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    <h3>Editing: CachingStream.php</h3>
    <textarea name="content" rows="20" cols="80">&lt;?php

declare(strict_types=1);

namespace GuzzleHttp\Psr7;

use Psr\Http\Message\StreamInterface;

/**
 * Stream decorator that can cache previously read bytes from a sequentially
 * read stream.
 */
final class CachingStream implements StreamInterface
{
    use StreamDecoratorTrait;

    /** @var StreamInterface Stream being wrapped */
    private $remoteStream;

    /** @var int Number of bytes to skip reading due to a write on the buffer */
    private $skipReadBytes = 0;

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

    /**
     * We will treat the buffer object as the body of the stream
     *
     * @param StreamInterface $stream Stream to cache. The cursor is assumed to be at the beginning of the stream.
     * @param StreamInterface $target Optionally specify where data is cached
     */
    public function __construct(
        StreamInterface $stream,
        StreamInterface $target = null
    ) {
        $this-&gt;remoteStream = $stream;
        $this-&gt;stream = $target ?: new Stream(Utils::tryFopen('php://temp', 'r+'));
    }

    public function getSize(): ?int
    {
        $remoteSize = $this-&gt;remoteStream-&gt;getSize();

        if (null === $remoteSize) {
            return null;
        }

        return max($this-&gt;stream-&gt;getSize(), $remoteSize);
    }

    public function rewind(): void
    {
        $this-&gt;seek(0);
    }

    public function seek($offset, $whence = SEEK_SET): void
    {
        if ($whence === SEEK_SET) {
            $byte = $offset;
        } elseif ($whence === SEEK_CUR) {
            $byte = $offset + $this-&gt;tell();
        } elseif ($whence === SEEK_END) {
            $size = $this-&gt;remoteStream-&gt;getSize();
            if ($size === null) {
                $size = $this-&gt;cacheEntireStream();
            }
            $byte = $size + $offset;
        } else {
            throw new \InvalidArgumentException('Invalid whence');
        }

        $diff = $byte - $this-&gt;stream-&gt;getSize();

        if ($diff &gt; 0) {
            // Read the remoteStream until we have read in at least the amount
            // of bytes requested, or we reach the end of the file.
            while ($diff &gt; 0 &amp;&amp; !$this-&gt;remoteStream-&gt;eof()) {
                $this-&gt;read($diff);
                $diff = $byte - $this-&gt;stream-&gt;getSize();
            }
        } else {
            // We can just do a normal seek since we've already seen this byte.
            $this-&gt;stream-&gt;seek($byte);
        }
    }

    public function read($length): string
    {
        // Perform a regular read on any previously read data from the buffer
        $data = $this-&gt;stream-&gt;read($length);
        $remaining = $length - strlen($data);

        // More data was requested so read from the remote stream
        if ($remaining) {
            // If data was written to the buffer in a position that would have
            // been filled from the remote stream, then we must skip bytes on
            // the remote stream to emulate overwriting bytes from that
            // position. This mimics the behavior of other PHP stream wrappers.
            $remoteData = $this-&gt;remoteStream-&gt;read(
                $remaining + $this-&gt;skipReadBytes
            );

            if ($this-&gt;skipReadBytes) {
                $len = strlen($remoteData);
                $remoteData = substr($remoteData, $this-&gt;skipReadBytes);
                $this-&gt;skipReadBytes = max(0, $this-&gt;skipReadBytes - $len);
            }

            $data .= $remoteData;
            $this-&gt;stream-&gt;write($remoteData);
        }

        return $data;
    }

    public function write($string): int
    {
        // When appending to the end of the currently read stream, you'll want
        // to skip bytes from being read from the remote stream to emulate
        // other stream wrappers. Basically replacing bytes of data of a fixed
        // length.
        $overflow = (strlen($string) + $this-&gt;tell()) - $this-&gt;remoteStream-&gt;tell();
        if ($overflow &gt; 0) {
            $this-&gt;skipReadBytes += $overflow;
        }

        return $this-&gt;stream-&gt;write($string);
    }

    public function eof(): bool
    {
        return $this-&gt;stream-&gt;eof() &amp;&amp; $this-&gt;remoteStream-&gt;eof();
    }

    /**
     * Close both the remote stream and buffer stream
     */
    public function close(): void
    {
        $this-&gt;remoteStream-&gt;close();
        $this-&gt;stream-&gt;close();
    }

    private function cacheEntireStream(): int
    {
        $target = new FnStream(['write' =&gt; 'strlen']);
        Utils::copyToStream($this, $target);

        return $this-&gt;tell();
    }
}
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