Programming Memory-Mapped Files with the .NET Framework

using System;
using System.IO;
using System.IO.MemoryMappedFiles;

namespace NetMMFCopyFile
{
    class Program
    {
        static void Main(string[] args)
        {
            int offset = 0;
            int length = 0;
            byte[] buffer;

            if (args.GetLength(0) != 2)
            {
                Console.WriteLine("Usage: NetMMFCopyFile.exe file1 file2");
                return;
            }

            FileInfo fi = new FileInfo(args[0]);
            length = (int)fi.Length;

            // Create unnamed MMF
            using (var mmf1 = MemoryMappedFile.CreateFromFile(args[0], FileMode.OpenOrCreate, null, offset + length))
            {
                // Create reader to MMF
                using (var reader = mmf1.CreateViewAccessor(offset, length, MemoryMappedFileAccess.Read))
                {
                    // Read from MMF
                    buffer = new byte[length];
                    reader.ReadArray<byte>(0, buffer, 0, length);
                }
            }

            // Create disk file
            using (FileStream fs = File.Create(args[1]))
            {
                fs.Close();
            }
 
            // Create unnamed MMF
            using (var mmf2 = MemoryMappedFile.CreateFromFile(args[1], FileMode.Create, null, offset + length))
            {
                // Create writer to MMF
                using (var writer = mmf2.CreateViewAccessor(offset, length, MemoryMappedFileAccess.Write))
                {
                    // Write to MMF
                    writer.WriteArray<byte>(0, buffer, 0, length);
                }
            }
        }
    }
}