/*

   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) 2011 Michael Möller <mmoeller@openhardwaremonitor.org>

 */

 using System;

 using System.ComponentModel;

 using System.Runtime.InteropServices;

 using System.Text;

 namespace OpenHardwareMonitor.Hardware {

   internal static class FirmwareTable {

     public static byte[] GetTable(Provider provider, string table) {

       int id = table[3] << 24 | table[2] << 16 | table[1] << 8 | table[0];

       return GetTable(provider, id);

     }

     public static byte[] GetTable(Provider provider, int table) {

       int size;

       try {

         size = NativeMethods.GetSystemFirmwareTable(provider, table, 

           IntPtr.Zero, 0);

       } catch (DllNotFoundException) { return null; } 

         catch (EntryPointNotFoundException) { return null; }

       if (size <= 0)

         return null;

       IntPtr nativeBuffer = Marshal.AllocHGlobal(size);

       NativeMethods.GetSystemFirmwareTable(provider, table, nativeBuffer, size);

       if (Marshal.GetLastWin32Error() != 0)

         return null;

       byte[] buffer = new byte[size];

       Marshal.Copy(nativeBuffer, buffer, 0, size);

       Marshal.FreeHGlobal(nativeBuffer);

       return buffer;

     }

     public static string[] EnumerateTables(Provider provider) {

       int size;

       try {

         size = NativeMethods.EnumSystemFirmwareTables(

           provider, IntPtr.Zero, 0);

       } catch (DllNotFoundException) { return null; } 

         catch (EntryPointNotFoundException) { return null; }

       IntPtr nativeBuffer = Marshal.AllocHGlobal(size);

       NativeMethods.EnumSystemFirmwareTables(

         provider, nativeBuffer, size);

       byte[] buffer = new byte[size];

       Marshal.Copy(nativeBuffer, buffer, 0, size);

       Marshal.FreeHGlobal(nativeBuffer);

       string[] result = new string[size / 4];

       for (int i = 0; i < result.Length; i++) 

         result[i] = Encoding.ASCII.GetString(buffer, 4 * i, 4);

       return result;

     }

     public enum Provider : int {

       ACPI = (byte)'A' << 24 | (byte)'C' << 16 | (byte)'P' << 8 | (byte)'I',

       FIRM = (byte)'F' << 24 | (byte)'I' << 16 | (byte)'R' << 8 | (byte)'M',

       RSMB = (byte)'R' << 24 | (byte)'S' << 16 | (byte)'M' << 8 | (byte)'B'

     }

     private static class NativeMethods {

       private const string KERNEL = "kernel32.dll";

       [DllImport(KERNEL, CallingConvention = CallingConvention.Winapi,

         SetLastError = true)]

       public static extern int EnumSystemFirmwareTables(

         Provider firmwareTableProviderSignature,

         IntPtr firmwareTableBuffer, int bufferSize);

       [DllImport(KERNEL, CallingConvention = CallingConvention.Winapi,

         SetLastError = true)]

       public static extern int GetSystemFirmwareTable(

         Provider firmwareTableProviderSignature,

         int firmwareTableID, IntPtr firmwareTableBuffer, int bufferSize);

     }

   }

 }