C # Memory Sharing and memory ing files

Using System;
Using System. Collections. Generic;
Using System. Text;
Using System. Runtime. InteropServices;
Using System. IO;
Using System. Data. SqlClient;

Namespace WinApp
{
Public class Sequence
{
[DllImport ("kernel32.dll")]
Public static extern IntPtr CreateFileMapping (IntPtr hFile, IntPtr lpFileMappingAttributes, uint flProtect, uint dwMaximumSizeHigh,
Uint dwMaximumSizeLow, string lpName );

[DllImport ("kernel32.dll")]
Public static extern IntPtr MapViewOfFile (IntPtr hFileMappingObject, uint
DwDesiredAccess, uint dwFileOffsetHigh, uint dwFileOffsetLow, IntPtr dwNumberOfBytesToMap );

[DllImport ("kernel32.dll")]
Public static extern bool UnmapViewOfFile (IntPtr lpBaseAddress );

[DllImport ("kernel32.dll")]
Public static extern bool CloseHandle (IntPtr hObject );

[DllImport ("kernel32.dll")]
Public static extern IntPtr CreateFile (string lpFileName, int dwDesiredAccess, FileShare dw1_mode, IntPtr securityAttrs,
FileMode dwCreationDisposition, int dwFlagsAndAttributes, IntPtr hTemplateFile );

[DllImport ("kernel32.dll")]
Public static extern uint GetFileSize (IntPtr hFile, IntPtr lpFileSizeHigh );

Public const int GENERIC_READ =-2147483648; // 0x80000000
Public const int GENERIC_WRITE = 0x40000000;
Public const int GENERIC_EXECUTE = 0x20000000;
Public const int GENERIC_ALL = 0x10000000;
Public const int FILE_ATTRIBUTE_NORMAL = 0x80;
Public const int FILE_FLAG_SEQUENTIAL_SCAN = 0x8000000;
Public const int INVALID_HANDLE_VALUE =-1;

Public const int PAGE_NOACCESS = 1;
Public const int PAGE_READONLY = 2;
Public const int PAGE_READWRITE = 4;

Public const int FILE_MAP_COPY = 1;
Public const int FILE_MAP_WRITE = 2;
Public const int FILE_MAP_READ = 4;

Public static string MappingFileRead ()
{
String result = "";
Try
{
IntPtr vFileHandle = CreateFile (@ "c: \ test.txt", GENERIC_READ | GENERIC_WRITE, FileShare. Read | FileShare. Write, IntPtr. Zero, FileMode. Open,
FILE_ATTRIBUTE_NORMAL | FILE_FLAG_SEQUENTIAL_SCAN, IntPtr. Zero );
If (INVALID_HANDLE_VALUE! = (Int) vFileHandle)
{
IntPtr vMappingHandle = CreateFileMapping (vFileHandle, IntPtr. Zero, PAGE_READWRITE, 0, 0 ,"~ MappingTemp ");
If (vMappingHandle! = IntPtr. Zero)
{
IntPtr vHead = MapViewOfFile (vMappingHandle, FILE_MAP_COPY | FILE_MAP_READ | FILE_MAP_WRITE, 0, 0, IntPtr. Zero );
If (vHead! = IntPtr. Zero)
{
Uint vSize = GetFileSize (vFileHandle, IntPtr. Zero );
Byte [] res = new byte [vSize];
Marshal. Copy (vHead, res, 0, (int) vSize );
Result = ASCIIEncoding. Default. GetString (res );
String [] _ str = result. Split ('| ');
Result = _ str [0];
/*
//************************************** *
// _ IntPtr = Marshal. ReadIntPtr (vHead );
Byte [] contentbyte1 = new byte [vSize];
For (int I = 0; I <vSize; I ++)
{
Byte vTemp = Marshal. ReadByte (IntPtr) (int) vHead + I ));
Contentbyte1 [I] = vTemp;
}
Console. WriteLine (ASCIIEncoding. Default. GetString (contentbyte1); // All values
//************************************** *
Byte [] contentbyte = new byte [vSize];
For (int I = 0; I <vSize; I ++)
{
Byte vTemp = Marshal. ReadByte (IntPtr) (int) vHead + I ));
Contentbyte [I] = vTemp;
If (vTemp = '|') // sets the end of the mark to conform
{
Break;
}
}
Console. WriteLine (ASCIIEncoding. Default. GetString (contentbyte); // value to be retrieved
Result = ASCIIEncoding. Default. GetString (contentbyte );
//************************************** *
*/
UnmapViewOfFile (vHead );
}
CloseHandle (vMappingHandle );
}
CloseHandle (vFileHandle );
}

}
Catch
{}
Return result;
}
Public static IntPtr InvalidHandleValue = new IntPtr (-1 );
Public static void MappingFileWrite (string val)
{
Try
{
IntPtr vFileHandle = CreateFile (@ "c: \ test.txt", GENERIC_READ | GENERIC_WRITE, FileShare. Read | FileShare. Write, IntPtr. Zero, FileMode. Open,
FILE_ATTRIBUTE_NORMAL | FILE_FLAG_SEQUENTIAL_SCAN, IntPtr. Zero );
If (INVALID_HANDLE_VALUE! = (Int) vFileHandle)
{
IntPtr vMappingHandle = CreateFileMapping (vFileHandle, IntPtr. Zero, PAGE_READWRITE, 0, (UInt32) (val. Length + 1 ),"~ MappingTemp ");
If (vMappingHandle! = IntPtr. Zero)
{
IntPtr vHead = MapViewOfFile (vMappingHandle, FILE_MAP_COPY | FILE_MAP_READ | FILE_MAP_WRITE, 0, 0, IntPtr. Zero );
If (vHead! = IntPtr. Zero)
{
Byte [] by = ASCIIEncoding. Default. GetBytes (val + "|"); // sets the end of the mark to conform to |
Marshal. Copy (by, 0, vHead, by. Length );
UnmapViewOfFile (vHead );
}
CloseHandle (vMappingHandle );
}
CloseHandle (vFileHandle );
}

}
Catch
{}
}

Public static void MappingWrite1 (string val)
{
Try
{
IntPtr vMappingHandle = CreateFileMapping (InvalidHandleValue, IntPtr. Zero, PAGE_READWRITE, 0, (UInt32) (val. Length + 1 ),"~ MappingTemp ");
If (vMappingHandle! = IntPtr. Zero)
{
IntPtr vHead = MapViewOfFile (vMappingHandle, FILE_MAP_COPY | FILE_MAP_READ | FILE_MAP_WRITE, 0, 0, IntPtr. Zero );
If (vHead! = IntPtr. Zero)
{
Byte [] by = ASCIIEncoding. Default. GetBytes (val + "|"); // sets the end of the mark to conform to |
Marshal. Copy (by, 0, vHead, by. Length );
UnmapViewOfFile (vHead );
}
// CloseHandle (vMappingHandle );
}

}
Catch
{}
}
Public static string MappingRead1 ()
{
String result = "";
Try
{
IntPtr vMappingHandle = CreateFileMapping (InvalidHandleValue, IntPtr. Zero, PAGE_READWRITE, 0, 7 ,"~ MappingTemp ");
If (vMappingHandle! = IntPtr. Zero)
{
IntPtr vHead = MapViewOfFile (vMappingHandle, FILE_MAP_COPY | FILE_MAP_READ | FILE_MAP_WRITE, 0, 0, IntPtr. Zero );
If (vHead! = IntPtr. Zero)
{
Byte [] bytData = new byte [7];
Marshal. Copy (vHead, bytData, 0, 7 );
Result = ASCIIEncoding. Default. GetString (bytData );
UnmapViewOfFile (vHead );
}
CloseHandle (vMappingHandle );
}
}
Catch
{
}
Return result;
}
}
}