<?php /** * Using shared Memory for PHP loop memory queue implementation * Supports multiple processes to support storage of various data types * Note: Complete the team or outbound operation, use Unset () as soon as possible to release the critical section * * @author wangbinandi@gmail.com * @created 2009-12-23 */ Class Shmqueue { Private $maxQSize = 0; Maximum Queue Length Private $front = 0; Team Head pointer Private $rear = 0; Team Tail pointer Private $blockSize = 256; Size of block (byte) Private $memSize = 25600; Maximum shared memory (byte) Private $shmId = 0; Private $filePtr = './shmq.ptr '; Private $semId = 0; Public Function __construct () { $shmkey = Ftok (__file__, ' t '); $this->shmid = Shmop_open ($shmkey, "C", 0644, $this->memsize); $this->maxqsize = $this->memsize/$this->blocksize; A signal quantity. $this->semid = Sem_get ($shmkey, 1); Sem_acquire ($this->semid); Apply for entry into critical section $this->init (); } Private Function init () { if (file_exists ($this->fileptr)) { $contents = file_get_contents ($this->fileptr); $data = Explode (' | ', $contents); if (isset ($data [0]) && isset ($data [1])) { $this->front = (int) $data [0]; $this->rear = (int) $data [1]; } } } Public Function GetLength () { Return (($this->rear-$this->front + $this->memsize)% ($this->memsize))/$this->blocksize; } Public Function EnQueue ($value) { if ($this->ptrinc ($this->rear) = = $this->front) {//Team full return false; } $data = $this->encode ($value); Shmop_write ($this->shmid, $data, $this->rear); $this->rear = $this->ptrinc ($this->rear); return true; } Public Function dequeue () { if ($this->front = = $this->rear) {//Team empty return false; } $value = Shmop_read ($this->shmid, $this->front, $this->blocksize-1); $this->front = $this->ptrinc ($this->front); return $this->decode ($value); } Private Function Ptrinc ($ptr) { Return ($ptr + $this->blocksize)% ($this->memsize); } Private function encode ($value) { $data = Serialize ($value). "__eof"; Echo '; echo strlen ($data); Echo '; Echo $this->blocksize-1; Echo '; if (strlen ($data) > $this->blocksize-1) { throw new Exception (strlen ($data). "is overload block size!"); } return $data; } Private function decode ($value) { $data = Explode ("__eof", $value); return unserialize ($data [0]); } Public Function __destruct () { $data = $this->front. '|' . $this->rear; File_put_contents ($this->fileptr, $data); Sem_release ($this->semid); Out of the critical section, releasing the signal volume } } /* Enter the team operation $SHMQ = new Shmqueue (); $data = ' test data '; $SHMQ->enqueue ($data); Unset ($SHMQ); Out Team operation $SHMQ = new Shmqueue (); $data = $shmq->dequeue (); Unset ($SHMQ); */ ?> |