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<?php |
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|
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declare (strict_types=1); |
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namespace WCPOS\Vendor\GuzzleHttp\Psr7; |
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|
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use WCPOS\Vendor\Psr\Http\Message\StreamInterface; |
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/** |
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* Decorator used to return only a subset of a stream. |
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*/ |
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final class LimitStream implements StreamInterface |
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{ |
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use StreamDecoratorTrait; |
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use NonSerializableStreamTrait; |
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/** @var int Offset to start reading from */ |
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private int $offset; |
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/** @var int Limit the number of bytes that can be read */ |
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private int $limit; |
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private StreamInterface $stream; |
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/** |
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* @param StreamInterface $stream Stream to wrap |
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* @param int $limit Total number of bytes to allow to be read |
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* from the stream. Pass -1 for no limit. |
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* @param int $offset Position to seek to before reading (only |
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* works on seekable streams). |
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*/ |
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public function __construct(StreamInterface $stream, int $limit = -1, int $offset = 0) |
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{ |
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$this->stream = $stream; |
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$this->setLimit($limit); |
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$this->setOffset($offset); |
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} |
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public function eof() : bool |
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{ |
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// Always return true if the underlying stream is EOF |
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if ($this->stream->eof()) { |
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return \true; |
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} |
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// No limit and the underlying stream is not at EOF |
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if ($this->limit === -1) { |
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return \false; |
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} |
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return $this->stream->tell() >= Integers::add($this->offset, $this->limit); |
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} |
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/** |
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* Returns the size of the limited subset of data |
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*/ |
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public function getSize() : ?int |
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{ |
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if (null === ($length = $this->stream->getSize())) { |
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return null; |
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} |
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$size = $length - $this->offset; |
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if ($this->limit !== -1) { |
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$size = \min($this->limit, $size); |
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} |
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return \max(0, $size); |
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} |
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/** |
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* Allow for a bounded seek on the read limited stream |
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*/ |
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public function seek(int $offset, int $whence = \SEEK_SET) : void |
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{ |
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if ($whence !== \SEEK_SET || $offset < 0) { |
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throw new \RuntimeException(\sprintf('Cannot seek to offset %s with whence %s', $offset, $whence)); |
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} |
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$offset = Integers::add($this->offset, $offset); |
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if ($this->limit !== -1) { |
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$upperBound = Integers::add($this->offset, $this->limit); |
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if ($offset > $upperBound) { |
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$offset = $upperBound; |
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} |
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} |
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$this->stream->seek($offset); |
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} |
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/** |
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* Give a relative tell() |
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*/ |
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public function tell() : int |
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{ |
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return $this->stream->tell() - $this->offset; |
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} |
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/** |
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* Set the offset to start limiting from |
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* |
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* @param int $offset Offset to seek to and begin byte limiting from |
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* |
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* @throws \RuntimeException if the stream cannot be seeked. |
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*/ |
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public function setOffset(int $offset) : void |
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{ |
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$offset = Integers::assertNonNegativeInteger($offset, 'Offset'); |
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$current = $this->stream->tell(); |
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if ($current === $offset) { |
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$this->offset = $offset; |
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return; |
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} |
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// If the stream cannot seek to the offset position, then read to it. |
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if ($this->stream->isSeekable()) { |
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$this->stream->seek($offset); |
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$this->offset = $offset; |
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return; |
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} |
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if ($current > $offset) { |
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throw new \RuntimeException("Could not seek to stream offset {$offset}"); |
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} |
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while ($current < $offset) { |
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if ($this->stream->eof()) { |
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$this->offset = $current; |
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return; |
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} |
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$result = $this->stream->read($offset - $current); |
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if ($result === '') { |
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if ($this->stream->eof()) { |
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$this->offset = $current; |
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return; |
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} |
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throw new \RuntimeException("Could not seek to stream offset {$offset}"); |
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} |
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$current = Integers::add($current, \strlen($result)); |
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} |
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$this->offset = $offset; |
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} |
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/** |
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* Set the limit of bytes that the decorator allows to be read from the |
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* stream. |
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* |
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* @param int $limit Number of bytes to allow to be read from the stream. |
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* Use -1 for no limit. |
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*/ |
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public function setLimit(int $limit) : void |
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{ |
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$this->limit = Integers::assertLimitInteger($limit, 'Limit'); |
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} |
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public function read(int $length) : string |
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{ |
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if ($length < 0) { |
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throw new \RuntimeException('Length parameter cannot be negative'); |
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} |
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if ($this->limit === -1) { |
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return $this->stream->read($length); |
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} |
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// Check if the current position is less than the total allowed |
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// bytes + original offset |
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$remaining = Integers::add($this->offset, $this->limit) - $this->stream->tell(); |
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if ($remaining > 0) { |
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// Only return the amount of requested data, ensuring that the byte |
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// limit is not exceeded |
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return $this->stream->read(\min($remaining, $length)); |
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} |
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return ''; |
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} |
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} |
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|
