source: trunk/eraser6/Eraser.Util/NativeMethods/Kernel.cs @ 1841

/* 
 * $Id$
 * Copyright 2008-2010 The Eraser Project
 * Original Author: Joel Low <lowjoel@users.sourceforge.net>
 * Modified By:
 * 
 * This file is part of Eraser.
 * 
 * Eraser is free software: you can redistribute it and/or modify it under the
 * terms of the GNU General Public License as published by the Free Software
 * Foundation, either version 3 of the License, or (at your option) any later
 * version.
 * 
 * Eraser is distributed in the hope that it will be useful, but WITHOUT ANY
 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
 * A PARTICULAR PURPOSE. See the GNU General Public License for more details.
 * 
 * A copy of the GNU General Public License can be found at
 * <http://www.gnu.org/licenses/>.
 */

using System;
using System.Collections.Generic;
using System.Text;
using System.Runtime.InteropServices;
using Microsoft.Win32.SafeHandles;

namespace Eraser.Util
{
    /// <summary>
    /// Stores Kernel32.dll functions, structs and constants.
    /// </summary>
    internal static partial class NativeMethods
    {
        /// <summary>
        /// Deletes an existing file.
        /// </summary>
        /// <param name="lpFileName">The name of the file to be deleted.
        /// 
        /// In the ANSI version of this function, the name is limited to MAX_PATH
        /// characters. To extend this limit to 32,767 wide characters, call
        /// the Unicode version of the function and prepend "\\?\" to the path.
        /// For more information, see Naming a File.</param>
        /// <returns>If the function succeeds, the return value is nonzero.
        /// 
        /// If the function fails, the return value is zero (0). To get extended
        /// error information, call Marshal.GetLastWin32Error().</returns>
        [DllImport("Kernel32.dll", SetLastError = true, CharSet = CharSet.Unicode)]
        [return: MarshalAs(UnmanagedType.Bool)]
        public static extern bool DeleteFile(string lpFileName);

        /// <summary>
        /// Retrieves information about the current system.
        /// </summary>
        /// <param name="lpSystemInfo">A pointer to a SYSTEM_INFO structure that
        /// receives the information.</param>
        [DllImport("Kernel32.dll")]
        public static extern void GetSystemInfo(out SYSTEM_INFO lpSystemInfo);

        /// <summary>
        /// The QueryPerformanceCounter function retrieves the current value of
        /// the high-resolution performance counter.
        /// </summary>
        /// <param name="lpPerformanceCount">[out] Pointer to a variable that receives
        /// the current performance-counter value, in counts.</param>
        /// <returns>If the function succeeds, the return value is nonzero.
        /// 
        /// If the function fails, the return value is zero. To get extended error
        /// information, call Marshal.GetLastWin32Error. </returns>
        [DllImport("Kernel32.dll", SetLastError = true)]
        [return: MarshalAs(UnmanagedType.Bool)]
        public static extern bool QueryPerformanceCounter(out long lpPerformanceCount);

        /// <summary>
        /// Contains information about the current computer system. This includes
        /// the architecture and type of the processor, the number of processors
        /// in the system, the page size, and other such information.
        /// </summary>
        [StructLayout(LayoutKind.Sequential)]
        internal struct SYSTEM_INFO
        {
            /// <summary>
            /// Represents a list of processor architectures.
            /// </summary>
            public enum ProcessorArchitecture : ushort
            {
                /// <summary>
                /// x64 (AMD or Intel).
                /// </summary>
                PROCESSOR_ARCHITECTURE_AMD64 = 9,

                /// <summary>
                /// Intel Itanium Processor Family (IPF).
                /// </summary>
                PROCESSOR_ARCHITECTURE_IA64 = 6,

                /// <summary>
                /// x86.
                /// </summary>
                PROCESSOR_ARCHITECTURE_INTEL = 0,

                /// <summary>
                /// Unknown architecture.
                /// </summary>
                PROCESSOR_ARCHITECTURE_UNKNOWN = 0xffff
            }

            /// <summary>
            /// The processor architecture of the installed operating system.
            /// This member can be one of the ProcessorArchitecture values.
            /// </summary>
            public ProcessorArchitecture processorArchitecture;

            /// <summary>
            /// This member is reserved for future use.
            /// </summary>
            private const ushort reserved = 0;

            /// <summary>
            /// The page size and the granularity of page protection and commitment.
            /// This is the page size used by the VirtualAlloc function.
            /// </summary>
            public uint pageSize;

            /// <summary>
            /// A pointer to the lowest memory address accessible to applications
            /// and dynamic-link libraries (DLLs).
            /// </summary>
            public IntPtr minimumApplicationAddress;

            /// <summary>
            /// A pointer to the highest memory address accessible to applications
            /// and DLLs.
            /// </summary>
            public IntPtr maximumApplicationAddress;

            /// <summary>
            /// A mask representing the set of processors configured into the system.
            /// Bit 0 is processor 0; bit 31 is processor 31.
            /// </summary>
            public IntPtr activeProcessorMask;

            /// <summary>
            /// The number of processors in the system.
            /// </summary>
            public uint numberOfProcessors;

            /// <summary>
            /// An obsolete member that is retained for compatibility. Use the
            /// wProcessorArchitecture, wProcessorLevel, and wProcessorRevision
            /// members to determine the type of processor.
            /// Name                        Value
            /// PROCESSOR_INTEL_386         386
            /// PROCESSOR_INTEL_486         486
            /// PROCESSOR_INTEL_PENTIUM     586
            /// PROCESSOR_INTEL_IA64        2200
            /// PROCESSOR_AMD_X8664         8664
            /// </summary>
            public uint processorType;

            /// <summary>
            /// The granularity for the starting address at which virtual memory
            /// can be allocated. For more information, see VirtualAlloc.
            /// </summary>
            public uint allocationGranularity;

            /// <summary>
            /// The architecture-dependent processor level. It should be used only
            /// for display purposes. To determine the feature set of a processor,
            /// use the IsProcessorFeaturePresent function.
            /// 
            /// If wProcessorArchitecture is PROCESSOR_ARCHITECTURE_INTEL, wProcessorLevel
            /// is defined by the CPU vendor.
            /// If wProcessorArchitecture is PROCESSOR_ARCHITECTURE_IA64, wProcessorLevel
            /// is set to 1.
            /// </summary>
            public ushort processorLevel;

            /// <summary>
            /// The architecture-dependent processor revision. The following table
            /// shows how the revision value is assembled for each type of
            /// processor architecture.
            /// 
            /// Processor                   Value
            /// Intel Pentium, Cyrix        The high byte is the model and the
            /// or NextGen 586              low byte is the stepping. For example,
            ///                             if the value is xxyy, the model number
            ///                             and stepping can be displayed as follows:
            ///                             Model xx, Stepping yy
            /// Intel 80386 or 80486        A value of the form xxyz.
            ///                             If xx is equal to 0xFF, y - 0xA is the model
            ///                             number, and z is the stepping identifier.
            /// 
            ///                             If xx is not equal to 0xFF, xx + 'A'
            ///                             is the stepping letter and yz is the minor stepping.
            /// </summary>
            public ushort processorRevision;
        }

        [DllImport("Kernel32.dll")]
        public static extern EXECUTION_STATE SetThreadExecutionState(EXECUTION_STATE esFlags);

        [Flags]
        public enum EXECUTION_STATE : uint
        {
            ES_AWAYMODE_REQUIRED = 0x00000040,
            ES_CONTINUOUS = 0x80000000,
            ES_DISPLAY_REQUIRED = 0x00000002,
            ES_SYSTEM_REQUIRED = 0x00000001,
            ES_USER_PRESENT = 0x00000004
        }

        /// <summary>
        /// Allocates a new console for the calling process.
        /// </summary>
        /// <returns>If the function succeeds, the return value is nonzero.
        /// 
        /// If the function fails, the return value is zero. To get extended error
        /// information, call Marshal.GetLastWin32Error.</returns>
        /// <remarks>A process can be associated with only one console, so the AllocConsole
        /// function fails if the calling process already has a console. A process can
        /// use the FreeConsole function to detach itself from its current console, then
        /// it can call AllocConsole to create a new console or AttachConsole to attach
        /// to another console.
        /// 
        /// If the calling process creates a child process, the child inherits the
        /// new console.
        /// 
        /// AllocConsole initializes standard input, standard output, and standard error
        /// handles for the new console. The standard input handle is a handle to the
        /// console's input buffer, and the standard output and standard error handles
        /// are handles to the console's screen buffer. To retrieve these handles, use
        /// the GetStdHandle function.
        /// 
        /// This function is primarily used by graphical user interface (GUI) application
        /// to create a console window. GUI applications are initialized without a
        /// console. Console applications are initialized with a console, unless they
        /// are created as detached processes (by calling the CreateProcess function
        /// with the DETACHED_PROCESS flag).</remarks>
        [DllImport("Kernel32.dll", SetLastError = true)]
        [return: MarshalAs(UnmanagedType.Bool)]
        public static extern bool AllocConsole();

        /// <summary>
        /// Detaches the calling process from its console.
        /// </summary>
        /// <returns>If the function succeeds, the return value is nonzero.
        /// 
        /// If the function fails, the return value is zero. To get extended error
        /// information, call Marshal.GetLastWin32Error.</returns>
        /// <remarks>A process can be attached to at most one console. If the calling
        /// process is not already attached to a console, the error code returned is
        /// ERROR_INVALID_PARAMETER (87).
        /// 
        /// A process can use the FreeConsole function to detach itself from its
        /// console. If other processes share the console, the console is not destroyed,
        /// but the process that called FreeConsole cannot refer to it. A console is
        /// closed when the last process attached to it terminates or calls FreeConsole.
        /// After a process calls FreeConsole, it can call the AllocConsole function to
        /// create a new console or AttachConsole to attach to another console.</remarks>
        [DllImport("Kernel32.dll", SetLastError = true)]
        [return: MarshalAs(UnmanagedType.Bool)]
        public static extern bool FreeConsole();

        /// <summary>
        /// The CreateFile function creates or opens a file, file stream, directory,
        /// physical disk, volume, console buffer, tape drive, communications resource,
        /// mailslot, or named pipe. The function returns a handle that can be used
        /// to access an object.
        /// </summary>
        /// <param name="FileName"></param>
        /// <param name="DesiredAccess"> access to the object, which can be read,
        /// write, or both</param>
        /// <param name="ShareMode">The sharing mode of an object, which can be
        /// read, write, both, or none</param>
        /// <param name="SecurityAttributes">A pointer to a SECURITY_ATTRIBUTES
        /// structure that determines whether or not the returned handle can be
        /// inherited by child processes. Can be null</param>
        /// <param name="CreationDisposition">An action to take on files that exist
        /// and do not exist</param>
        /// <param name="FlagsAndAttributes">The file attributes and flags.</param>
        /// <param name="hTemplateFile">A handle to a template file with the
        /// GENERIC_READ access right. The template file supplies file attributes
        /// and extended attributes for the file that is being created. This
        /// parameter can be null</param>
        /// <returns>If the function succeeds, the return value is an open handle
        /// to a specified file. If a specified file exists before the function
        /// all and dwCreationDisposition is CREATE_ALWAYS or OPEN_ALWAYS, a call
        /// to GetLastError returns ERROR_ALREADY_EXISTS, even when the function
        /// succeeds. If a file does not exist before the call, GetLastError
        /// returns 0.
        /// 
        /// If the function fails, the return value is INVALID_HANDLE_VALUE.
        /// To get extended error information, call Marshal.GetLastWin32Error().</returns>
        [DllImport("Kernel32.dll", SetLastError = true, CharSet = CharSet.Unicode)]
        public static extern SafeFileHandle CreateFile(string lpFileName, uint dwDesiredAccess,
            uint dwShareMode, IntPtr SecurityAttributes, uint dwCreationDisposition,
            uint dwFlagsAndAttributes, IntPtr hTemplateFile);

        public const uint FILE_READ_ATTRIBUTES = 0x0080;
        public const uint GENERIC_READ = 0x80000000;
        public const uint GENERIC_WRITE = 0x40000000;
        public const uint GENERIC_EXECUTE = 0x20000000;
        public const uint GENERIC_ALL = 0x10000000;

        public const uint FILE_SHARE_READ = 0x00000001;
        public const uint FILE_SHARE_WRITE = 0x00000002;
        public const uint FILE_SHARE_DELETE = 0x00000004;

        public const uint CREATE_NEW = 1;
        public const uint CREATE_ALWAYS = 2;
        public const uint OPEN_EXISTING = 3;
        public const uint OPEN_ALWAYS = 4;
        public const uint TRUNCATE_EXISTING = 5;

        public const uint FILE_FLAG_WRITE_THROUGH = 0x80000000;
        public const uint FILE_FLAG_OVERLAPPED = 0x40000000;
        public const uint FILE_FLAG_NO_BUFFERING = 0x20000000;
        public const uint FILE_FLAG_RANDOM_ACCESS = 0x10000000;
        public const uint FILE_FLAG_SEQUENTIAL_SCAN = 0x08000000;
        public const uint FILE_FLAG_DELETE_ON_CLOSE = 0x04000000;
        public const uint FILE_FLAG_BACKUP_SEMANTICS = 0x02000000;
        public const uint FILE_FLAG_POSIX_SEMANTICS = 0x01000000;
        public const uint FILE_FLAG_OPEN_REPARSE_POINT = 0x00200000;
        public const uint FILE_FLAG_OPEN_NO_RECALL = 0x00100000;
        public const uint FILE_FLAG_FIRST_PIPE_INSTANCE = 0x00080000;

        [DllImport("Kernel32.dll", SetLastError = true)]
        [return: MarshalAs(UnmanagedType.Bool)]
        public extern static bool DeviceIoControl(SafeFileHandle hDevice,
            uint dwIoControlCode, IntPtr lpInBuffer, uint nInBufferSize,
            out ushort lpOutBuffer, uint nOutBufferSize, out uint lpBytesReturned,
            IntPtr lpOverlapped);

        [DllImport("Kernel32.dll", SetLastError = true)]
        [return: MarshalAs(UnmanagedType.Bool)]
        public extern static bool DeviceIoControl(SafeFileHandle hDevice,
            uint dwIoControlCode, ref ushort lpInBuffer, uint nInBufferSize,
            IntPtr lpOutBuffer, uint nOutBufferSize, out uint lpBytesReturned,
            IntPtr lpOverlapped);

        public const uint FSCTL_GET_COMPRESSION = 0x9003C;
        public const uint FSCTL_SET_COMPRESSION = 0x9C040;
        public const ushort COMPRESSION_FORMAT_NONE = 0x0000;
        public const ushort COMPRESSION_FORMAT_DEFAULT = 0x0001;

        [DllImport("Kernel32.dll", SetLastError = true)]
        [return: MarshalAs(UnmanagedType.Bool)]
        public extern static bool DeviceIoControl(SafeFileHandle hDevice,
            uint dwIoControlCode, IntPtr lpInBuffer, uint nInBufferSize,
            IntPtr lpOutBuffer, uint nOutBufferSize, out uint lpBytesReturned,
            IntPtr lpOverlapped);

        public const uint FSCTL_LOCK_VOLUME = 0x90018;
        public const uint FSCTL_UNLOCK_VOLUME = 0x9001C;

        [DllImport("Kernel32.dll", SetLastError = true)]
        [return: MarshalAs(UnmanagedType.Bool)]
        public extern static bool DeviceIoControl(SafeFileHandle hDevice,
            uint dwIoControlCode, IntPtr lpInBuffer, uint nInBufferSize,
            out DiskPerformanceInfoInternal lpOutBuffer, uint nOutBufferSize,
            out uint lpBytesReturned, IntPtr lpOverlapped);

        public const uint IOCTL_DISK_PERFORMANCE = ((0x00000007) << 16) | ((0x0008) << 2);

        [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
        public struct DiskPerformanceInfoInternal
        {
            public long BytesRead;
            public long BytesWritten;
            public long ReadTime;
            public long WriteTime;
            public long IdleTime;
            public uint ReadCount;
            public uint WriteCount;
            public uint QueueDepth;
            public uint SplitCount;
            public long QueryTime;
            public uint StorageDeviceNumber;

            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 8)]
            public string StorageManagerName;
        }

        [DllImport("Kernel32.dll", CharSet = CharSet.Unicode)]
        [return: MarshalAs(UnmanagedType.Bool)]
        public static extern bool DeviceIoControl(SafeFileHandle hDevice,
            uint dwIoControlCode, IntPtr lpInBuffer, uint nInBufferSize,
            out NTFS_VOLUME_DATA_BUFFER lpOutBuffer, uint nOutBufferSize,
            out uint lpBytesReturned, IntPtr lpOverlapped);

        /// <summary>
        /// Retrieves information about the specified NTFS file system volume.
        /// </summary>
        public const int FSCTL_GET_NTFS_VOLUME_DATA = (9 << 16) | (25 << 2);

        /// <summary>
        /// Retrieves a set of FAT file system attributes for a specified file or
        /// directory.
        /// </summary>
        /// <param name="lpFileName">The name of the file or directory.</param>
        /// <returns>If the function succeeds, the return value contains the attributes
        /// of the specified file or directory.
        /// 
        /// If the function fails, the return value is INVALID_FILE_ATTRIBUTES.
        /// To get extended error information, call Marshal.GetLastWin32Error.
        /// 
        /// The attributes can be one or more of the FILE_ATTRIBUTE_* values.</returns>
        [DllImport("Kernel32.dll", SetLastError = true, CharSet = CharSet.Unicode)]
        public static extern uint GetFileAttributes(string lpFileName);

        /// <summary>
        /// Sets the attributes for a file or directory.
        /// </summary>
        /// <param name="lpFileName">The name of the file whose attributes are
        /// to be set.</param>
        /// <param name="dwFileAttributes">The file attributes to set for the file.
        /// This parameter can be one or more of the FILE_ATTRIBUTE_* values.
        /// However, all other values override FILE_ATTRIBUTE_NORMAL.</param>
        /// <returns>If the function succeeds, the return value is nonzero.
        /// 
        /// If the function fails, the return value is zero. To get extended error
        /// information, call Marshal.GetLastWin32Error.</returns>
        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2205:UseManagedEquivalentsOfWin32Api")]
        [DllImport("Kernel32.dll", SetLastError = true, CharSet = CharSet.Unicode)]
        [return: MarshalAs(UnmanagedType.Bool)]
        public static extern bool SetFileAttributes(string lpFileName,
            uint dwFileAttributes);

        /// <summary>
        /// Retrieves the size of the specified file.
        /// </summary>
        /// <param name="hFile">A handle to the file. The handle must have been
        /// created with either the GENERIC_READ or GENERIC_WRITE access right.
        /// For more information, see File Security and Access Rights.</param>
        /// <param name="lpFileSize">A reference to a long that receives the file
        /// size, in bytes.</param>
        /// <returns>If the function succeeds, the return value is nonzero.
        /// 
        /// If the function fails, the return value is zero. To get extended error
        /// information, call Marshal.GetLastWin32Error.</returns>
        [DllImport("Kernel32.dll", SetLastError = true)]
        [return: MarshalAs(UnmanagedType.Bool)]
        public static extern bool GetFileSizeEx(SafeFileHandle hFile, out long lpFileSize);

        /// <summary>
        /// Retrieves the date and time that a file or directory was created, last
        /// accessed, and last modified.
        /// </summary>
        /// <param name="hFile">A handle to the file or directory for which dates
        /// and times are to be retrieved. The handle must have been created using
        /// the CreateFile function with the GENERIC_READ access right. For more
        /// information, see File Security and Access Rights.</param>
        /// <param name="lpCreationTime">A pointer to a FILETIME structure to
        /// receive the date and time the file or directory was created. This
        /// parameter can be NULL if the application does not require this
        /// information.</param>
        /// <param name="lpLastAccessTime">A pointer to a FILETIME structure to
        /// receive the date and time the file or directory was last accessed. The
        /// last access time includes the last time the file or directory was
        /// written to, read from, or, in the case of executable files, run. This
        /// parameter can be NULL if the application does not require this
        /// information.</param>
        /// <param name="lpLastWriteTime">A pointer to a FILETIME structure to
        /// receive the date and time the file or directory was last written to,
        /// truncated, or overwritten (for example, with WriteFile or SetEndOfFile).
        /// This date and time is not updated when file attributes or security
        /// descriptors are changed. This parameter can be NULL if the application
        /// does not require this information.</param>
        /// <returns>If the function succeeds, the return value is nonzero.
        /// 
        /// If the function fails, the return value is zero. To get extended error
        /// information, call Marshal.GetLastWin32Error().</returns>
        [DllImport("Kernel32.dll", SetLastError = true)]
        [return: MarshalAs(UnmanagedType.Bool)]
        public static extern bool GetFileTime(SafeFileHandle hFile,
            out System.Runtime.InteropServices.ComTypes.FILETIME lpCreationTime,
            out System.Runtime.InteropServices.ComTypes.FILETIME lpLastAccessTime,
            out System.Runtime.InteropServices.ComTypes.FILETIME lpLastWriteTime);

        /// <summary>
        /// Sets the date and time that the specified file or directory was created,
        /// last accessed, or last modified.
        /// </summary>
        /// <param name="hFile">A handle to the file or directory. The handle must
        /// have been created using the CreateFile function with the
        /// FILE_WRITE_ATTRIBUTES access right. For more information, see File
        /// Security and Access Rights.</param>
        /// <param name="lpCreationTime">A pointer to a FILETIME structure that
        /// contains the new creation date and time for the file or directory.
        /// This parameter can be NULL if the application does not need to change
        /// this information.</param>
        /// <param name="lpLastAccessTime">A pointer to a FILETIME structure that
        /// contains the new last access date and time for the file or directory.
        /// The last access time includes the last time the file or directory was
        /// written to, read from, or (in the case of executable files) run. This
        /// parameter can be NULL if the application does not need to change this
        /// information.
        /// 
        /// To preserve the existing last access time for a file even after accessing
        /// a file, call SetFileTime immediately after opening the file handle
        /// with this parameter's FILETIME structure members initialized to
        /// 0xFFFFFFFF.</param>
        /// <param name="lpLastWriteTime">A pointer to a FILETIME structure that
        /// contains the new last modified date and time for the file or directory.
        /// This parameter can be NULL if the application does not need to change
        /// this information.</param>
        /// <returns>If the function succeeds, the return value is nonzero.
        /// 
        /// If the function fails, the return value is zero. To get extended error
        /// information, call GetLastError.</returns>
        [DllImport("Kernel32.dll", SetLastError = true)]
        [return: MarshalAs(UnmanagedType.Bool)]
        public static extern bool SetFileTime(SafeFileHandle hFile,
            ref System.Runtime.InteropServices.ComTypes.FILETIME lpCreationTime,
            ref System.Runtime.InteropServices.ComTypes.FILETIME lpLastAccessTime,
            ref System.Runtime.InteropServices.ComTypes.FILETIME lpLastWriteTime);

        /// <summary>
        /// Retrieves the name of a volume on a computer. FindFirstVolume is used
        /// to begin scanning the volumes of a computer.
        /// </summary>
        /// <param name="lpszVolumeName">A pointer to a buffer that receives a
        /// null-terminated string that specifies the unique volume name of the
        /// first volume found.</param>
        /// <param name="cchBufferLength">The length of the buffer to receive the
        /// name, in TCHARs.</param>
        /// <returns>If the function succeeds, the return value is a search handle
        /// used in a subsequent call to the FindNextVolume and FindVolumeClose
        /// functions.
        /// 
        /// If the function fails to find any volumes, the return value is the
        /// INVALID_HANDLE_VALUE error code. To get extended error information,
        /// call GetLastError.</returns>
        [DllImport("Kernel32.dll", SetLastError = true, CharSet = CharSet.Unicode)]
        public static extern SafeFileHandle FindFirstVolume(StringBuilder lpszVolumeName,
            uint cchBufferLength);

        /// <summary>
        /// Continues a volume search started by a call to the FindFirstVolume
        /// function. FindNextVolume finds one volume per call.
        /// </summary>
        /// <param name="hFindVolume">The volume search handle returned by a previous
        /// call to the FindFirstVolume function.</param>
        /// <param name="lpszVolumeName">A pointer to a string that receives the
        /// unique volume name found.</param>
        /// <param name="cchBufferLength">The length of the buffer that receives
        /// the name, in TCHARs.</param>
        /// <returns>If the function succeeds, the return value is nonzero.
        /// 
        /// If the function fails, the return value is zero. To get extended error
        /// information, call GetLastError. If no matching files can be found, the
        /// GetLastError function returns the ERROR_NO_MORE_FILES error code. In
        /// that case, close the search with the FindVolumeClose function.</returns>
        [DllImport("Kernel32.dll", SetLastError = true, CharSet = CharSet.Unicode)]
        [return: MarshalAs(UnmanagedType.Bool)]
        public static extern bool FindNextVolume(SafeHandle hFindVolume,
            StringBuilder lpszVolumeName, uint cchBufferLength);

        /// <summary>
        /// Closes the specified volume search handle. The FindFirstVolume and
        /// FindNextVolume functions use this search handle to locate volumes.
        /// </summary>
        /// <param name="hFindVolume">The volume search handle to be closed. This
        /// handle must have been previously opened by the FindFirstVolume function.</param>
        /// <returns>If the function succeeds, the return value is nonzero.
        /// 
        /// If the function fails, the return value is zero. To get extended error
        /// information, call GetLastError.</returns>
        [DllImport("Kernel32.dll", SetLastError = true)]
        [return: MarshalAs(UnmanagedType.Bool)]
        public static extern bool FindVolumeClose(SafeHandle hFindVolume);

        /// <summary>
        /// Retrieves the name of a volume mount point on the specified volume.
        /// FindFirstVolumeMountPoint is used to begin scanning the volume mount
        /// points on a volume.
        /// </summary>
        /// <param name="lpszRootPathName">The unique volume name of the volume
        /// to scan for volume mount points. A trailing backslash is required.</param>
        /// <param name="lpszVolumeMountPoint">A pointer to a buffer that receives
        /// the name of the first volume mount point found.</param>
        /// <param name="cchBufferLength">The length of the buffer that receives
        /// the volume mount point name, in TCHARs.</param>
        /// <returns>If the function succeeds, the return value is a search handle
        /// used in a subsequent call to the FindNextVolumeMountPoint and
        /// FindVolumeMountPointClose functions.
        /// 
        /// If the function fails to find a volume mount point on the volume, the
        /// return value is the INVALID_HANDLE_VALUE error code. To get extended
        /// error information, call GetLastError.</returns>
        [DllImport("Kernel32.dll", SetLastError = true, CharSet = CharSet.Unicode)]
        public static extern SafeFileHandle FindFirstVolumeMountPoint(
            string lpszRootPathName, StringBuilder lpszVolumeMountPoint,
            uint cchBufferLength);

        /// <summary>
        /// Continues a volume mount point search started by a call to the
        /// FindFirstVolumeMountPoint function. FindNextVolumeMountPoint finds one
        /// volume mount point per call.
        /// </summary>
        /// <param name="hFindVolumeMountPoint">A mount-point search handle returned
        /// by a previous call to the FindFirstVolumeMountPoint function.</param>
        /// <param name="lpszVolumeMountPoint">A pointer to a buffer that receives
        /// the name of the volume mount point found.</param>
        /// <param name="cchBufferLength">The length of the buffer that receives
        /// the names, in TCHARs.</param>
        /// <returns>If the function succeeds, the return value is nonzero.
        /// 
        /// If the function fails, the return value is zero. To get extended error
        /// information, call GetLastError. If no matching files can be found, the
        /// GetLastError function returns the ERROR_NO_MORE_FILES error code. In
        /// that case, close the search with the FindVolumeMountPointClose function.</returns>
        [DllImport("Kernel32.dll", SetLastError = true, CharSet = CharSet.Unicode)]
        [return: MarshalAs(UnmanagedType.Bool)]
        public static extern bool FindNextVolumeMountPoint(
            SafeHandle hFindVolumeMountPoint, StringBuilder lpszVolumeMountPoint,
            uint cchBufferLength);

        /// <summary>
        /// Closes the specified mount-point search handle. The FindFirstVolumeMountPoint
        /// and FindNextVolumeMountPoint  functions use this search handle to locate
        /// volume mount points on a specified volume.
        /// </summary>
        /// <param name="hFindVolumeMountPoint">The mount-point search handle to
        /// be closed. This handle must have been previously opened by the
        /// FindFirstVolumeMountPoint function.</param>
        /// <returns>If the function succeeds, the return value is nonzero.
        ///
        /// If the function fails, the return value is zero. To get extended error
        /// information, call GetLastError.</returns>
        [DllImport("Kernel32.dll", SetLastError = true)]
        [return: MarshalAs(UnmanagedType.Bool)]
        public static extern bool FindVolumeMountPointClose(SafeHandle hFindVolumeMountPoint);

        /// <summary>
        /// Retrieves information about the specified disk, including the amount
        /// of free space on the disk.
        /// 
        /// The GetDiskFreeSpace function cannot report volume sizes that are
        /// greater than 2 gigabytes (GB). To ensure that your application works
        /// with large capacity hard drives, use the GetDiskFreeSpaceEx function.
        /// </summary>
        /// <param name="lpRootPathName">The root directory of the disk for which
        /// information is to be returned. If this parameter is NULL, the function
        /// uses the root of the current disk. If this parameter is a UNC name,
        /// it must include a trailing backslash (for example, \\MyServer\MyShare\).
        /// Furthermore, a drive specification must have a trailing backslash
        /// (for example, C:\). The calling application must have FILE_LIST_DIRECTORY
        /// access rights for this directory.</param>
        /// <param name="lpSectorsPerCluster">A pointer to a variable that receives
        /// the number of sectors per cluster.</param>
        /// <param name="lpBytesPerSector">A pointer to a variable that receives
        /// the number of bytes per sector.</param>
        /// <param name="lpNumberOfFreeClusters">A pointer to a variable that
        /// receives the total number of free clusters on the disk that are
        /// available to the user who is associated with the calling thread.
        /// 
        /// If per-user disk quotas are in use, this value may be less than the 
        /// total number of free clusters on the disk.</param>
        /// <param name="lpTotalNumberOfClusters">A pointer to a variable that
        /// receives the total number of clusters on the disk that are available
        /// to the user who is associated with the calling thread.
        /// 
        /// If per-user disk quotas are in use, this value may be less than the
        /// total number of clusters on the disk.</param>
        /// <returns>If the function succeeds, the return value is true. To get
        /// extended error information, call Marshal.GetLastWin32Error().</returns>
        [DllImport("Kernel32.dll", SetLastError = true, CharSet = CharSet.Unicode)]
        [return: MarshalAs(UnmanagedType.Bool)]
        public static extern bool GetDiskFreeSpace(
            string lpRootPathName, out UInt32 lpSectorsPerCluster, out UInt32 lpBytesPerSector,
            out UInt32 lpNumberOfFreeClusters, out UInt32 lpTotalNumberOfClusters);


        /// <summary>
        /// Retrieves information about the amount of space that is available on
        /// a disk volume, which is the total amount of space, the total amount
        /// of free space, and the total amount of free space available to the
        /// user that is associated with the calling thread.
        /// </summary>
        /// <param name="lpDirectoryName">A directory on the disk.
        /// 
        /// If this parameter is NULL, the function uses the root of the current
        /// disk.
        /// 
        /// If this parameter is a UNC name, it must include a trailing backslash,
        /// for example, "\\MyServer\MyShare\".
        /// 
        /// This parameter does not have to specify the root directory on a disk.
        /// The function accepts any directory on a disk.
        /// 
        /// The calling application must have FILE_LIST_DIRECTORY access rights
        /// for this directory.</param>
        /// <param name="lpFreeBytesAvailable">A pointer to a variable that receives
        /// the total number of free bytes on a disk that are available to the
        /// user who is associated with the calling thread.
        /// 
        /// This parameter can be NULL.
        /// 
        /// If per-user quotas are being used, this value may be less than the
        /// total number of free bytes on a disk.</param>
        /// <param name="lpTotalNumberOfBytes">A pointer to a variable that receives
        /// the total number of bytes on a disk that are available to the user who
        /// is associated with the calling thread.
        /// 
        /// This parameter can be NULL.
        /// 
        /// If per-user quotas are being used, this value may be less than the
        /// total number of bytes on a disk.
        /// 
        /// To determine the total number of bytes on a disk or volume, use
        /// IOCTL_DISK_GET_LENGTH_INFO.</param>
        /// <param name="lpTotalNumberOfFreeBytes">A pointer to a variable that
        /// receives the total number of free bytes on a disk.
        /// 
        /// This parameter can be NULL.</param>
        /// <returns>If the function succeeds, the return value is nonzero.
        /// 
        /// If the function fails, the return value is zero (0). To get extended
        /// error information, call GetLastError.</returns>
        [DllImport("Kernel32.dll", SetLastError = true, CharSet = CharSet.Unicode)]
        [return: MarshalAs(UnmanagedType.Bool)]
        public static extern bool GetDiskFreeSpaceEx(
            string lpDirectoryName,
            out UInt64 lpFreeBytesAvailable,
            out UInt64 lpTotalNumberOfBytes,
            out UInt64 lpTotalNumberOfFreeBytes);

        /// <summary>
        /// Determines whether a disk drive is a removable, fixed, CD-ROM, RAM disk,
        /// or network drive.
        /// </summary>
        /// <param name="lpRootPathName">The root directory for the drive.
        /// 
        /// A trailing backslash is required. If this parameter is NULL, the function
        /// uses the root of the current directory.</param>
        /// <returns>The return value specifies the type of drive, which can be
        /// one of the DriveInfo.DriveType values.</returns>
        [DllImport("Kernel32.dll", SetLastError = true, CharSet = CharSet.Unicode)]
        public static extern uint GetDriveType(string lpRootPathName);

        /// <summary>
        /// Retrieves information about the file system and volume associated with
        /// the specified root directory.
        /// 
        /// To specify a handle when retrieving this information, use the
        /// GetVolumeInformationByHandleW function.
        /// 
        /// To retrieve the current compression state of a file or directory, use
        /// FSCTL_GET_COMPRESSION.
        /// </summary>
        /// <param name="lpRootPathName">    A pointer to a string that contains
        /// the root directory of the volume to be described.
        /// 
        /// If this parameter is NULL, the root of the current directory is used.
        /// A trailing backslash is required. For example, you specify
        /// \\MyServer\MyShare as "\\MyServer\MyShare\", or the C drive as "C:\".</param>
        /// <param name="lpVolumeNameBuffer">A pointer to a buffer that receives
        /// the name of a specified volume. The maximum buffer size is MAX_PATH+1.</param>
        /// <param name="nVolumeNameSize">The length of a volume name buffer, in
        /// TCHARs. The maximum buffer size is MAX_PATH+1.
        /// 
        /// This parameter is ignored if the volume name buffer is not supplied.</param>
        /// <param name="lpVolumeSerialNumber">A pointer to a variable that receives
        /// the volume serial number.
        /// 
        /// This parameter can be NULL if the serial number is not required.
        /// 
        /// This function returns the volume serial number that the operating system
        /// assigns when a hard disk is formatted. To programmatically obtain the
        /// hard disk's serial number that the manufacturer assigns, use the
        /// Windows Management Instrumentation (WMI) Win32_PhysicalMedia property
        /// SerialNumber.</param>
        /// <param name="lpMaximumComponentLength">A pointer to a variable that
        /// receives the maximum length, in TCHARs, of a file name component that
        /// a specified file system supports.
        /// 
        /// A file name component is the portion of a file name between backslashes.
        /// 
        /// The value that is stored in the variable that *lpMaximumComponentLength
        /// points to is used to indicate that a specified file system supports
        /// long names. For example, for a FAT file system that supports long names,
        /// the function stores the value 255, rather than the previous 8.3 indicator.
        /// Long names can also be supported on systems that use the NTFS file system.</param>
        /// <param name="lpFileSystemFlags">A pointer to a variable that receives
        /// flags associated with the specified file system.
        /// 
        /// This parameter can be one or more of the FS_FILE* flags. However,
        /// FS_FILE_COMPRESSION and FS_VOL_IS_COMPRESSED are mutually exclusive.</param>
        /// <param name="lpFileSystemNameBuffer">A pointer to a buffer that receives
        /// the name of the file system, for example, the FAT file system or the
        /// NTFS file system. The maximum buffer size is MAX_PATH+1.</param>
        /// <param name="nFileSystemNameSize">The length of the file system name
        /// buffer, in TCHARs. The maximum buffer size is MAX_PATH+1.
        /// 
        /// This parameter is ignored if the file system name buffer is not supplied.</param>
        /// <returns>If all the requested information is retrieved, the return value
        /// is nonzero.
        /// 
        /// 
        /// If not all the requested information is retrieved, the return value is
        /// zero (0). To get extended error information, call GetLastError.</returns>
        [DllImport("Kernel32.dll", SetLastError = true, CharSet = CharSet.Unicode)]
        [return: MarshalAs(UnmanagedType.Bool)]
        public static extern bool GetVolumeInformation(
            string lpRootPathName,
            StringBuilder lpVolumeNameBuffer,
            uint nVolumeNameSize,
            out uint lpVolumeSerialNumber,
            out uint lpMaximumComponentLength,
            out uint lpFileSystemFlags,
            StringBuilder lpFileSystemNameBuffer,
            uint nFileSystemNameSize);

        /// <summary>
        /// Retrieves the unique volume name for the specified volume mount point or root directory.
        /// </summary>
        /// <param name="lpszVolumeMountPoint">The path of a volume mount point (with a trailing
        /// backslash, "\") or a drive letter indicating a root directory (in the
        /// form "D:\").</param>
        /// <param name="lpszVolumeName">A pointer to a string that receives the
        /// volume name. This name is a unique volume name of the form
        /// "\\?\Volume{GUID}\" where GUID is the GUID that identifies the volume.</param>
        /// <param name="cchBufferLength">The length of the output buffer, in TCHARs.
        /// A reasonable size for the buffer to accommodate the largest possible
        /// volume name is 50 characters.</param>
        /// <returns>If the function succeeds, the return value is nonzero.
        /// 
        /// If the function fails, the return value is zero. To get extended
        /// error information, call GetLastError.</returns>
        [DllImport("Kernel32.dll", SetLastError = true, CharSet = CharSet.Unicode)]
        [return: MarshalAs(UnmanagedType.Bool)]
        public static extern bool GetVolumeNameForVolumeMountPoint(
            string lpszVolumeMountPoint, StringBuilder lpszVolumeName,
            uint cchBufferLength);

        /// <summary>
        /// Retrieves a list of path names for the specified volume name.
        /// </summary>
        /// <param name="lpszVolumeName">The volume name.</param>
        /// <param name="lpszVolumePathNames">A pointer to a buffer that receives
        /// the list of volume path names. The list is an array of null-terminated
        /// strings terminated by an additional NULL character. If the buffer is
        /// not large enough to hold the complete list, the buffer holds as much
        /// of the list as possible.</param>
        /// <param name="cchBufferLength">The length of the lpszVolumePathNames
        /// buffer, in TCHARs.</param>
        /// <param name="lpcchReturnLength">If the call is successful, this parameter
        /// is the number of TCHARs copied to the lpszVolumePathNames buffer. Otherwise,
        /// this parameter is the size of the buffer required to hold the complete
        /// list, in TCHARs.</param>
        /// <returns></returns>
        [DllImport("Kernel32.dll", SetLastError = true, CharSet = CharSet.Unicode)]
        [return: MarshalAs(UnmanagedType.Bool)]
        public static extern bool GetVolumePathNamesForVolumeName(
            string lpszVolumeName, StringBuilder lpszVolumePathNames, uint cchBufferLength,
            out uint lpcchReturnLength);

        public const int MaxPath = 260;
        public const int LongPath = 32768;
    }
}