<?php

declare(strict_types=1);

namespace ZipStream;

use OverflowException;

class Bigint
{
    /**
     * @var int[]
     */
    private $bytes = [0, 0, 0, 0, 0, 0, 0, 0];

    /**
     * Initialize the bytes array
     *
     * @param int $value
     */
    public function __construct(int $value = 0)
    {
        $this->fillBytes($value, 0, 8);
    }

    /**
     * Get an instance
     *
     * @param int $value
     * @return Bigint
     */
    public static function init(int $value = 0): self
    {
        return new self($value);
    }

    /**
     * Fill bytes from low to high
     *
     * @param int $low
     * @param int $high
     * @return Bigint
     */
    public static function fromLowHigh(int $low, int $high): self
    {
        $bigint = new self();
        $bigint->fillBytes($low, 0, 4);
        $bigint->fillBytes($high, 4, 4);
        return $bigint;
    }

    /**
     * Get high 32
     *
     * @return int
     */
    public function getHigh32(): int
    {
        return $this->getValue(4, 4);
    }

    /**
     * Get value from bytes array
     *
     * @param int $end
     * @param int $length
     * @return int
     */
    public function getValue(int $end = 0, int $length = 8): int
    {
        $result = 0;
        for ($i = $end + $length - 1; $i >= $end; $i--) {
            $result <<= 8;
            $result |= $this->bytes[$i];
        }
        return $result;
    }

    /**
     * Get low FF
     *
     * @param bool $force
     * @return float
     */
    public function getLowFF(bool $force = false): float
    {
        if ($force || $this->isOver32()) {
            return (float)0xFFFFFFFF;
        }
        return (float)$this->getLow32();
    }

    /**
     * Check if is over 32
     *
     * @psalm-suppress ArgumentTypeCoercion
     * @param bool $force
     * @return bool
     */
    public function isOver32(bool $force = false): bool
    {
        // value 0xFFFFFFFF already needs a Zip64 header
        return $force ||
            max(array_slice($this->bytes, 4, 4)) > 0 ||
            min(array_slice($this->bytes, 0, 4)) === 0xFF;
    }

    /**
     * Get low 32
     *
     * @return int
     */
    public function getLow32(): int
    {
        return $this->getValue(0, 4);
    }

    /**
     * Get hexadecimal
     *
     * @return string
     */
    public function getHex64(): string
    {
        $result = '0x';
        for ($i = 7; $i >= 0; $i--) {
            $result .= sprintf('%02X', $this->bytes[$i]);
        }
        return $result;
    }

    /**
     * Add
     *
     * @param Bigint $other
     * @return Bigint
     */
    public function add(self $other): self
    {
        $result = clone $this;
        $overflow = false;
        for ($i = 0; $i < 8; $i++) {
            $result->bytes[$i] += $other->bytes[$i];
            if ($overflow) {
                $result->bytes[$i]++;
                $overflow = false;
            }
            if ($result->bytes[$i] & 0x100) {
                $overflow = true;
                $result->bytes[$i] &= 0xFF;
            }
        }
        if ($overflow) {
            throw new OverflowException();
        }
        return $result;
    }

    /**
     * Fill the bytes field with int
     *
     * @param int $value
     * @param int $start
     * @param int $count
     * @return void
     */
    protected function fillBytes(int $value, int $start, int $count): void
    {
        for ($i = 0; $i < $count; $i++) {
            $this->bytes[$start + $i] = $i >= PHP_INT_SIZE ? 0 : $value & 0xFF;
            $value >>= 8;
        }
    }
}

• [D] Exception
• [D] Option
• [F] Bigint.php
  Delete
• [F] DeflateStream.php
  Delete
• [F] Exception.php
  Delete
• [F] File.php
  Delete
• [F] Stream.php
  Delete
• [F] ZipStream.php
  Delete

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