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WordPress

WP_HTML_Decoder::attribute_starts_with( string $haystack, string $search_text, string $case_sensitivity = 'case-sensitive' ): bool

Since
6.6.0
Source
wp-includes/html-api/class-wp-html-decoder.php:34
Indicates if an attribute value starts with a given raw string value.

Description

Use this method to determine if an attribute value starts with a given string, regardless of how it might be encoded in HTML. For instance, http: could be represented as http: or as http: or as http: or as http:, or in many other ways.

Example:

$value = 'http://wordpress.org/';
true === WP_HTML_Decoder::attribute_starts_with( $value, 'http:', 'ascii-case-insensitive' );
false === WP_HTML_Decoder::attribute_starts_with( $value, 'https:', 'ascii-case-insensitive' );

Compatibility

WordPress
since 6.6.0
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

$haystackstring
String containing the raw non-decoded attribute value.
$search_textstring
Does the attribute value start with this plain string.
$case_sensitivitystringoptional
Pass 'ascii-case-insensitive' to ignore ASCII case when matching.
Default 'case-sensitive'.Default: 'case-sensitive'

Return value

bool
Whether the attribute value starts with the given string.

Performance profile

How much work a call to WP_HTML_Decoder::attribute_starts_with() 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
12–54

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 66.

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 · 8 distinct outcomes

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

WhenInstructionsCalls it makes
always12–27none
$search_at && $haystack_at && $case_sensitivity !== "ascii-case-insensitive" && $next_chunk === null34::read_character_reference()
$search_at && $haystack_at && $case_sensitivity === "ascii-case-insensitive" && $next_chunk === null34strtolower(), strtolower()
$search_at && $haystack_at && $case_sensitivity !== "ascii-case-insensitive"38–40substr_compare()
$search_at && $haystack_at && $case_sensitivity === "ascii-case-insensitive" && $next_chunk === null41strtolower(), strtolower(), ::read_character_reference()
$search_at && $haystack_at && $case_sensitivity !== "ascii-case-insensitive"45–47::read_character_reference(), substr_compare()
$search_at && $haystack_at && $case_sensitivity === "ascii-case-insensitive"45–47strtolower(), strtolower(), substr_compare()
$search_at && $haystack_at && $case_sensitivity === "ascii-case-insensitive"52–54strtolower(), strtolower(), ::read_character_reference(), substr_compare()

Across PHP versions

PHPCompiledExecutedBranchesNotes
8.6-dev6512–5391 fewer instruction than PHP 8.5
8.56612–549
8.46612–549
8.36612–549
8.26612–549
8.16612–5492 fewer instructions than PHP 7.4
7.46812–559

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

Source code

View on Trac View on GitHub 

	public static function attribute_starts_with( $haystack, $search_text, $case_sensitivity = 'case-sensitive' ): bool {		$search_length = strlen( $search_text );		$loose_case    = 'ascii-case-insensitive' === $case_sensitivity;		$haystack_end  = strlen( $haystack );		$search_at     = 0;		$haystack_at   = 0; 		while ( $search_at < $search_length && $haystack_at < $haystack_end ) {			$chars_match = $loose_case				? strtolower( $haystack[ $haystack_at ] ) === strtolower( $search_text[ $search_at ] )				: $haystack[ $haystack_at ] === $search_text[ $search_at ]; 			$is_introducer = '&' === $haystack[ $haystack_at ];			$next_chunk    = $is_introducer				? self::read_character_reference( 'attribute', $haystack, $haystack_at, $token_length )				: null; 			// If there's no character reference and the characters don't match, the match fails.			if ( null === $next_chunk && ! $chars_match ) {				return false;			} 			// If there's no character reference but the character do match, then it could still match.			if ( null === $next_chunk && $chars_match ) {				++$haystack_at;				++$search_at;				continue;			} 			// If there is a character reference, then the decoded value must exactly match what follows in the search string.			if ( 0 !== substr_compare( $search_text, $next_chunk, $search_at, strlen( $next_chunk ), $loose_case ) ) {				return false;			} 			// The character reference matched, so continue checking.			$haystack_at += $token_length;			$search_at   += strlen( $next_chunk );		} 		return true;	}

Changelog

Introduced in 6.6.0. 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 6.9.7 tag, from src/wp-includes/html-api/class-wp-html-decoder.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.
Corrections
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