/*

   This Source Code Form is subject to the terms of the Mozilla Public

   License, v. 2.0. If a copy of the MPL was not distributed with this

   file, You can obtain one at http://mozilla.org/MPL/2.0/.

   Copyright (C) 2012 Michael Möller <mmoeller@openhardwaremonitor.org>

 */

 using System.Runtime.InteropServices;

 namespace OpenHardwareMonitor.Hardware.RAM {

   internal class GenericRAM : Hardware {

     private Sensor loadSensor;

     private Sensor usedMemory;

     private Sensor availableMemory;

     public GenericRAM(string name, ISettings settings)

       : base(name, new Identifier("ram"), settings)

     {   

       loadSensor = new Sensor("Memory", 0, SensorType.Load, this, settings);

       ActivateSensor(loadSensor);

       usedMemory = new Sensor("Used Memory", 0, SensorType.Data, this,

         settings);

       ActivateSensor(usedMemory);

       availableMemory = new Sensor("Available Memory", 1, SensorType.Data, this, 

         settings);

       ActivateSensor(availableMemory);

     }

     public override HardwareType HardwareType {

       get {

         return HardwareType.RAM;

       }

     }

     public override void Update() {

       NativeMethods.MemoryStatusEx status = new NativeMethods.MemoryStatusEx();

       status.Length = checked((uint)Marshal.SizeOf(

           typeof(NativeMethods.MemoryStatusEx)));

       if (!NativeMethods.GlobalMemoryStatusEx(ref status))

         return;

       loadSensor.Value = 100.0f -

         (100.0f * status.AvailablePhysicalMemory) /

         status.TotalPhysicalMemory;

       usedMemory.Value = (float)(status.TotalPhysicalMemory 

         - status.AvailablePhysicalMemory) / (1024 * 1024 * 1024);

       availableMemory.Value = (float)status.AvailablePhysicalMemory /

         (1024 * 1024 * 1024);

     }

     private class NativeMethods {

       [StructLayout(LayoutKind.Sequential)]

       public struct MemoryStatusEx {

         public uint Length;

         public uint MemoryLoad;

         public ulong TotalPhysicalMemory;

         public ulong AvailablePhysicalMemory;

         public ulong TotalPageFile;

         public ulong AvailPageFile;

         public ulong TotalVirtual;

         public ulong AvailVirtual;

         public ulong AvailExtendedVirtual;

       }

       [DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]

       [return: MarshalAs(UnmanagedType.Bool)]

       internal static extern bool GlobalMemoryStatusEx(

         ref NativeMethods.MemoryStatusEx buffer);

     }

   }

 }