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_wp_utf8_encode_fallback › WordPress Function

Since6.9.0
Deprecatedn/a
› _wp_utf8_encode_fallback ( $iso_8859_1_text )
Access:
  • private
Parameters:
  • (string) $iso_8859_1_text Text treated as ISO-8859-1 (latin1) bytes.
    Required: Yes
See:
  • utf8_encode()
Returns:
  • (string) Text converted into UTF-8.
Defined at:
Codex:

Converts a string from ISO-8859-1 to UTF-8, maintaining backwards compatibility with the deprecated function from the PHP standard library.



Related Functions: _wp_utf8_decode_fallback, _wp_scrub_utf8_fallback, _wp_is_valid_utf8_fallback, _wp_utf8_codepoint_span, _wp_has_noncharacters_fallback

Source 

function _wp_utf8_encode_fallback( $iso_8859_1_text ) {
	$iso_8859_1_text = (string) $iso_8859_1_text;
	$at              = 0;
	$was_at          = 0;
	$end             = strlen( $iso_8859_1_text );
	$utf8            = '';

	while ( $at < $end ) {
		// US-ASCII bytes are identical in ISO-8859-1 and UTF-8. These are 0x00–0x7F.
		$ascii_byte_count = strspn(
			$iso_8859_1_text,
			"\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f" .
			"\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f" .
			" !\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~\x7f",
			$at
		);

		if ( $ascii_byte_count > 0 ) {
			$at += $ascii_byte_count;
			continue;
		}

		// All other bytes transform into two-byte UTF-8 sequences.
		$code_point = ord( $iso_8859_1_text[ $at ] );
		$byte1      = chr( 0xC0 | ( $code_point >> 6 ) );
		$byte2      = chr( 0x80 | ( $code_point & 0x3F ) );

		$utf8 .= substr( $iso_8859_1_text, $was_at, $at - $was_at );
		$utf8 .= "{$byte1}{$byte2}";

		++$at;
		$was_at = $at;
	}

	if ( 0 === $was_at ) {
		return $iso_8859_1_text;
	}

	$utf8 .= substr( $iso_8859_1_text, $was_at );
	return $utf8;
}