Initial commit

src/Shm/SharedMemoryBlock.php

@@ -0,0 +1,99 @@
+<?php
+
+namespace NoccyLabs\Ipc\Shm;
+
+use NoccyLabs\Ipc\Key\KeyInterface;
+
+/**
+ * A block of shared memory that can be read and write like a string buffer
+ * 
+ * 
+ */
+class SharedMemoryBlock 
+{
+
+    const FLAG_ACCESS = "a";
+    const FLAG_CREATE = "c";
+    const FLAG_WRITE = "w";
+    const FLAG_NEW = "n";
+
+    protected $resource;
+
+    /**
+     * Constructor
+     *
+     * @param KeyInterface $key
+     * @param string $flags
+     * @param integer $memsize
+     * @param integer $perm
+     */
+    public function __construct(KeyInterface $key, string $flags, int $memsize, int $perm = 0666)
+    {
+        if (!($shm_resource = shmop_open($key->getKey(), $memsize, $perm))) {
+            throw new \RuntimeException("Unable to attach shm resource {$key}");
+        }
+        
+        $this->resource = $shm_resource;
+    }
+
+    /**
+     * Destructor
+     */
+    public function __destruct()
+    {
+        if (!$this->resource) {
+            return;
+        }
+        shmop_close($this->resource);
+    }
+
+    /**
+     * Destroy the memory block
+     *
+     * @return void
+     */
+    public function destroy()
+    {
+        shmop_delete($this->resource);
+        shmop_close($this->resource);
+        $this->resource = null;
+    }
+
+    /**
+     * Read bytes from the shared block
+     *
+     * @param integer $length
+     * @param integer $offset
+     * @return mixed
+     */
+    public function read($length=0, $offset=0)
+    {
+        if ($length == 0) {
+            $length = shmop_size($this->resource) - $offset;
+        }
+        return shmop_read($this->resource, $offset, $length);
+    }
+
+    /**
+     * Write bytes to the shared block
+     *
+     * @param mixed $data
+     * @param integer $offset
+     * @return integer
+     */
+    public function write($data, $offset=0):int
+    {
+        return shmop_write($this->resource, $data, $offset);
+    }
+
+    /**
+     * Get the size of the memory block
+     *
+     * @return integer
+     */
+    public function getSize():int
+    {
+        return shmop_size($this->resource);
+    }
+
+}