47 48		if (substr($id3v1tag, 0, 3) == 'TAG') {49 50			$info['avdataend'] = $info['filesize'] - 128;51 52			$ParsedID3v1            = array();53			$ParsedID3v1['title']   = $this->cutfield(substr($id3v1tag,   3, 30));54			$ParsedID3v1['artist']  = $this->cutfield(substr($id3v1tag,  33, 30));55			$ParsedID3v1['album']   = $this->cutfield(substr($id3v1tag,  63, 30));56			$ParsedID3v1['year']    = $this->cutfield(substr($id3v1tag,  93,  4));57			$ParsedID3v1['comment'] =                 substr($id3v1tag,  97, 30);  // can't remove nulls yet, track detection depends on them58			$ParsedID3v1['genreid'] =             ord(substr($id3v1tag, 127,  1));59 60			// If second-last byte of comment field is null and last byte of comment field is non-null61			// then this is ID3v1.1 and the comment field is 28 bytes long and the 30th byte is the track number62			if (($id3v1tag[125] === "\x00") && ($id3v1tag[126] !== "\x00")) {63				$ParsedID3v1['track_number'] = ord(substr($ParsedID3v1['comment'], 29,  1));64				$ParsedID3v1['comment']      =     substr($ParsedID3v1['comment'],  0, 28);65			}66			$ParsedID3v1['comment'] = $this->cutfield($ParsedID3v1['comment']);67 68			$ParsedID3v1['genre'] = $this->LookupGenreName($ParsedID3v1['genreid']);69			if (!empty($ParsedID3v1['genre'])) {70				unset($ParsedID3v1['genreid']);71			}72			if (empty($ParsedID3v1['genre']) || ($ParsedID3v1['genre'] == 'Unknown')) {73				unset($ParsedID3v1['genre']);74			}75 76			foreach ($ParsedID3v1 as $key => $value) {77				$ParsedID3v1['comments'][$key][0] = $value;78			}79			$ID3v1encoding = $this->getid3->encoding_id3v1;80			if ($this->getid3->encoding_id3v1_autodetect) {81				// ID3v1 encoding detection hack START82				// ID3v1 is defined as always using ISO-8859-1 encoding, but it is not uncommon to find files tagged with ID3v1 using Windows-1251 or other character sets83				// Since ID3v1 has no concept of character sets there is no certain way to know we have the correct non-ISO-8859-1 character set, but we can guess84				foreach ($ParsedID3v1['comments'] as $tag_key => $valuearray) {85					foreach ($valuearray as $key => $value) {86						if (preg_match('#^[\\x00-\\x40\\x80-\\xFF]+$#', $value) && !ctype_digit((string) $value)) { // check for strings with only characters above chr(128) and punctuation/numbers, but not just numeric strings (e.g. track numbers or years)87							foreach (array('Windows-1251', 'KOI8-R') as $id3v1_bad_encoding) {88								if (function_exists('mb_convert_encoding') && @mb_convert_encoding($value, $id3v1_bad_encoding, $id3v1_bad_encoding) === $value) {89									$ID3v1encoding = $id3v1_bad_encoding;90									$this->warning('ID3v1 detected as '.$id3v1_bad_encoding.' text encoding in '.$tag_key);91									break 3;92								} elseif (function_exists('iconv') && @iconv($id3v1_bad_encoding, $id3v1_bad_encoding, $value) === $value) {93									$ID3v1encoding = $id3v1_bad_encoding;94									$this->warning('ID3v1 detected as '.$id3v1_bad_encoding.' text encoding in '.$tag_key);95									break 3;96								}97							}98						}99					}100				}101				// ID3v1 encoding detection hack END102			}103 104			// ID3v1 data is supposed to be padded with NULL characters, but some taggers pad with spaces105			$GoodFormatID3v1tag = $this->GenerateID3v1Tag(

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.id3v1.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.

Corrections

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