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<?php
/**
* Copyright (c) 2014 Robin Appelman <icewind@owncloud.com>
* This file is licensed under the Licensed under the MIT license:
* http://opensource.org/licenses/MIT
*/
namespace Icewind\Streams;
/**
* Wrapper that provides callbacks for write, read and close
*
* The following options should be passed in the context when opening the stream
* [
* 'callback' => [
* 'source' => resource
* ]
* ]
*
* All callbacks are called after the operation is executed on the source stream
*/
class SeekableWrapper extends Wrapper {
/**
* @var resource
*/
protected $cache;
/**
* Wraps a stream to make it seekable
*
* @param resource $source
* @return resource
*
* @throws \BadMethodCallException
*/
public static function wrap($source) {
$context = stream_context_create(array(
'callback' => array(
'source' => $source
)
));
return Wrapper::wrapSource($source, $context, 'callback', '\Icewind\Streams\SeekableWrapper');
}
public function dir_opendir($path, $options) {
return false;
}
public function stream_open($path, $mode, $options, &$opened_path) {
$this->loadContext('callback');
$this->cache = fopen('php://temp', 'w+');
return true;
}
protected function readTill($position) {
$current = ftell($this->source);
if ($position > $current) {
$data = parent::stream_read($position - $current);
$cachePosition = ftell($this->cache);
fseek($this->cache, $current);
fwrite($this->cache, $data);
fseek($this->cache, $cachePosition);
}
}
public function stream_read($count) {
$current = ftell($this->cache);
$this->readTill($current + $count);
return fread($this->cache, $count);
}
public function stream_seek($offset, $whence = SEEK_SET) {
if ($whence === SEEK_SET) {
$target = $offset;
} else if ($whence === SEEK_CUR) {
$current = ftell($this->cache);
$target = $current + $offset;
} else {
return false;
}
$this->readTill($target);
return fseek($this->cache, $target) === 0;
}
public function stream_tell() {
return ftell($this->cache);
}
public function stream_eof() {
return parent::stream_eof() and (ftell($this->source) === ftell($this->cache));
}
}
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