Ex.Streams - 05. Slicing File

namespace _05.Slicing_File
{
    using System.IO;
    using System;

    public class Program
    {
        public static void Main()
        {
            var source = Path.Combine(Environment.CurrentDirectory, "..\\..\\randomVideo.mp4");

            var destinationDirectory = Path.Combine(Environment.CurrentDirectory, "..\\..\\DestinationForSlices\\");

            var parts = 5;

            Slice(source, destinationDirectory, parts);
        }

        private static void Slice(string source, string destinationDirectory, int partsCount)
        {
            using (var fsReader = new FileStream(source, FileMode.Open, FileAccess.Read, FileShare.None))
            {
                var header = new byte[4096];

                var bufferSize =(int)Math.Ceiling((fsReader.Length - header.Length) / (double) partsCount );

                fsReader.Read(header, 0, header.Length);

                var buffer = new byte[bufferSize];

                for (int i = 1; i <= partsCount; i++)
                {
                    fsReader.Read(buffer, 0, buffer.Length);

                    var filePathInDestination = $"{destinationDirectory}Part{i}.mp4";


                    using (var fsWriter = new FileStream(filePathInDestination
                        , FileMode.Create))
                    {
                        fsWriter.Write(header, 0, header.Length);
                        fsWriter.Write(buffer, 0, buffer.Length);
                    }
                }
            }
        }
    }
}