getid3_handler::fread( int $bytes ): string|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

$bytesint

Return value

string|false

Performance profile

How much work a call to getid3_handler::fread() 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

Heavy

Reads or writes the filesystem via fread().

Scaling

Scales with input

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

Instructions

6–39

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 85.

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 it touches

• filesystemfilesystem accessfread()called directly

What one call costs · 4 distinct outcomes

One number would be a lie: the work depends on which branch runs. These are every distinct cost getid3_handler::fread() can have, taken from its control-flow graph on PHP 8.5.

Uses · 3

• getid3_exception::__construct()
• getid3_handler::ftell()
• getid3_lib::intValueSupported()

Used by · 1

• getid3_handler::saveAttachment()

Source code

View on Trac ↗View on GitHub ↗

2236	protected function fread($bytes) {2237		if ($this->data_string_flag) {2238			$this->data_string_position += $bytes;2239			return substr($this->data_string, $this->data_string_position - $bytes, $bytes);2240		}2241		if ($bytes == 0) {2242			return '';2243		} elseif ($bytes < 0) {2244			throw new getid3_exception('cannot fread('.$bytes.' from '.$this->ftell().')', 10);2245		}2246		$pos = $this->ftell() + $bytes;2247		if (!getid3_lib::intValueSupported($pos)) {2248			throw new getid3_exception('cannot fread('.$bytes.' from '.$this->ftell().') because beyond PHP filesystem limit', 10);2249		}2250 2251		//return fread($this->getid3->fp, $bytes);2252		/*2253		* https://www.getid3.org/phpBB3/viewtopic.php?t=19302254		* "I found out that the root cause for the problem was how getID3 uses the PHP system function fread().2255		* It seems to assume that fread() would always return as many bytes as were requested.2256		* However, according the PHP manual (http://php.net/manual/en/function.fread.php), this is the case only with regular local files, but not e.g. with Linux pipes.2257		* The call may return only part of the requested data and a new call is needed to get more."2258		*/2259		$contents = '';2260		do {2261			//if (($this->getid3->memory_limit > 0) && ($bytes > $this->getid3->memory_limit)) {2262			if (($this->getid3->memory_limit > 0) && (($bytes / $this->getid3->memory_limit) > 0.99)) { // enable a more-fuzzy match to prevent close misses generating errors like "PHP Fatal error: Allowed memory size of 33554432 bytes exhausted (tried to allocate 33554464 bytes)"2263				throw new getid3_exception('cannot fread('.$bytes.' from '.$this->ftell().') that is more than available PHP memory ('.$this->getid3->memory_limit.')', 10);2264			}2265			$part = fread($this->getid3->fp, $bytes);2266			$partLength  = strlen($part);2267			$bytes      -= $partLength;2268			$contents   .= $part;2269		} while (($bytes > 0) && ($partLength > 0));2270		return $contents;2271	}

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/getid3.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.

Corrections

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