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.
Description
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 ) ).
Parameters
$textstringrequired- Count bytes of span in this text.
$byte_offsetintrequired- Start counting at this byte offset.
$max_code_pointsintrequired- Stop counting after this many code points have been seen, or at the end of the string.
$found_code_points?intoptional- Will be set to number of found code points in span, as this might be smaller than the maximum count if the string is not long enough.
Source
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;
}
Changelog
| Version | Description |
|---|---|
| 6.9.0 | Introduced. |
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