_wp_utf8_codepoint_span() │ WP 6.9.0

Given a starting offset within a string and a maximum number of code points, return how many bytes are occupied by the span of characters.

Invalid spans of bytes count as a single code point according to the maximal subpart rule. This function is a fallback method for calling strlen( mb_substr( substr($text,$at), 0,$max_code_points) ).

No Hooks.

Returns

Int. Number of bytes spanned by the code points.

Usage

_wp_utf8_codepoint_span( $text, $byte_offset, $max_code_points, ?int $found_code_points ): int;

$text(string) (required)

Count bytes of span in this text.

$byte_offset(int) (required)

Start counting at this byte offset.

$max_code_points(int) (required)

Stop counting after this many code points have been seen, or at the end of the string.

?int $found_code_points(passed by reference — &)

.

Changelog

_wp_utf8_codepoint_span() wp utf8 codepoint span code ^{WP 7.0}

function _wp_utf8_codepoint_span( string $text, int $byte_offset, int $max_code_points, ?int &$found_code_points = 0 ): int {
	$was_at            = $byte_offset;
	$invalid_length    = 0;
	$end               = strlen( $text );
	$found_code_points = 0;

	while ( $byte_offset < $end && $found_code_points < $max_code_points ) {
		$needed      = $max_code_points - $found_code_points;
		$chunk_count = _wp_scan_utf8( $text, $byte_offset, $invalid_length, null, $needed );

		$found_code_points += $chunk_count;

		// Invalid spans only convey one code point count regardless of how long they are.
		if ( 0 !== $invalid_length && $found_code_points < $max_code_points ) {
			++$found_code_points;
			$byte_offset += $invalid_length;
		}
	}

	return $byte_offset - $was_at;
}