<?php
/**
* @see https://github.com/zendframework/zend-diactoros for the canonical source repository
* @copyright Copyright (c) 2015-2017 Zend Technologies USA Inc. (http://www.zend.com)
* @license https://github.com/zendframework/zend-diactoros/blob/master/LICENSE.md New BSD License
*/
namespace Zend\Diactoros;
use Psr\Http\Message\StreamInterface;
use RuntimeException;
use const SEEK_SET;
/**
* Class RelativeStream
*
* Wrapper for default Stream class, representing subpart (starting from given offset) of initial stream.
* It can be used to avoid copying full stream, conserving memory.
* @example see Zend\Diactoros\AbstractSerializer::splitStream()
*/
final class RelativeStream implements StreamInterface
{
/**
* @var StreamInterface
*/
private $decoratedStream;
/**
* @var int
*/
private $offset;
/**
* Class constructor
*
* @param StreamInterface $decoratedStream
* @param int $offset
*/
public function __construct(StreamInterface $decoratedStream, $offset)
{
$this->decoratedStream = $decoratedStream;
$this->offset = (int)$offset;
}
/**
* {@inheritdoc}
*/
public function __toString()
{
if ($this->isSeekable()) {
$this->seek(0);
}
return $this->getContents();
}
/**
* {@inheritdoc}
*/
public function close()
{
$this->decoratedStream->close();
}
/**
* {@inheritdoc}
*/
public function detach()
{
return $this->decoratedStream->detach();
}
/**
* {@inheritdoc}
*/
public function getSize()
{
return $this->decoratedStream->getSize() - $this->offset;
}
/**
* {@inheritdoc}
*/
public function tell()
{
return $this->decoratedStream->tell() - $this->offset;
}
/**
* {@inheritdoc}
*/
public function eof()
{
return $this->decoratedStream->eof();
}
/**
* {@inheritdoc}
*/
public function isSeekable()
{
return $this->decoratedStream->isSeekable();
}
/**
* {@inheritdoc}
*/
public function seek($offset, $whence = SEEK_SET)
{
if ($whence == SEEK_SET) {
return $this->decoratedStream->seek($offset + $this->offset, $whence);
}
return $this->decoratedStream->seek($offset, $whence);
}
/**
* {@inheritdoc}
*/
public function rewind()
{
return $this->seek(0);
}
/**
* {@inheritdoc}
*/
public function isWritable()
{
return $this->decoratedStream->isWritable();
}
/**
* {@inheritdoc}
*/
public function write($string)
{
if ($this->tell() < 0) {
throw new RuntimeException('Invalid pointer position');
}
return $this->decoratedStream->write($string);
}
/**
* {@inheritdoc}
*/
public function isReadable()
{
return $this->decoratedStream->isReadable();
}
/**
* {@inheritdoc}
*/
public function read($length)
{
if ($this->tell() < 0) {
throw new RuntimeException('Invalid pointer position');
}
return $this->decoratedStream->read($length);
}
/**
* {@inheritdoc}
*/
public function getContents()
{
if ($this->tell() < 0) {
throw new RuntimeException('Invalid pointer position');
}
return $this->decoratedStream->getContents();
}
/**
* {@inheritdoc}
*/
public function getMetadata($key = null)
{
return $this->decoratedStream->getMetadata($key);
}
}