_wp_utf8_codepoint_span( string $text, int $byte_offset, int $max_code_points, ?int $found_code_points = 0 ): int

381function _wp_utf8_codepoint_span( string $text, int $byte_offset, int $max_code_points, ?int &$found_code_points = 0 ): int {382	$was_at            = $byte_offset;383	$invalid_length    = 0;384	$end               = strlen( $text );385	$found_code_points = 0;386 387	while ( $byte_offset < $end && $found_code_points < $max_code_points ) {388		$needed      = $max_code_points - $found_code_points;389		$chunk_count = _wp_scan_utf8( $text, $byte_offset, $invalid_length, null, $needed );390 391		$found_code_points += $chunk_count;392 393		// Invalid spans only convey one code point count regardless of how long they are.394		if ( 0 !== $invalid_length && $found_code_points < $max_code_points ) {395			++$found_code_points;396			$byte_offset += $invalid_length;397		}398	}399 400	return $byte_offset - $was_at;401}