NumberToLocalizedStringTransformer.php

<?php

/*
 * This file is part of the Symfony package.
 *
 * (c) Fabien Potencier <fabien@symfony.com>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace Symfony\Component\Form\Extension\Core\DataTransformer;

use Symfony\Component\Form\DataTransformerInterface;
use Symfony\Component\Form\Exception\TransformationFailedException;

/**
 * Transforms between a number type and a localized number with grouping
 * (each thousand) and comma separators.
 *
 * @author Bernhard Schussek <bschussek@gmail.com>
 * @author Florian Eckerstorfer <florian@eckerstorfer.org>
 */
class NumberToLocalizedStringTransformer implements DataTransformerInterface
{
    /**
     * Rounds a number towards positive infinity.
     *
     * Rounds 1.4 to 2 and -1.4 to -1.
     */
    const ROUND_CEILING = \NumberFormatter::ROUND_CEILING;

    /**
     * Rounds a number towards negative infinity.
     *
     * Rounds 1.4 to 1 and -1.4 to -2.
     */
    const ROUND_FLOOR = \NumberFormatter::ROUND_FLOOR;

    /**
     * Rounds a number away from zero.
     *
     * Rounds 1.4 to 2 and -1.4 to -2.
     */
    const ROUND_UP = \NumberFormatter::ROUND_UP;

    /**
     * Rounds a number towards zero.
     *
     * Rounds 1.4 to 1 and -1.4 to -1.
     */
    const ROUND_DOWN = \NumberFormatter::ROUND_DOWN;

    /**
     * Rounds to the nearest number and halves to the next even number.
     *
     * Rounds 2.5, 1.6 and 1.5 to 2 and 1.4 to 1.
     */
    const ROUND_HALF_EVEN = \NumberFormatter::ROUND_HALFEVEN;

    /**
     * Rounds to the nearest number and halves away from zero.
     *
     * Rounds 2.5 to 3, 1.6 and 1.5 to 2 and 1.4 to 1.
     */
    const ROUND_HALF_UP = \NumberFormatter::ROUND_HALFUP;

    /**
     * Rounds to the nearest number and halves towards zero.
     *
     * Rounds 2.5 and 1.6 to 2, 1.5 and 1.4 to 1.
     */
    const ROUND_HALF_DOWN = \NumberFormatter::ROUND_HALFDOWN;

    protected $grouping;

    protected $roundingMode;

    private $scale;

    /**
     * @param int|null  $scale
     * @param bool|null $grouping
     * @param int|null  $roundingMode
     */
    public function __construct($scale = null, $grouping = false, $roundingMode = self::ROUND_HALF_UP)
    {
        if (null === $grouping) {
            $grouping = false;
        }

        if (null === $roundingMode) {
            $roundingMode = self::ROUND_HALF_UP;
        }

        $this->scale = $scale;
        $this->grouping = $grouping;
        $this->roundingMode = $roundingMode;
    }

    /**
     * Transforms a number type into localized number.
     *
     * @param int|float $value Number value
     *
     * @return string Localized value
     *
     * @throws TransformationFailedException if the given value is not numeric
     *                                       or if the value can not be transformed
     */
    public function transform($value)
    {
        if (null === $value) {
            return '';
        }

        if (!is_numeric($value)) {
            throw new TransformationFailedException('Expected a numeric.');
        }

        $formatter = $this->getNumberFormatter();
        $value = $formatter->format($value);

        if (intl_is_failure($formatter->getErrorCode())) {
            throw new TransformationFailedException($formatter->getErrorMessage());
        }

        // Convert non-breaking and narrow non-breaking spaces to normal ones
        $value = str_replace(["\xc2\xa0", "\xe2\x80\xaf"], ' ', $value);

        return $value;
    }

    /**
     * Transforms a localized number into an integer or float.
     *
     * @param string $value The localized value
     *
     * @return int|float The numeric value
     *
     * @throws TransformationFailedException if the given value is not a string
     *                                       or if the value can not be transformed
     */
    public function reverseTransform($value)
    {
        if (!\is_string($value)) {
            throw new TransformationFailedException('Expected a string.');
        }

        if ('' === $value) {
            return;
        }

        if (\in_array($value, ['NaN', 'NAN', 'nan'], true)) {
            throw new TransformationFailedException('"NaN" is not a valid number');
        }

        $position = 0;
        $formatter = $this->getNumberFormatter();
        $groupSep = $formatter->getSymbol(\NumberFormatter::GROUPING_SEPARATOR_SYMBOL);
        $decSep = $formatter->getSymbol(\NumberFormatter::DECIMAL_SEPARATOR_SYMBOL);

        if ('.' !== $decSep && (!$this->grouping || '.' !== $groupSep)) {
            $value = str_replace('.', $decSep, $value);
        }

        if (',' !== $decSep && (!$this->grouping || ',' !== $groupSep)) {
            $value = str_replace(',', $decSep, $value);
        }

        if (false !== strpos($value, $decSep)) {
            $type = \NumberFormatter::TYPE_DOUBLE;
        } else {
            $type = PHP_INT_SIZE === 8
                ? \NumberFormatter::TYPE_INT64
                : \NumberFormatter::TYPE_INT32;
        }

        $result = $formatter->parse($value, $type, $position);

        if (intl_is_failure($formatter->getErrorCode())) {
            throw new TransformationFailedException($formatter->getErrorMessage());
        }

        if ($result >= PHP_INT_MAX || $result <= -PHP_INT_MAX) {
            throw new TransformationFailedException('I don\'t have a clear idea what infinity looks like');
        }

        $result = $this->castParsedValue($result);

        if (false !== $encoding = mb_detect_encoding($value, null, true)) {
            $length = mb_strlen($value, $encoding);
            $remainder = mb_substr($value, $position, $length, $encoding);
        } else {
            $length = \strlen($value);
            $remainder = substr($value, $position, $length);
        }

        // After parsing, position holds the index of the character where the
        // parsing stopped
        if ($position < $length) {
            // Check if there are unrecognized characters at the end of the
            // number (excluding whitespace characters)
            $remainder = trim($remainder, " \t\n\r\0\x0b\xc2\xa0");

            if ('' !== $remainder) {
                throw new TransformationFailedException(sprintf('The number contains unrecognized characters: "%s"', $remainder));
            }
        }

        // NumberFormatter::parse() does not round
        return $this->round($result);
    }

    /**
     * Returns a preconfigured \NumberFormatter instance.
     *
     * @return \NumberFormatter
     */
    protected function getNumberFormatter()
    {
        $formatter = new \NumberFormatter(\Locale::getDefault(), \NumberFormatter::DECIMAL);

        if (null !== $this->scale) {
            $formatter->setAttribute(\NumberFormatter::FRACTION_DIGITS, $this->scale);
            $formatter->setAttribute(\NumberFormatter::ROUNDING_MODE, $this->roundingMode);
        }

        $formatter->setAttribute(\NumberFormatter::GROUPING_USED, $this->grouping);

        return $formatter;
    }

    /**
     * @internal
     */
    protected function castParsedValue($value)
    {
        if (\is_int($value) && $value === (int) $float = (float) $value) {
            return $float;
        }

        return $value;
    }

    /**
     * Rounds a number according to the configured scale and rounding mode.
     *
     * @param int|float $number A number
     *
     * @return int|float The rounded number
     */
    private function round($number)
    {
        if (null !== $this->scale && null !== $this->roundingMode) {
            // shift number to maintain the correct scale during rounding
            $roundingCoef = pow(10, $this->scale);
            // string representation to avoid rounding errors, similar to bcmul()
            $number = (string) ($number * $roundingCoef);

            switch ($this->roundingMode) {
                case self::ROUND_CEILING:
                    $number = ceil($number);
                    break;
                case self::ROUND_FLOOR:
                    $number = floor($number);
                    break;
                case self::ROUND_UP:
                    $number = $number > 0 ? ceil($number) : floor($number);
                    break;
                case self::ROUND_DOWN:
                    $number = $number > 0 ? floor($number) : ceil($number);
                    break;
                case self::ROUND_HALF_EVEN:
                    $number = round($number, 0, PHP_ROUND_HALF_EVEN);
                    break;
                case self::ROUND_HALF_UP:
                    $number = round($number, 0, PHP_ROUND_HALF_UP);
                    break;
                case self::ROUND_HALF_DOWN:
                    $number = round($number, 0, PHP_ROUND_HALF_DOWN);
                    break;
            }

            $number /= $roundingCoef;
        }

        return $number;
    }
}