files_performance_test.cs

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

namespace FilePerformanceTest
{
	class Program
	{
		private static readonly int FILES_COUNT = 10000;
		private static readonly string Dir = "TestData";

		static void MakeManyFiles()
		{
			var random = new Random();

			if (!Directory.Exists(Dir))
				Directory.CreateDirectory(Dir);

			for (int i = 0; i < FILES_COUNT; ++i)
			{
				string filename = $"./{Dir}/{i:0000}.bytes";
				if (File.Exists(filename))
					continue;

				StringBuilder builder = new StringBuilder();

				var randomExiter = random.Next(0, 512);
				while (builder.Length < 128 || random.Next(0, 512) != randomExiter)
					builder.Append((char) ('A' + random.Next(24)));

				var contents = builder.ToString();
				File.WriteAllText(filename, contents);
			}
		}

		static void MakeOneFileFromManyFiles()
		{
			if (File.Exists("Test.bytes"))
				return;

			StringBuilder builder = new StringBuilder();
			for (int i = 0; i < FILES_COUNT; ++i)
			{
				string filename = $"./{Dir}/{i:0000}.bytes";
				string contents = File.ReadAllText(filename);
				builder.AppendLine(filename);
				builder.AppendLine(contents);
			}

			File.WriteAllText("Test.bytes", builder.ToString());
		}

		static void ParseFilesWithFirstLoads()
		{
			var files = new Dictionary<string, string>();
			for (int i = 0; i < FILES_COUNT; ++i)
			{
				string filename = $"./{Dir}/{i:0000}.bytes";
				string contents = File.ReadAllText(filename);
				files.Add(filename, contents);
			}

			for (int i = 0; i < FILES_COUNT; ++i)
			{
				string filename = $"./{Dir}/{i:0000}.bytes";
				foreach (var ch in files[filename])
					;
			}
		}

		static void ParseFilesPerLoop()
		{
			for (int i = 0; i < FILES_COUNT; ++i)
			{
				string filename = $"./{Dir}/{i:0000}.bytes";
				string contents = File.ReadAllText (filename);
				foreach (var ch in contents)
					;
			}
		}

		static void ParseFilesFromOneFile()
		{
			var files = new Dictionary<string, string> ();
			var lines = File.ReadAllLines("Test.bytes");
			for (int i = 0; i < lines.Length; i += 2)
				files.Add(lines[i], lines[i + 1]);

			for (int i = 0; i < FILES_COUNT; ++i)
			{
				string filename = $"./{Dir}/{i:0000}.bytes";
				foreach (var ch in files [filename])
					;
			}
		}

		static void Main (string [] args)
		{
			Console.WriteLine("[Files Initialize...]");
			MakeManyFiles();
			MakeOneFileFromManyFiles();

			Stopwatch stopwatch = new Stopwatch();

			stopwatch.Reset();
			stopwatch.Start();

			ParseFilesWithFirstLoads ();

			stopwatch.Stop();
			Console.WriteLine("Parse files with first loads: {0}", stopwatch.Elapsed);

			stopwatch.Reset ();
			stopwatch.Start ();

			ParseFilesPerLoop ();

			stopwatch.Stop ();
			Console.WriteLine ("Parse files per loop: {0}", stopwatch.Elapsed);

			stopwatch.Reset ();
			stopwatch.Start ();

			ParseFilesFromOneFile();

			stopwatch.Stop ();
			Console.WriteLine ("Parse files from one file: {0}", stopwatch.Elapsed);
		}
	}
}

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