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Text_MappedDiff::__construct( array $from_lines, array $to_lines, array $mapped_from_lines, array $mapped_to_lines )

Source
wp-includes/Text/Diff.php:289
Computes a diff between sequences of strings.

Description

This can be used to compute things like case-insensitive diffs, or diffs which ignore changes in white-space.

Compatibility

WordPress
core
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

$from_linesarray
An array of strings.
$to_linesarray
An array of strings.
$mapped_from_linesarray
This array should have the same size number of elements as $from_lines. The elements in $mapped_from_lines and $mapped_to_lines are what is actually compared when computing the diff.
$mapped_to_linesarray
This array should have the same number of elements as $to_lines.

Performance profile

How much work a call to Text_MappedDiff::__construct() 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 what you pass in.

Instructions
19–33

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 64.

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 · 3 distinct outcomes

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

WhenInstructionsCalls it makes
!$i19::Text_Diff()
!$i26assert(), ::Text_Diff()
!$i33assert(), assert(), ::Text_Diff()

Across PHP versions

Compiles the same on PHP 7.4, 8.1, 8.2, 8.3, 8.4, 8.5 and 8.6-dev: 64 instructions, 19–33 executed per call, 5 branches. The work does not change between versions.

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

Used by · 1

Source code

    function __construct($from_lines, $to_lines,                             $mapped_from_lines, $mapped_to_lines)    {        assert(count($from_lines) == count($mapped_from_lines));        assert(count($to_lines) == count($mapped_to_lines));         parent::Text_Diff($mapped_from_lines, $mapped_to_lines);         $xi = $yi = 0;        for ($i = 0; $i < count($this->_edits); $i++) {            $orig = &$this->_edits[$i]->orig;            if (is_array($orig)) {                $orig = array_slice($from_lines, $xi, count($orig));                $xi += count($orig);            }             $final = &$this->_edits[$i]->final;            if (is_array($final)) {                $final = array_slice($to_lines, $yi, count($final));                $yi += count($final);            }        }    }

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