wikimedia/mediawiki-extensions-Wikibase

<?php

declare( strict_types = 1 );

namespace Wikibase\Lib;

use UtfNormal\Validator;

/**
 * StringNormalizer provides several methods for normalizing strings.
 *
 * @license GPL-2.0-or-later
 * @author Daniel Kinzler
 * @author John Erling Blad < jeblad@gmail.com >
 */
class StringNormalizer {

    /**
     * Remove bytes that represent an incomplete Unicode character
     * at the end of string (e.g. bytes of the char are missing)
     *
     * @todo this was stolen from the Language class. Make that code reusable.
     */
    protected function removeBadCharLast( string $string ): string {
        if ( $string != '' ) {
            $char = ord( $string[strlen( $string ) - 1] );
            $m = [];
            if ( $char >= 0xc0 ) {
                # We got the first byte only of a multibyte char; remove it.
                $string = substr( $string, 0, -1 );
            } elseif ( $char >= 0x80 &&
                preg_match( '/^(.*)(?:[\xe0-\xef][\x80-\xbf]|' .
                    '[\xf0-\xf7][\x80-\xbf]{1,2})$/', $string, $m )
            ) {
                # We chopped in the middle of a character; remove it
                $string = $m[1];
            }
        }
        return $string;
    }

    /**
     * Remove bytes that represent an incomplete Unicode character
     * at the start of string (e.g. bytes of the char are missing)
     *
     * @todo this was stolen from the Language class. Make that code reusable.
     */
    protected function removeBadCharFirst( string $string ): string {
        if ( $string != '' ) {
            $char = ord( $string[0] );
            if ( $char >= 0x80 && $char < 0xc0 ) {
                # We chopped in the middle of a character; remove the whole thing
                $string = preg_replace( '/^[\x80-\xbf]+/', '', $string );
            }
        }
        return $string;
    }

    /**
     * Remove incomplete UTF-8 sequences from the beginning and end of the string.
     */
    public function trimBadChars( string $string ): string {
        $string = $this->removeBadCharFirst( $string );
        $string = $this->removeBadCharLast( $string );
        return $string;
    }

    /**
     * Trim initial and trailing whitespace and control chars, and compress some internal control chars.
     */
    public function trimWhitespace( string $inputString ): string {
        $inputString = $this->trimBadChars( $inputString );

        // WARNING: *any* invalid UTF8 sequence causes preg_replace to return an empty string.
        // \p{Cc} only includes general control characters.
        $trimmed = preg_replace( '/\p{Cc}+/u', ' ', $inputString );
        // \p{Z} includes all whitespace characters and invisible separators.
        $trimmed = preg_replace( '/^\p{Z}+|\p{Z}+$/u', '', $trimmed );
        return $trimmed;
    }

    /**
     * Normalize string into NFC by using the cleanup method from UtfNormal.
     */
    public function cleanupToNFC( string $inputString ): string {
        $cleaned = $inputString;
        $cleaned = $this->trimBadChars( $cleaned );
        $cleaned = Validator::cleanUp( $cleaned );
        return $cleaned;
    }

    /**
     * Do a cleanupToNFC after the string is trimmed
     */
    public function trimToNFC( string $inputString ): string {
        return $this->cleanupToNFC( $this->trimWhitespace( $inputString ) );
    }

}