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<?php
/* vim: set expandtab tabstop=4 shiftwidth=4: */
// +----------------------------------------------------------------------+
// | PHP Version 4 |
// +----------------------------------------------------------------------+
// | Copyright (c) 1997-2003 The PHP Group |
// +----------------------------------------------------------------------+
// | This source file is subject to version 2.02 of the PHP license, |
// | that is bundled with this package in the file LICENSE, and is |
// | available at through the world-wide-web at |
// | http://www.php.net/license/2_02.txt. |
// | If you did not receive a copy of the PHP license and are unable to |
// | obtain it through the world-wide-web, please send a note to |
// | license@php.net so we can mail you a copy immediately. |
// +----------------------------------------------------------------------+
// | Authors: David Sklar <sklar@sklar.com> |
// +----------------------------------------------------------------------+
//
// $Id: SHM.php,v 1.2 2003/01/15 22:00:36 sklar Exp $
//
/**
* This class implements a user-space stream that reads/writes shared
* memory. It requires the shmop extension for shared memory access.
*
* Sample Usage:
*
* require_once('Stream/SHM.php');
* stream_register_wrapper('shm','Stream_SHM') or die("can't register shm");
* $shm = fopen('shm://0xabcd:12000','c');
* fwrite($shm, 'One Two Three Four');
* fseek($shm,4,SEEK_SET);
* $two = fread($shm,3); // $two is "Two"
* fclose($shm);
*
* Specify the key of the shared memory segment in decimal or hexadecimal
* after the "shm://" and then optionally, a colon and the size of the
* shared memory segment. If you don't specify a size, the segment size
* defaults to 16384 bytes.
*
* Allowable modes are "a", "c", "w", and "n". For what those modes
* mean, see:
* --> http://www.php.net/manual/en/function.shmop-open.php
*
*
* @author David Sklar <sklar@sklar.com>
* @version 1.0
* @package Stream::SHM
*/
class Stream_SHM {
/**
* position
*
* @var string stream position in the shared memory segment
*/
var $pos = 0;
/**
* shared memory segment key
*
* @var integer key (for shmop_open()) of the segment
*/
var $shm_key;
/**
* shared memory segment size
*
* @var integer size of the shared memory segment (default: 16k)
*/
var $size = 16384;
/**
* shared memory segment handle
* @var resource handle to the segment for the shmop_*() functions
*/
var $shm;
/**
* Stream opener
*
* @param string $path URL-style path to the segment
* @param string $mode mode to open the segment with
* @param integer $options stream options
* @param string &$opened_path (not used)
* @return boolean Stream opened sucessfully?
*/
function stream_open($path, $mode, $options, &$opened_path)
{
$url = parse_url($path);
$this->shm_key = $url['host'];
if ((! intval($this->shm_key)) && (! preg_match('/^0x[0-9a-f]+$/i',
$this->shm_key))) {
if ($options & STREAM_REPORT_ERRORS) {
trigger_error("Stream_SHM::stream_open: $this->shm_key is not a valid shm key.",E_USER_ERROR);
}
return false;
}
if (intval($url['port'])) {
$this->size = intval($url['port']);
}
if (($mode != 'a') && ($mode != 'c') &&
($mode != 'w') && ($mode != 'n')) {
if ($options & STREAM_REPORT_ERRORS) {
trigger_error("Stream_SHM::stream_open: $mode is not a valid mode (must be one of: a c n w)",E_USER_ERROR);
}
return false;
}
if (! ($this->shm = shmop_open($this->shm_key,$mode,0600,$this->size))) {
if ($options & STREAM_REPORT_ERRORS) {
trigger_error('Stream_SHM::stream_open: shmop_open() failed');
}
return false;
}
$this->size = shmop_size($this->shm);
return true;
}
/**
* Stream closer
*
*/
function stream_close()
{
shmop_close($this->shm);
}
/**
* Read from stream
*
* @param integer $count How many bytes to read from the stream
* @return string Data read from the stream
*/
function stream_read($count)
{
// Don't read past the end of the stream
if ($count + $this->pos > $this->size) {
$count = $this->size - $this->pos;
}
$data = shmop_read($this->shm,$this->pos,$count);
$this->pos += strlen($data);
return $data;
}
/**
* Write to stream
*
* @param mixed $data Data to write to the stream
* @return integer Bytes actually written to the stream
*/
function stream_write($data)
{
$count = shmop_write($this->shm,$data,$this->pos);
$this->pos += $count;
return $count;
}
/**
* Check stream end-of-file
*
* @return boolean Is the stream position at the end of the stream?
*/
function stream_eof()
{
return ($this->pos == ($this->size - 1));
}
/**
* Get stream position
*
* @return integer The current position in the stream
*/
function stream_tell()
{
return $this->pos;
}
/**
* Adjust current position in the stream
*
* @param integer $offset How many bytes to move the position
* @param integer $whence Where to start counting from
* @return boolean Was the position adjustment successful?
*/
function stream_seek($offset,$whence)
{
switch ($whence) {
case SEEK_SET:
if (($offset >= 0) && ($offset < $this->size)) {
$this->pos = $offset;
return true;
} else {
return false;
}
break;
case SEEK_CUR:
if (($offset >= 0) && (($this->pos + $offset) < $this->size)) {
$this->pos += $offset;
return true;
} else {
return false;
}
break;
case SEEK_END:
if (($this->size + $offset) >= 0) {
$this->pos = $this->size + $offset;
return true;
} else {
return false;
}
break;
default:
return false;
}
}
/**
* Flush data to the stream
*
* @return boolean Data is always flushed when writing with shmop_write()
*/
function stream_flush()
{
return true;
}
}
?>
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