<?php
/**
 * Part of the Joomla Framework Filesystem Package
 *
 * @copyright  Copyright (C) 2005 - 2019 Open Source Matters, Inc. All rights reserved.
 * @license    GNU General Public License version 2 or later; see LICENSE
 */

namespace Joomla\Filesystem;

/**
 * Generic Buffer stream handler
 *
 * This class provides a generic buffer stream.  It can be used to store/retrieve/manipulate
 * string buffers with the standard PHP filesystem I/O methods.
 *
 * @since  1.0
 */
class Buffer
{
	/**
	 * Stream position
	 *
	 * @var    integer
	 * @since  1.0
	 */
	public $position = 0;

	/**
	 * Buffer name
	 *
	 * @var    string
	 * @since  1.0
	 */
	public $name;

	/**
	 * Buffer hash
	 *
	 * @var    array
	 * @since  1.0
	 */
	public $buffers = array();

	/**
	 * Function to open file or url
	 *
	 * @param   string   $path        The URL that was passed
	 * @param   string   $mode        Mode used to open the file @see fopen
	 * @param   integer  $options     Flags used by the API, may be STREAM_USE_PATH and STREAM_REPORT_ERRORS
	 * @param   string   $openedPath  Full path of the resource. Used with STREAN_USE_PATH option
	 *
	 * @return  boolean
	 *
	 * @since   1.0
	 * @see     streamWrapper::stream_open
	 */
	public function stream_open($path, $mode, $options, &$openedPath)
	{
		$url                        = parse_url($path);
		$this->name                 = $url['host'];
		$this->buffers[$this->name] = null;
		$this->position             = 0;

		return true;
	}

	/**
	 * Read stream
	 *
	 * @param   integer  $count  How many bytes of data from the current position should be returned.
	 *
	 * @return  mixed    The data from the stream up to the specified number of bytes (all data if
	 *                   the total number of bytes in the stream is less than $count. Null if
	 *                   the stream is empty.
	 *
	 * @see     streamWrapper::stream_read
	 * @since   1.0
	 */
	public function stream_read($count)
	{
		$ret = substr($this->buffers[$this->name], $this->position, $count);
		$this->position += \strlen($ret);

		return $ret;
	}

	/**
	 * Write stream
	 *
	 * @param   string  $data  The data to write to the stream.
	 *
	 * @return  integer
	 *
	 * @see     streamWrapper::stream_write
	 * @since   1.0
	 */
	public function stream_write($data)
	{
		$left                       = substr($this->buffers[$this->name], 0, $this->position);
		$right                      = substr($this->buffers[$this->name], $this->position + \strlen($data));
		$this->buffers[$this->name] = $left . $data . $right;
		$this->position += \strlen($data);

		return \strlen($data);
	}

	/**
	 * Function to get the current position of the stream
	 *
	 * @return  integer
	 *
	 * @see     streamWrapper::stream_tell
	 * @since   1.0
	 */
	public function stream_tell()
	{
		return $this->position;
	}

	/**
	 * Function to test for end of file pointer
	 *
	 * @return  boolean  True if the pointer is at the end of the stream
	 *
	 * @see     streamWrapper::stream_eof
	 * @since   1.0
	 */
	public function stream_eof()
	{
		return $this->position >= \strlen($this->buffers[$this->name]);
	}

	/**
	 * The read write position updates in response to $offset and $whence
	 *
	 * @param   integer  $offset  The offset in bytes
	 * @param   integer  $whence  Position the offset is added to
	 *                            Options are SEEK_SET, SEEK_CUR, and SEEK_END
	 *
	 * @return  boolean  True if updated
	 *
	 * @see     streamWrapper::stream_seek
	 * @since   1.0
	 */
	public function stream_seek($offset, $whence)
	{
		switch ($whence)
		{
			case SEEK_SET:
				if ($offset < \strlen($this->buffers[$this->name]) && $offset >= 0)
				{
					$this->position = $offset;

					return true;
				}

				return false;

			case SEEK_CUR:
				if ($offset >= 0)
				{
					$this->position += $offset;

					return true;
				}

				return false;

			case SEEK_END:
				if (\strlen($this->buffers[$this->name]) + $offset >= 0)
				{
					$this->position = \strlen($this->buffers[$this->name]) + $offset;

					return true;
				}

				return false;

			default:
				return false;
		}
	}
}

// Register the stream
stream_wrapper_register('buffer', 'Joomla\\Filesystem\\Buffer');