Лаба

using Microsoft.Win32.SafeHandles;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Diagnostics;
using System.Drawing;
using System.IO;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace Лаба__4
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        private string fileSrc = "test.txt";
        private string fileDest = "test_copy.txt";

        public class Win32
        {
            IntPtr handle;
            const uint GENERIC_READ = 0x80000000;
            public const uint GENERIC_WRITE = 0x40000000;
            const uint OPEN_EXISTING = 3;
            const uint CREATE_ALWAYS = 2;

            [DllImport("kernel32.dll", SetLastError = true, ThrowOnUnmappableChar = true, CharSet = CharSet.Unicode)]
            public static extern unsafe IntPtr CreateFile
            (
                string FileName,          // file name
                uint DesiredAccess,       // access mode
                uint ShareMode,           // share mode
                uint SecurityAttributes,  // Security Attributes
                uint CreationDisposition, // how to create
                uint FlagsAndAttributes,  // file attributes
                int hTemplateFile         // handle to template file
            );

            [DllImport("kernel32.dll", SetLastError = true)]
            public static extern unsafe bool ReadFile
            (
                IntPtr hFile,      // handle to file
                void* pBuffer,            // data buffer
                int NumberOfBytesToRead,  // number of bytes to read
                int* pNumberOfBytesRead,  // number of bytes read
                int Overlapped            // overlapped buffer
            );

            [DllImport("kernel32.dll", SetLastError = true)]
            public static extern unsafe bool WriteFile(
                IntPtr hFile,
                void* lpBuffer,
                int nNumberOfBytesToWrite,
                int* lpNumberOfBytesWritten,
                int lpOverlapped);

            [DllImport("kernel32.dll", SetLastError = true)]
            public static extern unsafe bool CloseHandle
            (
                IntPtr hObject // handle to object
            );

            public bool Open(string FileName)
            {
                // open the existing file for reading
                handle = CreateFile
                (
                    FileName,
                    GENERIC_READ,
                    0,
                    0,
                    OPEN_EXISTING,
                    0,
                    0
                );

                if (handle != IntPtr.Zero)
                {
                    return true;
                }
                else
                {
                    return false;
                }
            }

            public unsafe int Read(byte[] buffer, int index, int count)
            {
                int n = 0;
                fixed (byte* p = buffer)
                {
                    if (!ReadFile(handle, p + index, count, &n, 0))
                    {
                        return 0;
                    }
                }
                return n;
            }

            public unsafe int Write(IntPtr handleFile, byte[] bufferData, int index, int length)
            {
                int n = 0;
                fixed (byte* w = bufferData)
                {
                    if (!WriteFile(handleFile, w + index, length, &n, 0))
                    {
                        return 0;
                    }
                }
                return n;
            }

            public bool Close()
            {
                return CloseHandle(handle);
            }

        }

        private void button2_Click(object sender, EventArgs e)
        {
            Close();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            textBox1.AppendText("Создание файла... \r\n");
            CreateFile(Convert.ToInt32(numericUpDown1.Value));
            if (checkBox1.Checked)
            {
                textBox1.AppendText("Затраченное время на первый способ: " + FileVariable() + " миллисекунд \r\n");
            }
            if (checkBox2.Checked)
            {
                textBox1.AppendText("Затраченное время на второй способ: " + WinAPIFunc() + " миллисекунд \r\n");
            }
            textBox1.AppendText("\r\n");
            progressBar1.Value = 0;
        }

        private void CreateFile(int lenght)
        {
            byte[] buffer = new byte[1024]; //1Kb buffer
            int i;
            progressBar1.Maximum = lenght * 1024 * 1024;
            using (FileStream fs = new FileStream(fileSrc, FileMode.Create, FileAccess.Write))
            {
                for (i = 1; i <= lenght * 1024 * 1024; i += buffer.Length)
                {
                    fs.Write(buffer, 0, buffer.Length);
                    progressBar1.Value = i;
                }
                fs.Close();
            }

        }

        private int FileVariable()
        {
            int start, finish, result;
            progressBar1.Value = 0;
            progressBar1.Maximum = 100;
            start = DateTime.Now.Millisecond;
            File.Copy(fileSrc, fileDest, true);
            finish = DateTime.Now.Millisecond;
            progressBar1.Value = 70;
            result = finish - start;
            progressBar1.Value = 100;
            return result;
        }

        private int WinAPIFunc()
        {
            int start, finish, result;
            Win32 api = new Win32();
            if (api.Open(fileSrc))
            {
                start = DateTime.Now.Millisecond;
                byte[] buffer = new byte[1024];
                IntPtr h = Win32.CreateFile(fileDest, Win32.GENERIC_WRITE, 0, 0, 2, 0, 0);
                Debug.WriteLine(h.ToString());
                int bytesRead;
                do
                {
                    bytesRead = api.Read(buffer, 0, buffer.Length);
                    if (bytesRead != 0)
                    {
                        int wr = api.Write(h, buffer, 0, bytesRead);
                    }
                }
                while (bytesRead > 0);
                api.Close();
                Win32.CloseHandle(h);
                finish = DateTime.Now.Millisecond;
                result = finish - start;
                return result;
            }
            return 0;
        }
    }
}