yf_common_num2string class

    public function cent_number($force = null)
    {
        if ($force === null) {
            $result = $this->_cent_number_force;
        } else {
            $result = (bool) $force;
            $this->_cent_number_force = $result;
        }
        return $result;
    }

    public function cent_zero($force = null)
    {
        if ($force === null) {
            $result = $this->_cent_zero_force;
        } else {
            $result = (bool) $force;
            $this->_cent_zero_force = $result;
        }
        return $result;
    }

    public function currency_id($currency_id = null, $set = true)
    {
        $_lang_id = $this->lang_id();
        $_currency_id = &$this->_currency_id;
        $currency = &$this->words[$_lang_id]['currency'];
        if (empty($currency_id)) {
            $result = $_currency_id;
        } else {
            $result = strtoupper($currency_id);
            $result = isset($currency[$result]) ? $result : $_currency_id;
            $set && $_currency_id = $result;
        }
        return $result;
    }

    public function lang_id($lang_id = null, $set = true)
    {
        $_lang_id = &$this->_lang_id;
        $_lang_id ??= $this->_default_lang_id();
        if (empty($lang_id)) {
            $result = $_lang_id;
        } else {
            $words = &$this->words;
            $result = strtoupper($lang_id);
            $result = isset($words[$result]) ? $result : $_lang_id;
            $set && $_lang_id = $result;
        }
        return $result;
    }

    public function num2str($float, $currency_id = null, $lang_id = null, $set = false)
    {
        $lang_id = $this->lang_id($lang_id, $set);
        $currency_id = $this->currency_id($currency_id, $set);
        $words = &$this->words[$lang_id];
        $digits = &$words['digits'];
        $signs = &$words['signs'];
        $units = &$words['units'];
        // prepare options
        $sign_force = $this->sign();
        $cent_number_force = $this->cent_number();
        $cent_zero_force = $this->cent_zero();
        $units[0] = &$words['currency'][$currency_id][0];
        $units[1] = &$words['currency'][$currency_id][1];
        // separate float on sign, integer, fractional
        $result = [];
        $number = trim((float) $float);
        // trim fractional by 2 digits
        $number_format = localeconv();
        $decimal_point = $number_format['decimal_point'];
        $thousands_sep = [' ', '.', ',', "'", '`'];
        [$part1, $part2] = explode($decimal_point, $number) + [1 => ''];
        $part2 = substr($part2 . '00', 0, 2);
        $number = str_replace($thousands_sep, '', $part1) . '0' . $part2;
        // add sign word
        $sign_minus = substr($number, 0, 1) == '-';
        // minus
        $sign_minus && $result[] = $signs[1];
        // plus
        ! $sign_minus > 0 && $sign_force && $result[] = $signs[0];
        // remove sign
        $sign_minus && $number = substr($number, 1);
        // format number by 3 digits
        while (strlen($number) % 3) {
            $number = '0' . $number;
        }
        // processing number digits
        $digits_array = str_split($number, 3);
        $units_count = count((array) $digits_array) - 1;
        foreach ($digits_array as $unit => $digits3) {
            $unit = $units_count - $unit;
            // skip zero if not dollar or cent
            if ((int) $digits3 == 0 && ($unit > 1 || ! ($cent_zero_force || $unit))) {
                continue;
            }
            if ($unit < 2 && ! (int) $digits3) {
                // zero if dollar or cent
                $result[] = $cent_number_force && ! $unit ? 0 : $words['zero'];
            } else {
                if ($cent_number_force && ! $unit) {
                    // cent as int
                    $result[] = (int) $digits3;
                } else {
                    // separate by 1 digit
                    $d3 = substr($digits3, 0, 1);
                    $d2 = substr($digits3, 1, 1);
                    $d1 = substr($digits3, 2, 1);
                    // 1xx-9xx
                    if ($d3 > 0) {
                        $result[] = $digits[3][$d3];
                    }
                    // 20-99
                    if ($d2 > 1) {
                        $result[] = $digits[2][$d2];
                    }
                    // 10-19
                    if ($d2 == 1) {
                        $result[] = $digits[1][$d1];
                    }
                    // 1-9
                    if ($d1 > 0 && $d2 != 1) {
                        $gender = $units[$unit][3];
                        if ($gender > -1) {
                            $result[] = $digits[0][$gender][$d1];
                        }
                    }
                }
            }
            $result[] = $this->morph($digits3, $units[$unit]);
        }
        $result = implode(' ', $result);
        return $result;
    }

    public function sign($force = null)
    {
        if ($force === null) {
            $result = $this->_sign_force;
        } else {
            $result = (bool) $force;
            $this->_sign_force = $result;
        }
        return $result;
    }

    public function _default_lang_id()
    {
        $id = $this->LANG_MAP[strtolower((string) conf('language'))] ?? 'EN';
        return isset($this->words[$id]) ? $id : (string) current(array_keys($this->words));
    }

    public function _init()
    {
        $_lang_id = &$this->_lang_id;
        $_currency_id = &$this->_currency_id;
        $words = &$this->words;
        // the language is resolved on first use (lang_id()), conf('language') may be set after this object exists
        $_lang_id = null;
        // currency: the first of the default language (UAH in every language)
        $_currency_id = current(array_keys($words[$this->_default_lang_id()]['currency']));
    }