如何进一步优化此代码和程序.我该怎么办?

问题描述

资源使用率几乎很好(10-20％CPU，RAM从8Mb开始并增长)，文件比较器是正常的，但是在7000+文件上程序运行缓慢.大约20-30分钟.如何优化?也许我不应该在函数中使用递归方法?也许结构没有优化?请帮忙.

The recource using is almost good(10-20% CPU, RAM starts from 8Mb and grows), file comparer is normal, but program is slow on 7000+ files. About 20-30 minutes. How optimize? Maybe i shouldn''t use recursive method in functions? Maybe the structure is not optimized? Please, help.

using System;
using System.Collections.Generic;
using System.IO;
using System.Diagnostics;

namespace ConsoleApplication3
{
    class Comparer
    {
        static void Main(string[] args)
        {
            Stopwatch s1 = new Stopwatch();
            s1.Start();
            switch (args.Length)
            {
                case 1:
                    {
                        CompareFilesRec(LookIn(args[0]));
                        s1.Stop();
                        break;
                    }
                default:
                    {
                        Console.WriteLine("Type only one argument.");
                        break;
                    }

            }
            
            Console.WriteLine("{0} ms", s1.ElapsedMilliseconds);
        }

        static bool CheckFile(string file)
        {
            FileInfo someFileInfo = new FileInfo(file);//берем інфу про файл в змінну someFileInfo
            if (someFileInfo.Length >= 2147483648 || someFileInfo.Length < 1)//перевірка
                return false;
            else return true;
        }
        static bool CheckDirEmpty(string dir)
        {
            DirectoryInfo someDir = new DirectoryInfo(dir);
            if (someDir.GetFiles().Length > 0)
                return false;
            else return true;
        }

        static List<string> LookIn(string path)
        {
            Stopwatch s1 = new Stopwatch();
            s1.Start();
            /*Ініціалізую і об*являю два списки:для файлів і папок*/
            List<string> files = new List<string>();
            List<string> dirs = new List<string>();

            /*Шукаєм всі доступні файли*/
            try
            {
                /*Добавляю знайдені папки і файли в список*/
                files.AddRange(Directory.GetFiles(path));
                dirs.AddRange(Directory.GetDirectories(path));    
            }
            catch (UnauthorizedAccessException) { }
            catch (DirectoryNotFoundException) { }
            catch (ArgumentOutOfRangeException) { }
            catch (IOException) { }

            for (int i = files.Count - 1; i >= 0; i--)
            {
                if (!CheckFile(files[i]))
                    files.RemoveAt(i);
            }
            for (int k = dirs.Count - 1; k >= 0; k--)
            {
                if(CheckDirEmpty(dirs[k]))
                    dirs.RemoveAt(k);
            }
            
            /*"Заглядаєм" за файлами в кожну директорію...*/
            foreach (string dir in dirs)
            {
                files.AddRange(LookIn(dir));//...і додаєм до списку
            }
            s1.Stop();
            Console.WriteLine("LookIN  = {0} ms", s1.ElapsedMilliseconds);
            return files;//повертаєм повний список знайдених файлів
        }

        static void CompareFilesRec(List<string> array)
        {
            Stopwatch s1 = new Stopwatch();
            s1.Start();
            List<KeyValuePair<long, string>> yeah = new List<KeyValuePair<long, string>>();
            List<string> Trash = new List<string>();
            List<string> outp = new List<string>();

            for (int j = array.Count-1; j >= 0; j--)
            {
                FileInfo fii = new FileInfo(array[j]);
                yeah.Add(new KeyValuePair<long, string>(fii.Length, array[j]));
            }
            array.Clear();

            foreach (var el in yeah)
            {
                if (!array.Contains(el.Value) && !Trash.Contains(el.Value))
                {
                    foreach (var ele in yeah)
                    {
                        if (el.Key == ele.Key && !array.Contains(ele.Value))
                        {
                            array.Add(ele.Value);
                        }
                        else
                        {
                            if (!Trash.Contains(ele.Value))
                            {
                                Trash.Add(ele.Value);
                            }
                        }
                    }
                }
            }
            yeah.Clear();
            /*TODO*/
            //byte crc = Crc8.ComputeChecksum(1, 2);
            int Arr = ComputeByteChecksum(array[0]);
            foreach (string f in array)
            {
                int File = ComputeByteChecksum(f);
                if (f != array[0] && Arr == File)
                    outp.Add(f);
                if (Arr != File)
                    if (!Trash.Contains(f))
                         Trash.Add(f);
            }
            outp.Add(array[0]);
            array.Clear();
            /*TODO end*/
            if (outp.Count > 1)
            {
                foreach (string fi in outp)
                {
                    Console.WriteLine(fi);
                }
                outp.Clear();
                Console.WriteLine();
            }
            
            if (Trash.Count > 1)
            {
                CompareFilesRec(Trash);
            }
            Trash.Clear();
            s1.Stop();
            Console.WriteLine("Comparing = {0} ms", s1.ElapsedMilliseconds);
        }
        static int ComputeByteChecksum(string path)
        {
            using (var reader = new BinaryReader(File.OpenRead(path)))
            {
                byte b1 = reader.ReadByte();
                reader.BaseStream.Position = reader.BaseStream.Position = reader.BaseStream.Length >> 1;
                byte b2 = reader.ReadByte();
                reader.BaseStream.Position = reader.BaseStream.Length - 1;
                byte b3 = reader.ReadByte();
                reader.Close();
                byte crc = Crc8.ComputeChecksum(1, 2);
                return Crc8.ComputeChecksum(b1, crc) + Crc8.ComputeChecksum(b2, crc) + Crc8.ComputeChecksum(b3, crc); 
            }
        }
    }
    public static class Crc8
    {
        static byte[] table = new byte[256];

        const byte poly = 0xd5;

        public static byte ComputeChecksum(params byte[] bytes)
        {
            byte crc = 0;
            if (bytes != null && bytes.Length > 0)
            {
                foreach (byte b in bytes)
                {
                    crc = table[crc ^ b];
                }
            }
            return crc;
        }

        static Crc8()
        {
            for (int i = 0; i < 256; ++i)
            {
                int temp = i;
                for (int j = 0; j < 8; ++j)
                {
                    if ((temp & 0x80) != 0)
                    {
                        temp = (temp << 1) ^ poly;
                    }
                    else
                    {
                        temp <<= 1;
                    }
                }
                table[i] = (byte)temp;
            }
        }
    }
}

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