WP_Http_Encoding::compatible_gzinflate( string $gz_data ): string|false
- Since
- 2.8.1
- Source
wp-includes/class-wp-http-encoding.php:104
Description
Certain Servers will return deflated data with headers which PHP's gzinflate() function cannot handle out of the box. The following function has been created from various snippets on the gzinflate() PHP documentation.
Warning: Magic numbers within. Due to the potential different formats that the compressed data may be returned in, some "magic offsets" are needed to ensure proper decompression takes place. For a simple pragmatic way to determine the magic offset in use, see: https://core.trac.wordpress.org/ticket/18273
Compatibility
- WordPress
- since 2.8.1
- PHP
- 7.4–8.6-dev
- 6.7.7
- 6.8.8
- 6.9.7
- 7.0.4
- 7.1.0
Present in every tracked release (6.7.7 to 7.1.0), and compiles on PHP 7.4 through 8.6-dev.
Parameters
$gz_datastring- String to decompress.
Return value
string|false- Decompressed string on success, false on failure.
Performance profile
How much work a call to WP_Http_Encoding::compatible_gzinflate() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.
- Cost class
- Trivial
- Scaling
- Constant
- Instructions
- 13–55
- Plugin surface
- None
- Called by
- 1
Touches nothing outside its own arguments.
No loop in the body: the same number of instructions runs whatever you pass in.
Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 57.
Nothing here hands control to plugin code.
1 place in core call this, so the cost is paid more often than your own code shows.
What one call costs · 5 distinct outcomes
One number would be a lie: the work depends on which branch runs. These are every distinct cost WP_Http_Encoding::compatible_gzinflate() can have, taken from its control-flow graph on PHP 8.5.
| When | Instructions | Calls it makes |
|---|---|---|
!$gz_data | 13 | gzinflate() |
$gz_data && !$flg && $decompressed !== false | 22–37 | ord(), gzinflate() |
$gz_data && !$flg && $decompressed === false | 31–46 | ord(), gzinflate(), gzinflate() |
$gz_data && $flg && $decompressed !== false | 39–46 | ord(), unpack(), gzinflate() |
$gz_data && $flg && $decompressed === false | 48–55 | ord(), unpack(), gzinflate(), gzinflate() |
Across PHP versions
| PHP | Compiled | Executed | Branches | Notes |
|---|---|---|---|---|
| 8.6-dev | 57 | 13–55 | 8 | |
| 8.5 | 57 | 13–55 | 8 | |
| 8.4 | 57 | 13–55 | 8 | 21 fewer instructions than PHP 8.3 |
| 8.3 | 78 | 19–76 | 8 | |
| 8.2 | 78 | 19–76 | 8 | |
| 8.1 | 78 | 19–76 | 8 | |
| 7.4 | 78 | 19–76 | 8 |
An instruction is not a fixed amount of time, so a matching count is not necessarily the same speed; what it rules out is a difference in the work itself.
Uses · 1
- str_starts_with()Polyfill for `str_starts_with()` function added in PHP 8.0.
Used by · 1
- WP_Http_Encoding::decompress()Decompression of deflated string.
Source code
public static function compatible_gzinflate( $gz_data ) { // Compressed data might contain a full header, if so strip it for gzinflate(). if ( str_starts_with( $gz_data, "\x1f\x8b\x08" ) ) { $i = 10; $flg = ord( substr( $gz_data, 3, 1 ) ); if ( $flg > 0 ) { if ( $flg & 4 ) { list($xlen) = unpack( 'v', substr( $gz_data, $i, 2 ) ); $i = $i + 2 + $xlen; } if ( $flg & 8 ) { $i = strpos( $gz_data, "\0", $i ) + 1; } if ( $flg & 16 ) { $i = strpos( $gz_data, "\0", $i ) + 1; } if ( $flg & 2 ) { $i = $i + 2; } } $decompressed = @gzinflate( substr( $gz_data, $i, -8 ) ); if ( false !== $decompressed ) { return $decompressed; } } // Compressed data from java.util.zip.Deflater amongst others. $decompressed = @gzinflate( substr( $gz_data, 2 ) ); if ( false !== $decompressed ) { return $decompressed; } return false; }Changelog
Introduced in 2.8.1. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
About this page
- Parsed data
- Generated from the wordpress-develop 6.7.7 tag, from
src/wp-includes/class-wp-http-encoding.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.