JezK

Edit File: utf8.php

<?php if ( extension_loaded( 'mbstring' ) ) : /** * Determines if a given byte string represents a valid UTF-8 encoding. * * Note that it’s unlikely for non-UTF-8 data to validate as UTF-8, but * it is still possible. Many texts are simultaneously valid UTF-8, * valid US-ASCII, and valid ISO-8859-1 (`latin1`). * * Example: * * true === wp_is_valid_utf8( '' ); * true === wp_is_valid_utf8( 'just a test' ); * true === wp_is_valid_utf8( "\xE2\x9C\x8F" ); // Pencil, U+270F. * true === wp_is_valid_utf8( "\u{270F}" ); // Pencil, U+270F. * true === wp_is_valid_utf8( '✏' ); // Pencil, U+270F. * * false === wp_is_valid_utf8( "just \xC0 test" ); // Invalid bytes. * false === wp_is_valid_utf8( "\xE2\x9C" ); // Invalid/incomplete sequences. * false === wp_is_valid_utf8( "\xC1\xBF" ); // Overlong sequences. * false === wp_is_valid_utf8( "\xED\xB0\x80" ); // Surrogate halves. * false === wp_is_valid_utf8( "B\xFCch" ); // ISO-8859-1 high-bytes. * // E.g. The “ü” in ISO-8859-1 is a single byte 0xFC, * // but in UTF-8 is the two-byte sequence 0xC3 0xBC. * * A “valid” string consists of “well-formed UTF-8 code unit sequence[s],” meaning * that the bytes conform to the UTF-8 encoding scheme, all characters use the minimal * byte sequence required by UTF-8, and that no sequence encodes a UTF-16 surrogate * code point or any character above the representable range. * * @see https://www.unicode.org/versions/Unicode16.0.0/core-spec/chapter-3/#G32860 * * @since 6.9.0 * * @param string $bytes String which might contain text encoded as UTF-8. * @return bool Whether the provided bytes can decode as valid UTF-8. */ function wp_is_valid_utf8( string $bytes ): bool { return mb_check_encoding( $bytes, 'UTF-8' ); } else : /** * Fallback function for validating UTF-8. * * @ignore * @private * * @since 6.9.0 */ function wp_is_valid_utf8( string $string ): bool { return _wp_is_valid_utf8_fallback( $string ); } endif; if ( extension_loaded( 'mbstring' ) && // Maximal subpart substitution introduced by php/php-src@04e59c916f12b322ac55f22314e31bd0176d01cb. version_compare( PHP_VERSION, '8.1.6', '>=' ) ) : /** * Replaces ill-formed UTF-8 byte sequences with the Unicode Replacement Character. * * Knowing what to do in the presence of text encoding issues can be complicated. * This function replaces invalid spans of bytes to neutralize any corruption that * may be there and prevent it from causing further problems downstream. * * However, it’s not always ideal to replace those bytes. In some settings it may * be best to leave the invalid bytes in the string so that downstream code can handle * them in a specific way. Replacing the bytes too early, like escaping for HTML too * early, can introduce other forms of corruption and data loss. * * When in doubt, use this function to replace spans of invalid bytes. * * Replacement follows the “maximal subpart” algorithm for secure and interoperable * strings. This can lead to sequences of multiple replacement characters in a row. * * Example: * * // Valid strings come through unchanged. * 'test' === wp_scrub_utf8( 'test' ); * * // Invalid sequences of bytes are replaced. * $invalid = "the byte \xC0 is never allowed in a UTF-8 string."; * "the byte \u{FFFD} is never allowed in a UTF-8 string." === wp_scrub_utf8( $invalid, true ); * 'the byte � is never allowed in a UTF-8 string.' === wp_scrub_utf8( $invalid, true ); * * // Maximal subparts are replaced individually. * '.�.' === wp_scrub_utf8( ".\xC0." ); // C0 is never valid. * '.�.' === wp_scrub_utf8( ".\xE2\x8C." ); // Missing A3 at end. * '.��.' === wp_scrub_utf8( ".\xE2\x8C\xE2\x8C." ); // Maximal subparts replaced separately. * '.��.' === wp_scrub_utf8( ".\xC1\xBF." ); // Overlong sequence. * '.���.' === wp_scrub_utf8( ".\xED\xA0\x80." ); // Surrogate half. * * Note! The Unicode Replacement Character is itself a Unicode character (U+FFFD). * Once a span of invalid bytes has been replaced by one, it will not be possible * to know whether the replacement character was originally intended to be there * or if it is the result of scrubbing bytes. It is ideal to leave replacement for * display only, but some contexts (e.g. generating XML or passing data into a * large language model) require valid input strings. * * @since 6.9.0 * * @see https://www.unicode.org/versions/Unicode16.0.0/core-spec/chapter-5/#G40630 * * @param string $text String which is assumed to be UTF-8 but may contain invalid sequences of bytes. * @return string Input text with invalid sequences of bytes replaced with the Unicode replacement character. */ function wp_scrub_utf8( $text ) { /* * While it looks like setting the substitute character could fail, * the internal PHP code will never fail when provided a valid * code point as a number. In this case, there’s no need to check * its return value to see if it succeeded. */ $prev_replacement_character = mb_substitute_character(); mb_substitute_character( 0xFFFD ); $scrubbed = mb_scrub( $text, 'UTF-8' ); mb_substitute_character( $prev_replacement_character ); return $scrubbed; } else : /** * Fallback function for scrubbing UTF-8. * * @ignore * @private * * @since 6.9.0 */ function wp_scrub_utf8( $text ) { return _wp_scrub_utf8_fallback( $text ); } endif; /** * Returns whether the given string contains Unicode noncharacters. * * XML recommends against using noncharacters and HTML forbids their * use in attribute names. Unicode recommends that they not be used * in open exchange of data. * * Noncharacters are code points within the following ranges: * - U+FDD0–U+FDEF * - U+FFFE–U+FFFF * - U+1FFFE, U+1FFFF, U+2FFFE, U+2FFFF, …, U+10FFFE, U+10FFFF * * @see https://www.unicode.org/versions/Unicode17.0.0/core-spec/chapter-23/#G12612 * @see https://www.w3.org/TR/xml/#charsets * @see https://html.spec.whatwg.org/#attributes-2 * * @since 6.9.0 * * @param string $text Are there noncharacters in this string? * @return bool Whether noncharacters were found in the string. */ function wp_has_noncharacters( string $text ): bool { /* * Match the UTF-8 byte sequences directly so malformed UTF-8 elsewhere * in the subject does not cause PCRE's Unicode mode to reject the string. */ return 1 === preg_match( '~ # U+FDD0-U+FDEF, U+FFFE-U+FFFF \xEF(?:\xB7[\x90-\xAF]|\xBF[\xBE\xBF]) | # U+nFFFE/U+nFFFF (?:\xF0[\x9F\xAF\xBF]|[\xF1-\xF3][\x8F\x9F\xAF\xBF]|\xF4\x8F)\xBF[\xBE\xBF] ~x', $text ); }
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