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

Description

$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

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

13–57

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 69.

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.

Uses · 1

• WP_HTML_Decoder::read_character_reference()Attempt to read a character reference at the given location in a given string, depending on the context in which it's found.

Source code

View on Trac ↗View on GitHub ↗

37	public static function attribute_starts_with( $haystack, $search_text, $case_sensitivity = 'case-sensitive' ): bool {38		$search_length = strlen( $search_text );39		$loose_case    = 'ascii-case-insensitive' === $case_sensitivity;40		$haystack_end  = strlen( $haystack );41		$search_at     = 0;42		$haystack_at   = 0;43 44		while ( $search_at < $search_length && $haystack_at < $haystack_end ) {45			$chars_match = $loose_case46				? strtolower( $haystack[ $haystack_at ] ) === strtolower( $search_text[ $search_at ] )47				: $haystack[ $haystack_at ] === $search_text[ $search_at ];48 49			$is_introducer = '&' === $haystack[ $haystack_at ];50			$next_chunk    = $is_introducer51				? self::read_character_reference( 'attribute', $haystack, $haystack_at, $token_length )52				: null;53 54			// If there's no character reference and the characters don't match, the match fails.55			if ( null === $next_chunk && ! $chars_match ) {56				return false;57			}58 59			// If there's no character reference but the characters do match, then it could still match.60			if ( null === $next_chunk && $chars_match ) {61				++$haystack_at;62				++$search_at;63				continue;64			}65 66			/**67			 * The decoded character reference in `$next_chunk` must be compared with the68			 * corresponding `$search_text` bytes checking for matching prefixes. The remaining69			 * search text may be shorter than the decoded chunk, in which case a partial match70			 * satisfies the prefix. Otherwise, if the decoded chunk is fully matched, the71			 * comparison must continue after advancing the appropriate byte lengths: the character72			 * reference token length in the haystack and the decoded chunk length in the73			 * search text.74			 *75			 * For example, consider searches that have reached the character reference76			 * `&fjlig;` (7 bytes), decoded into the 2-byte chunk `fj`:77			 *78			 *                       $haystack_at79			 *                       │80			 *                       │      ┌─after matching `fj` continue here81			 *                       │      │ (advance by $token_length, 7 bytes)82			 *                       ↓      ↓83			 *     Haystack:    start&fjlig;ord84			 *                       ╰──┬──╯85			 *                          fj - the decoded chunk, tested against the search text.86			 *87			 *                       $search_at88			 *                       │89			 *                       │ ┌─after matching `fj` continue here90			 *                       │ │ (advance by $match_length, 2 bytes)91			 *                       ↓ ↓92			 *     Search A:    startfjord      Compare 2 bytes: `fj` matches,93			 *                                  continue matching at `o`.94			 *95			 *                       $search_at96			 *                       ↓97			 *     Search B:    startf          Compare 1 byte: `f` matches and the98			 *                                  search text is exhausted — prefix confirmed.99			 *100			 *                       $search_at101			 *                       ↓102			 *     Search C:    startfr         Compare 2 bytes: `fj` differs103			 *                                  from `fr`, no match is possible.104			 *105			 * The `min()` is required in both directions: Search A fails if the106			 * comparison length comes from the search text, Search B if it comes107			 * from the chunk.108			 *109			 * After a match each cursor must advance by the appropriate length, the haystack110			 * cursor by the character reference token length, and the search cursor by the111			 * matched length.112			 */113			$match_length = min( strlen( $next_chunk ), $search_length - $search_at );114			if ( 0 !== substr_compare( $search_text, $next_chunk, $search_at, $match_length, $loose_case ) ) {115				return false;116			}

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 7.1.0 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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