/*

  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);

    }

  }

}