<?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\Yaml;

use Symfony\Component\Yaml\Exception\ParseException;

/**
 * Unescaper encapsulates unescaping rules for single and double-quoted
 * YAML strings.
 *
 * @author Matthew Lewinski <matthew@lewinski.org>
 *
 * @internal
 */
class Unescaper
{
    /**
     * Regex fragment that matches an escaped character in a double quoted string.
     */
    public const REGEX_ESCAPED_CHARACTER = '\\\\(x[0-9a-fA-F]{2}|u[0-9a-fA-F]{4}|U[0-9a-fA-F]{8}|.)';

    /**
     * Unescapes a single quoted string.
     *
     * @param string $value A single quoted string
     */
    public function unescapeSingleQuotedString(string $value): string
    {
        return str_replace('\'\'', '\'', $value);
    }

    /**
     * Unescapes a double quoted string.
     *
     * @param string $value A double quoted string
     */
    public function unescapeDoubleQuotedString(string $value): string
    {
        $callback = function ($match) {
            return $this->unescapeCharacter($match[0]);
        };

        // evaluate the string
        return preg_replace_callback('/'.self::REGEX_ESCAPED_CHARACTER.'/u', $callback, $value);
    }

    /**
     * Unescapes a character that was found in a double-quoted string.
     *
     * @param string $value An escaped character
     */
    private function unescapeCharacter(string $value): string
    {
        switch ($value[1]) {
            case '0':
                return "\x0";
            case 'a':
                return "\x7";
            case 'b':
                return "\x8";
            case 't':
                return "\t";
            case "\t":
                return "\t";
            case 'n':
                return "\n";
            case 'v':
                return "\xB";
            case 'f':
                return "\xC";
            case 'r':
                return "\r";
            case 'e':
                return "\x1B";
            case ' ':
                return ' ';
            case '"':
                return '"';
            case '/':
                return '/';
            case '\\':
                return '\\';
            case 'N':
                // U+0085 NEXT LINE
                return "\xC2\x85";
            case '_':
                // U+00A0 NO-BREAK SPACE
                return "\xC2\xA0";
            case 'L':
                // U+2028 LINE SEPARATOR
                return "\xE2\x80\xA8";
            case 'P':
                // U+2029 PARAGRAPH SEPARATOR
                return "\xE2\x80\xA9";
            case 'x':
                return self::utf8chr(hexdec(substr($value, 2, 2)));
            case 'u':
                return self::utf8chr(hexdec(substr($value, 2, 4)));
            case 'U':
                return self::utf8chr(hexdec(substr($value, 2, 8)));
            default:
                throw new ParseException(sprintf('Found unknown escape character "%s".', $value));
        }
    }

    /**
     * Get the UTF-8 character for the given code point.
     */
    private static function utf8chr(int $c): string
    {
        if (0x80 > $c %= 0x200000) {
            return \chr($c);
        }
        if (0x800 > $c) {
            return \chr(0xC0 | $c >> 6).\chr(0x80 | $c & 0x3F);
        }
        if (0x10000 > $c) {
            return \chr(0xE0 | $c >> 12).\chr(0x80 | $c >> 6 & 0x3F).\chr(0x80 | $c & 0x3F);
        }

        return \chr(0xF0 | $c >> 18).\chr(0x80 | $c >> 12 & 0x3F).\chr(0x80 | $c >> 6 & 0x3F).\chr(0x80 | $c & 0x3F);
    }
}

• [D] Command
• [D] Exception
• [D] Resources
• [D] Tag
• [F] CHANGELOG.md
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• [F] composer.json
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• [F] Dumper.php
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• [F] Escaper.php
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• [F] Inline.php
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• [F] LICENSE
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• [F] Parser.php
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• [F] README.md
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• [F] Unescaper.php
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• [F] Yaml.php
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About Section

About NFC Pay: Our Story and Mission

NFC Pay was founded with a vision to transform the way people handle transactions. Our journey is defined by a commitment to innovation, security, and convenience. We strive to deliver seamless, user-friendly payment solutions that make everyday transactions effortless and secure. Our mission is to empower you to pay with ease and confidence, anytime, anywhere.

• Simplifying Payments, One Tap at a Time.
• Reinventing Your Wallet for Modern Convenience.
• Smart Payments for a Effortless Lifestyle.
• Experience the Ease of Tap and Pay.
• Innovative Solutions for Your Daily Transactions.

FAQ Section

Frequently Asked Questions About NFC Pay

Here are answers to some common questions about NFC Pay. We aim to provide clear and concise information to help you understand how our platform works and how it can benefit you. If you have any further inquiries, please don’t hesitate to contact our support team.

How do I register for NFC Pay?

Download the app and sign up using your email or phone number, then complete the verification process.

Is my payment information secure?

Yes, we use advanced encryption and security protocols to protect your payment details.

Can I add multiple cards to my NFC Pay wallet?

Absolutely, you can link multiple debit or credit cards to your wallet.

How do I transfer money to another user?

Go to the transfer section, select the recipient, enter the amount, and authorize the transfer.

What should I do if I forget my PIN?

Use the “Forgot PIN” feature in the app to reset it following the provided instructions.

How can I activate my merchant account?

Sign up for a merchant account through the app and follow the setup instructions to start accepting payments.

Can I track my payment status?

Yes, you can view and track your payment status in the account dashboard