<?php

declare(strict_types=1);

namespace GuzzleHttp\Psr7;

use Psr\Http\Message\StreamInterface;

/**
 * Decorator used to return only a subset of a stream.
 */
final class LimitStream implements StreamInterface
{
    use StreamDecoratorTrait;

    /** @var int Offset to start reading from */
    private $offset;

    /** @var int Limit the number of bytes that can be read */
    private $limit;

    /** @var StreamInterface */
    private $stream;

    /**
     * @param StreamInterface $stream Stream to wrap
     * @param int             $limit  Total number of bytes to allow to be read
     *                                from the stream. Pass -1 for no limit.
     * @param int             $offset Position to seek to before reading (only
     *                                works on seekable streams).
     */
    public function __construct(
        StreamInterface $stream,
        int $limit = -1,
        int $offset = 0
    ) {
        $this->stream = $stream;
        $this->setLimit($limit);
        $this->setOffset($offset);
    }

    public function eof(): bool
    {
        // Always return true if the underlying stream is EOF
        if ($this->stream->eof()) {
            return true;
        }

        // No limit and the underlying stream is not at EOF
        if ($this->limit === -1) {
            return false;
        }

        return $this->stream->tell() >= $this->offset + $this->limit;
    }

    /**
     * Returns the size of the limited subset of data
     */
    public function getSize(): ?int
    {
        if (null === ($length = $this->stream->getSize())) {
            return null;
        } elseif ($this->limit === -1) {
            return $length - $this->offset;
        } else {
            return min($this->limit, $length - $this->offset);
        }
    }

    /**
     * Allow for a bounded seek on the read limited stream
     */
    public function seek($offset, $whence = SEEK_SET): void
    {
        if ($whence !== SEEK_SET || $offset < 0) {
            throw new \RuntimeException(sprintf(
                'Cannot seek to offset %s with whence %s',
                $offset,
                $whence
            ));
        }

        $offset += $this->offset;

        if ($this->limit !== -1) {
            if ($offset > $this->offset + $this->limit) {
                $offset = $this->offset + $this->limit;
            }
        }

        $this->stream->seek($offset);
    }

    /**
     * Give a relative tell()
     */
    public function tell(): int
    {
        return $this->stream->tell() - $this->offset;
    }

    /**
     * Set the offset to start limiting from
     *
     * @param int $offset Offset to seek to and begin byte limiting from
     *
     * @throws \RuntimeException if the stream cannot be seeked.
     */
    public function setOffset(int $offset): void
    {
        $current = $this->stream->tell();

        if ($current !== $offset) {
            // If the stream cannot seek to the offset position, then read to it
            if ($this->stream->isSeekable()) {
                $this->stream->seek($offset);
            } elseif ($current > $offset) {
                throw new \RuntimeException("Could not seek to stream offset $offset");
            } else {
                $this->stream->read($offset - $current);
            }
        }

        $this->offset = $offset;
    }

    /**
     * Set the limit of bytes that the decorator allows to be read from the
     * stream.
     *
     * @param int $limit Number of bytes to allow to be read from the stream.
     *                   Use -1 for no limit.
     */
    public function setLimit(int $limit): void
    {
        $this->limit = $limit;
    }

    public function read($length): string
    {
        if ($this->limit === -1) {
            return $this->stream->read($length);
        }

        // Check if the current position is less than the total allowed
        // bytes + original offset
        $remaining = ($this->offset + $this->limit) - $this->stream->tell();
        if ($remaining > 0) {
            // Only return the amount of requested data, ensuring that the byte
            // limit is not exceeded
            return $this->stream->read(min($remaining, $length));
        }

        return '';
    }
}

• [D] Exception
• [F] AppendStream.php
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• [F] BufferStream.php
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• [F] CachingStream.php
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• [F] DroppingStream.php
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• [F] FnStream.php
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• [F] Header.php
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• [F] HttpFactory.php
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• [F] InflateStream.php
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• [F] LazyOpenStream.php
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• [F] LimitStream.php
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• [F] Message.php
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• [F] MessageTrait.php
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• [F] MimeType.php
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• [F] MultipartStream.php
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• [F] NoSeekStream.php
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• [F] PumpStream.php
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• [F] Query.php
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• [F] Request.php
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• [F] Response.php
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• [F] Rfc7230.php
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• [F] ServerRequest.php
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• [F] Stream.php
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• [F] StreamDecoratorTrait.php
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• [F] StreamWrapper.php
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• [F] UploadedFile.php
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• [F] Uri.php
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• [F] UriComparator.php
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• [F] UriNormalizer.php
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• [F] UriResolver.php
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• [F] Utils.php
  Delete

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Encryption is a process that transforms data into a secure format, known as ciphertext, which can only be deciphered using a specific decryption key. This means that even if data is intercepted during transmission, it remains unreadable and protected from unauthorized access. Encryption is essential in safeguarding sensitive payment information, such as credit card details and personal data, during online transactions.
Tokenization, on the other hand, involves substituting sensitive data with unique identifiers or "tokens." These tokens serve as placeholders and have no value outside of the specific transaction context. If intercepted, tokens are meaningless and cannot be used to access the original sensitive data. This method significantly reduces the risk of fraud and data breaches, as the actual payment information is not stored or transmitted.
Together, encryption and tokenization form a powerful security framework. Encryption ensures that data is protected during transmission, while tokenization minimizes the risk of exposing sensitive information by replacing it with secure, non-sensitive tokens.
These technologies are integral to modern payment platforms, providing a robust defense against cyber threats. By implementing advanced encryption and tokenization techniques, businesses can enhance the security of digital transactions, ensuring that users' financial and personal information remains safe. This comprehensive approach not only builds user trust but also fortifies the overall security infrastructure of digital payment systems. As cyber threats evolve, the continued advancement of encryption and tokenization will be crucial in maintaining secure and reliable payment processes.

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