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<?php
/**
* Zend Framework
*
* LICENSE
*
* This source file is subject to the new BSD license that is bundled
* with this package in the file LICENSE.txt.
* It is also available through the world-wide-web at this URL:
* http://framework.zend.com/license/new-bsd
* If you did not receive a copy of the license and are unable to
* obtain it through the world-wide-web, please send an email
* to license@zend.com so we can send you a copy immediately.
*
* @category Zend
* @package Zend_Amf
* @subpackage Util
* @copyright Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
* @license http://framework.zend.com/license/new-bsd New BSD License
* @version $Id: BinaryStream.php 18951 2009-11-12 16:26:19Z alexander $
*/
/**
* Utility class to walk through a data stream byte by byte with conventional names
*
* @package Zend_Amf
* @subpackage Util
* @copyright Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
* @license http://framework.zend.com/license/new-bsd New BSD License
*/
class Zend_Amf_Util_BinaryStream
{
/**
* @var string Byte stream
*/
protected $_stream;
/**
* @var int Length of stream
*/
protected $_streamLength;
/**
* @var bool BigEndian encoding?
*/
protected $_bigEndian;
/**
* @var int Current position in stream
*/
protected $_needle;
/**
* Constructor
*
* Create a refrence to a byte stream that is going to be parsed or created
* by the methods in the class. Detect if the class should use big or
* little Endian encoding.
*
* @param string $stream use '' if creating a new stream or pass a string if reading.
* @return void
*/
public function __construct($stream)
{
if (!is_string($stream)) {
require_once 'Zend/Amf/Exception.php';
throw new Zend_Amf_Exception('Inputdata is not of type String');
}
$this->_stream = $stream;
$this->_needle = 0;
$this->_streamLength = strlen($stream);
$testEndian = unpack("C*", pack("S*", 256));
$this->_bigEndian = 1;
}
/**
* Returns the current stream
*
* @return string
*/
public function getStream()
{
return $this->_stream;
}
/**
* Read the number of bytes in a row for the length supplied.
*
* @todo Should check that there are enough bytes left in the stream we are about to read.
* @param int $length
* @return string
* @throws Zend_Amf_Exception for buffer underrun
*/
public function readBytes($length)
{
if (($length + $this->_needle) > strlen($this->_stream)) {
require_once 'Zend/Amf/Exception.php';
throw new Zend_Amf_Exception("Buffer underrun at needle position: " . $this->_needle . " while requesting length: " . $length);
}
$bytes = substr($this->_stream, $this->_needle, $length);
$this->_needle += $length;
return $bytes;
}
/**
* Write any length of bytes to the stream
*
* Usually a string.
*
* @param string $bytes
* @return Zend_Amf_Util_BinaryStream
*/
public function writeBytes($bytes)
{
$this->_stream .= $bytes;
return $this;
}
/**
* Reads a signed byte
*
* @return int Value is in the range of -128 to 127.
*/
public function readByte()
{
$byte = ord($this->_stream[$this->_needle++]);
return $byte;
}
/**
* Writes the passed string into a signed byte on the stream.
*
* @param string $stream
* @return Zend_Amf_Util_BinaryStream
*/
public function writeByte($stream)
{
$this->_stream .= pack("c",$stream);
return $this;
}
/**
* Reads a signed 32-bit integer from the data stream.
*
* @return int Value is in the range of -2147483648 to 2147483647
*/
public function readInt()
{
$int = ($this->readByte() << 8) + $this->readByte();
return $int;
}
/**
* Write an the integer to the output stream as a 32 bit signed integer
*
* @param int $stream
* @return Zend_Amf_Util_BinaryStream
*/
public function writeInt($stream)
{
$this->_stream .= pack("n", $stream);
return $this;
}
/**
* Reads a UTF-8 string from the data stream
*
* @return string A UTF-8 string produced by the byte representation of characters
*/
public function readUtf()
{
$length = $this->readInt();
return $this->readBytes($length);
}
/**
* Wite a UTF-8 string to the outputstream
*
* @param string $stream
* @return Zend_Amf_Util_BinaryStream
*/
public function writeUtf($stream)
{
$this->writeInt(strlen($stream));
$this->_stream .= $stream;
return $this;
}
/**
* Read a long UTF string
*
* @return string
*/
public function readLongUtf()
{
$length = $this->readLong();
return $this->readBytes($length);
}
/**
* Write a long UTF string to the buffer
*
* @param string $stream
* @return Zend_Amf_Util_BinaryStream
*/
public function writeLongUtf($stream)
{
$this->writeLong(strlen($stream));
$this->_stream .= $stream;
}
/**
* Read a long numeric value
*
* @return double
*/
public function readLong()
{
$long = ($this->readByte() << 24) + ($this->readByte() << 16) + ($this->readByte() << 8) + $this->readByte();
return $long;
}
/**
* Write long numeric value to output stream
*
* @param int|string $stream
* @return Zend_Amf_Util_BinaryStream
*/
public function writeLong($stream)
{
$this->_stream .= pack("N",$stream);
return $this;
}
/**
* Read a 16 bit unsigned short.
*
* @todo This could use the unpack() w/ S,n, or v
* @return double
*/
public function readUnsignedShort()
{
$byte1 = $this->readByte();
$byte2 = $this->readByte();
$short = (($byte1 << 8) | $byte2);
return $short;
}
/**
* Reads an IEEE 754 double-precision floating point number from the data stream.
*
* @return double Floating point number
*/
public function readDouble()
{
$bytes = substr($this->_stream, $this->_needle, 8);
$this->_needle += 8;
$double = unpack("dflt", strrev($bytes));
return $double['flt'];
}
/**
* Writes an IEEE 754 double-precision floating point number from the data stream.
*
* @param string|double $stream
* @return Zend_Amf_Util_BinaryStream
*/
public function writeDouble($stream)
{
$stream = pack("d", $stream);
if ($this->_bigEndian) {
$stream = strrev($stream);
}
$this->_stream .= $stream;
return $this;
}
}
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