Sanitize decomposed filenames in WordPress

sanitize-filename.php

class Sanitize_Filename {

        public function __construct() {
                add_filter( 'wp_handle_upload_prefilter', [ $this, 'sanitize_decomposed_utf8_file' ] );
        }

        /**
         * Sanitize the filename in a file object
         *
         * @param  array $file In file
         * @return array       Out file
         */
        public function sanitize_decomposed_utf8_file( $file ) {
                $file['name'] = $this->sanitize_decomposed_utf8_string( $file['name'] );
                return $file;
        }

        /**
         * Sanitize an decomposed UTF8 string (NFD)
         *
         * @param  string $str Input string
         * @return string      Converted string
         */
        public function sanitize_decomposed_utf8_string( $str ) {
                $chars = [
                        chr( 0xCC ) . chr( 0x88 ) => '', // ¨
                        chr( 0xCC ) . chr( 0x8a ) => '', // °
                        chr( 0xCC ) . chr( 0x81 ) => '', // ´
                ];
                $new_str = strtr( $str, $chars );
                return $new_str;
        }
}