/wp-content/__gravityforms__/currency.php

<?php
if(!class_exists("RGCurrency")){

class RGCurrency{
    private $currency;

    public function __construct($currency){
        if(is_array($currency))
            $this->currency = $currency;
        else
            $this->currency = self::get_currency($currency);
    }

    public function to_number($text){
        $text = strval($text);

        if(is_numeric($text))
            return floatval($text);

        //Removing symbol in unicode format (i.e. &#4444;)
        $text = preg_replace("/&.*?;/", "", $text);

        //Removing all non-numeric characters
        $array = str_split($text);
        $is_negative = false;
        $clean_number = "";
        foreach($array as $char){

            if (($char >= '0' && $char <= '9') || $char=="," || $char==".")
                $clean_number .= $char;
            else if($char == '-')
                $is_negative = true;
        }

        $decimal_separator = $this->currency && $this->currency["decimal_separator"] ? $this->currency["decimal_separator"] : ".";

        //Removing thousand separators but keeping decimal point
        $array = str_split($clean_number);
        $float_number = "";
        for($i=0, $count = sizeof($array); $i<$count; $i++)
        {
            $char = $array[$i];

            if ($char >= '0' && $char <= '9')
                $float_number .= $char;
            else if($char == $decimal_separator)
                $float_number .= ".";
        }

        if($is_negative)
            $float_number = "-" . $float_number;

        return is_numeric($float_number) ? floatval($float_number) : false;
    }

    public function to_money($number, $do_encode=false){

        if(!is_numeric($number))
            $number = $this->to_number($number);

        if($number === false)
            return "";

        $negative = "";
        if(strpos(strval($number), "-") !== false){
            $negative = "-";
            $number = floatval(substr($number,1));
        }

        $money = number_format($number, $this->currency["decimals"], $this->currency["decimal_separator"], $this->currency["thousand_separator"]);
        $symbol_left = !empty($this->currency["symbol_left"]) ? $this->currency["symbol_left"] . $this->currency["symbol_padding"] : "";
        $symbol_right = !empty($this->currency["symbol_right"]) ? $this->currency["symbol_padding"] . $this->currency["symbol_right"] : "";

        if($do_encode){
           $symbol_left = html_entity_decode($symbol_left);
           $symbol_right = html_entity_decode($symbol_right);
        }

        return $negative . $symbol_left . $money . $symbol_right;
    }

    public static function get_currency($code){
        $currencies = self::get_currencies();
        return $currencies[$code];
    }

    public static function get_currencies(){
        $currencies = array(
        "AUD" => array("name" => __("Australian Dollar", "gravityforms"), "symbol_left" => '$', "symbol_right" => "", "symbol_padding" => " ", "thousand_separator" => ',', "decimal_separator" => '.', "decimals" => 2),
        "BRL" => array("name" => __("Brazilian Real", "gravityforms"), "symbol_left" => 'R$', "symbol_right" => "", "symbol_padding" => " ", "thousand_separator" => '.', "decimal_separator" => ',', "decimals" => 2),
        "CAD" => array("name" => __("Canadian Dollar", "gravityforms"), "symbol_left" => '$', "symbol_right" => "CAD", "symbol_padding" => " ", "thousand_separator" => ',', "decimal_separator" => '.', "decimals" => 2),
        "CZK" => array("name" => __("Czech Koruna", "gravityforms"), "symbol_left" => '', "symbol_right" => "&#75;&#269;", "symbol_padding" => " ", "thousand_separator" => ' ', "decimal_separator" => ',', "decimals" => 2),
        "DKK" => array("name" => __("Danish Krone", "gravityforms"), "symbol_left" => 'Kr', "symbol_right" => "", "symbol_padding" => " ", "thousand_separator" => '.', "decimal_separator" => ',', "decimals" => 2),
        "EUR" => array("name" => __("Euro", "gravityforms"), "symbol_left" => '', "symbol_right" => "&#8364;", "symbol_padding" => " ", "thousand_separator" => '.', "decimal_separator" => ',', "decimals" => 2),
        "HKD" => array("name" => __("Hong Kong Dollar", "gravityforms"), "symbol_left" => 'HK$', "symbol_right" => "", "symbol_padding" => "", "thousand_separator" => ',', "decimal_separator" => '.', "decimals" => 2),
        "HUF" => array("name" => __("Hungarian Forint", "gravityforms"), "symbol_left" => '', "symbol_right" => "Ft", "symbol_padding" => " ", "thousand_separator" => '.', "decimal_separator" => ',', "decimals" => 2),
        "ILS" => array("name" => __("Israeli New Sheqel", "gravityforms"), "symbol_left" => '&#8362;', "symbol_right" => "", "symbol_padding" => " ", "thousand_separator" => ',', "decimal_separator" => '.', "decimals" => 2),
        "JPY" => array("name" => __("Japanese Yen", "gravityforms"), "symbol_left" => '&#165;', "symbol_right" => "", "symbol_padding" => " ", "thousand_separator" => ',', "decimal_separator" => '', "decimals" => 0),
        "MYR" => array("name" => __("Malaysian Ringgit", "gravityforms"), "symbol_left" => '&#82;&#77;', "symbol_right" => "", "symbol_padding" => " ", "thousand_separator" => ',', "decimal_separator" => '.', "decimals" => 2),
        "MXN" => array("name" => __("Mexican Peso", "gravityforms"), "symbol_left" => '$', "symbol_right" => "", "symbol_padding" => " ", "thousand_separator" => ',', "decimal_separator" => '.', "decimals" => 2),
        "NOK" => array("name" => __("Norwegian Krone", "gravityforms"), "symbol_left" => 'Kr', "symbol_right" => "", "symbol_padding" => " ", "thousand_separator" => '.', "decimal_separator" => ',', "decimals" => 2),
        "NZD" => array("name" => __("New Zealand Dollar", "gravityforms"), "symbol_left" => '$', "symbol_right" => "", "symbol_padding" => " ", "thousand_separator" => ',', "decimal_separator" => '.', "decimals" => 2),
        "PHP" => array("name" => __("Philippine Peso", "gravityforms"), "symbol_left" => 'Php', "symbol_right" => "", "symbol_padding" => " ", "thousand_separator" => ',', "decimal_separator" => '.', "decimals" => 2),
        "PLN" => array("name" => __("Polish Zloty", "gravityforms"), "symbol_left" => '&#122;&#322;', "symbol_right" => "", "symbol_padding" => " ", "thousand_separator" => '.', "decimal_separator" => ',', "decimals" => 2),
        "GBP" => array("name" => __("Pound Sterling", "gravityforms"), "symbol_left" => '&#163;', "symbol_right" => "", "symbol_padding" => " ", "thousand_separator" => ',', "decimal_separator" => '.', "decimals" => 2),
        "SGD" => array("name" => __("Singapore Dollar", "gravityforms"), "symbol_left" => '$', "symbol_right" => "", "symbol_padding" => " ", "thousand_separator" => ',', "decimal_separator" => '.', "decimals" => 2),
        "SEK" => array("name" => __("Swedish Krona", "gravityforms"), "symbol_left" => '', "symbol_right" => "Kr", "symbol_padding" => " ", "thousand_separator" => ' ', "decimal_separator" => ',', "decimals" => 2),
        "CHF" => array("name" => __("Swiss Franc", "gravityforms"), "symbol_left" => 'Fr.', "symbol_right" => "", "symbol_padding" => " ", "thousand_separator" => "'", "decimal_separator" => '.', "decimals" => 2),
        "TWD" => array("name" => __("Taiwan New Dollar", "gravityforms"), "symbol_left" => '$', "symbol_right" => "", "symbol_padding" => " ", "thousand_separator" => ',', "decimal_separator" => '.', "decimals" => 2),
        "THB" => array("name" => __("Thai Baht", "gravityforms"), "symbol_left" => '&#3647;', "symbol_right" => "", "symbol_padding" => " ", "thousand_separator" => ',', "decimal_separator" => '.', "decimals" => 2),
        "USD" => array("name" => __("U.S. Dollar", "gravityforms"), "symbol_left" => '$', "symbol_right" => "", "symbol_padding" =>  "", "thousand_separator" => ',', "decimal_separator" => '.', "decimals" => 2)
        );

        return apply_filters("gform_currencies", $currencies);
    }
}

}
?>