Bytearray.class.php

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<?php
/* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */
 
class Bytearray
{
    private $_byteArray    = array();
 
    private $_bytes   = '';
    
    private $_lastPosition = 0;
    
    private $_position     = 0;
    
    
    
    public function setPosition($position)
    {
        $this->_lastPosition = $this->_position;
        $this->_position     = $position;   
    }
    
 
    public function getPosition()
    {
        return $this->_position;   
    }
    
    
    public function getLastPosition()
    {
        return $this->_lastPosition;   
    }
    
    
    public function writeBytes($bytes, $offset = false, $inject = false)
    {
        // if offset not given - set offset to lastpos + 1 (append)
        if (!$offset) {
            $offset = $this->getPosition();
        }
        
        if ($offset == $this->getPosition()) {
            // offset is current pos (len) +1 so just append!
            $this->_bytes .= $bytes;
            $this->setPosition($offset + strlen($bytes));
                        
        } elseif ($offset > $this->getPosition()) {
            // the offset is larger then current bytes string len
            // fill missing bytes with null-Bytes
            $countFillBytes = $offset - $this->getPosition();
            for ($i = 0; $i < $countFillBytes; $i++) {
                $fillBytes .= pack("H", 0x00);
            }
            $this->_bytes .= $fillBytes;
            $this->_bytes .= $bytes;
            $this->setPosition($offset + strlen($bytes));
            
        } elseif ($offset < strlen($this->_bytes)+1) {
            // we write into existing position in byte string
            // so we check for overwrite (default) || inject into exisiting
            if (!$inject) {
                // we overwrite exisiting bytes
                // we inject bytes into existing bytes
                $bytesB = substr($this->_bytes, 0, $offset-1);
                $bytesA = substr($this->_bytes, ($offset-1)+strlen($bytes), strlen($this->_bytes)-(($offset-1)+strlen($bytes)));              
                $this->_bytes = $bytesB . $bytes . $bytesA;
                $this->setPosition(strlen($this->_bytes));              
                
            } else {
                // we inject bytes into existing bytes
                $bytesB = substr($this->_bytes, 0, $offset-1);
                $bytesA = substr($this->_bytes, $offset-1, strlen($this->_bytes)-($offset-1));              
                $this->_bytes = $bytesB . $bytes . $bytesA;
                $this->setPosition(strlen($this->_bytes) . strlen($bytes));
            }
        }
    } 
 
        
    public function readBytes($offset, $length)
    {
        return substr($this->_bytes, $offset, $length);   
    }
    
    
    public function readAllBytes()
    {
        return $this->_bytes;   
    }     
    
    
    public function readUnsignedInt($offset)
    {
        $length = 4;
        $bytes  = $this->readBytes($offset, $length);
        $bytes  = unpack('N', $bytes);
        return $bytes[count($bytes)];
    }
 
 
    public function readUTFBytes($offset, $length = 4)
    {
        $bytes = $this->readBytes($offset, $length);
        return $bytes;
    }
    
    
    public function readDouble($offset, $length = 8)
    {
        $bytes  = $this->readBytes($offset, $length);
        $bytes  = unpack('d', $bytes);
        return $bytes[count($bytes)];
    }   
        
    
    public function bytesAvailable()
    {
        return strlen($this->_bytes);
    }
}
 
?>