<?php
/*
	Copyright (c) 2003, 2005, 2006, 2009 Danilo Segan <danilo@kvota.net>.
	Copyright (c) 2016 Michal Čihař <michal@cihar.com>

	This file is part of MoTranslator.

	This program is free software; you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation; either version 2 of the License, or
	(at your option) any later version.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU General Public License for more details.

	You should have received a copy of the GNU General Public License along
	with this program; if not, write to the Free Software Foundation, Inc.,
	51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/

namespace PhpMyAdmin\MoTranslator;

/**
 * Simple wrapper around string buffer for
 * random access and values parsing.
 */
class StringReader
{
	private $_str;
	private $_len;

	/**
	 * Constructor.
	 *
	 * @param string $filename Name of file to load
	 */
	public function __construct($filename)
	{
		$this->_str = file_get_contents($filename);
		$this->_len = strlen($this->_str);
	}

	/**
	 * Read number of bytes from given offset.
	 *
	 * @param int $pos   Offset
	 * @param int $bytes Number of bytes to read
	 *
	 * @return string
	 */
	public function read($pos, $bytes)
	{
		if ($pos + $bytes > $this->_len) {
			throw new ReaderException('Not enough bytes!');
		}

		return substr($this->_str, $pos, $bytes);
	}

	/**
	 * Reads a 32bit integer from the stream.
	 *
	 * @param string $unpack Unpack string
	 * @param int    $pos    Position
	 *
	 * @return int Ingerer from the stream
	 */
	public function readint($unpack, $pos)
	{
		$data = unpack($unpack, $this->read($pos, 4));
		$result = $data[1];

		/* We're reading unsigned int, but PHP will happily
		 * give us negative number on 32-bit platforms.
		 *
		 * See also documentation:
		 * https://secure.php.net/manual/en/function.unpack.php#refsect1-function.unpack-notes
		 */
		return $result < 0 ? PHP_INT_MAX : $result;
	}

	/**
	 * Reads an array of integers from the stream.
	 *
	 * @param string $unpack Unpack string
	 * @param int    $pos    Position
	 * @param int    $count  How many elements should be read
	 *
	 * @return array Array of Integers
	 */
	public function readintarray($unpack, $pos, $count)
	{
		return unpack($unpack . $count, $this->read($pos, 4 * $count));
	}
}


/**
 * Exception thrown when file can not be read.
 */
class ReaderException extends \Exception
{
}
