Tile クラスに固定長の変数を持ち、次のようなものを実装したいとします。
これは、ファイルにシリアル化されたコレクションからインデックスに基づいて値を取得できるコレクション クラス (People) の例です。
Person は People コレクションのベースとなるクラスです。
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace FileStreamDatabaseTest
{
class Program
{
static void Main(string[] args)
{
People.OpenCollection();
People.Test_WillOverwriteData();
People.CloseCollection();
Console.ReadLine();
}
}
public class Person
{
// define maxium variable sizes for serialisation
protected static int pMaxLength_FirstName = 64;
protected static int pMaxLength_Age = 10;
public static int MaxObjectSize
{
get
{
// return the sum of all the maxlegnth variables to define the entire object size for serialisation
return pMaxLength_FirstName + pMaxLength_Age;
}
}
// define each object that will be serialised as follows
protected string pFirstName;
public string Firstname
{
set
{
// ensure the new value is not over max variable size
if (value.Length > pMaxLength_FirstName)
throw new Exception("the length of the value is to long.");
pFirstName = value;
}
get
{
return pFirstName;
}
}
protected int pAge;
public int Age
{
get
{
return pAge;
}
set
{
pAge = value;
}
}
public byte[] Serialise()
{
// Output string builder
StringBuilder Output = new StringBuilder();
// Append firstname value
Output.Append(Firstname);
// Add extra spaces to end of string until max length is reached
if (Firstname.Length < pMaxLength_FirstName)
for (int i = Firstname.Length; i < pMaxLength_FirstName; i++)
Output.Append(" ");
// Append age value as string
Output.Append(Age.ToString());
// Add extra spaces to end of string until max length is reached
int AgeLength = Age.ToString().Length;
if (AgeLength < pMaxLength_Age)
for (int i = AgeLength; i < pMaxLength_Age; i++)
Output.Append(" ");
// Return the output string as bytes using ascii encoding
return System.Text.Encoding.ASCII.GetBytes(Output.ToString());
}
public void Deserialise(byte[] SerialisedData)
{
string Values = System.Text.Encoding.ASCII.GetString(SerialisedData);
pFirstName = Values.Substring(0, pMaxLength_FirstName).Trim();
pAge = int.Parse(Values.Substring(pMaxLength_FirstName, pMaxLength_Age).Trim());
}
}
public static class People
{
private static string tileDatasource = @"c:\test.dat";
private static System.IO.FileStream FileStream;
public static void OpenCollection()
{
FileStream = new System.IO.FileStream(tileDatasource, System.IO.FileMode.OpenOrCreate, System.IO.FileAccess.ReadWrite, System.IO.FileShare.None);
}
public static void CloseCollection()
{
FileStream.Close();
FileStream.Dispose();
FileStream = null;
}
public static void SaveCollection(Person[] People)
{
FileStream.SetLength(People.Length * Person.MaxObjectSize);
FileStream.Position = 0;
foreach (Person PersonToWrite in People)
{
// call serialise to get bytes
byte[] OutputBytes = PersonToWrite.Serialise();
// write the output buffer
// note: this will always be the same size as each variable should
// append spaces until its max size is reached
FileStream.Write(OutputBytes, 0, OutputBytes.Length);
}
}
public static Person GetValue(int Index)
{
// set the stream position to read the object by multiplying the requested index with the max object size
FileStream.Position = Index * Person.MaxObjectSize;
// read the data
byte[] InputBytes = new byte[Person.MaxObjectSize];
FileStream.Read(InputBytes, 0, Person.MaxObjectSize);
// deserialise
Person PersonToReturn = new Person();
PersonToReturn.Deserialise(InputBytes);
// retun the person
return PersonToReturn;
}
public static void Test_WillOverwriteData()
{
long StartTime;
long EndTime;
TimeSpan TimeTaken;
Console.WriteLine("-------------------------------------------------------------------");
Console.WriteLine("*** Creating 2,000,000 test people... ");
StartTime = DateTime.Now.Ticks;
Person[] People = new Person[2000000];
for (int i = 0; i < 2000000; i++)
{
People[i] = new Person();
People[i].Firstname = "TestName." + i;
People[i].Age = i;
}
EndTime = DateTime.Now.Ticks;
TimeTaken = new TimeSpan(EndTime - StartTime);
Console.WriteLine("-> Completed in " + TimeTaken.TotalSeconds + " seconds");
Console.WriteLine("-------------------------------------------------------------------");
Console.WriteLine("*** Serialising Collection to disk... ");
StartTime = DateTime.Now.Ticks;
SaveCollection(People);
EndTime = DateTime.Now.Ticks;
TimeTaken = new TimeSpan(EndTime - StartTime);
Console.WriteLine("-> Completed in " + TimeTaken.TotalSeconds + " seconds");
Console.WriteLine("-------------------------------------------------------------------");
Console.WriteLine("*** Redundancy Test... ");
StartTime = DateTime.Now.Ticks;
bool Parsed = true;
int FailedCount = 0;
for (int i = 0; i < 2000000; i++)
{
if (GetValue(i).Age != i)
{
Parsed = false;
FailedCount++;
}
}
EndTime = DateTime.Now.Ticks;
TimeTaken = new TimeSpan(EndTime - StartTime);
Console.WriteLine("-> " + (Parsed ? "PARSED" : "FAILED (" + FailedCount + " failed index's"));
Console.WriteLine("-> Completed in " + TimeTaken.TotalSeconds + " seconds");
Console.WriteLine("-------------------------------------------------------------------");
Console.WriteLine("*** Reading 10,000 index's at once... ");
StartTime = DateTime.Now.Ticks;
Person[] ChunkOfPeople = new Person[10000];
for (int i = 0; i < 10000; i++)
ChunkOfPeople[i] = GetValue(i);
EndTime = DateTime.Now.Ticks;
TimeTaken = new TimeSpan(EndTime - StartTime);
Console.WriteLine("-> Completed in " + TimeTaken.TotalSeconds + " seconds");
Console.WriteLine("-------------------------------------------------------------------");
Console.WriteLine("*** Reading 100,000 index's at once... ");
StartTime = DateTime.Now.Ticks;
ChunkOfPeople = new Person[100000];
for (int i = 0; i < 100000; i++)
ChunkOfPeople[i] = GetValue(i);
EndTime = DateTime.Now.Ticks;
TimeTaken = new TimeSpan(EndTime - StartTime);
Console.WriteLine("-> Completed in " + TimeTaken.TotalSeconds + " seconds");
Console.WriteLine("-------------------------------------------------------------------");
Console.WriteLine("*** Reading 1,000,000 index's at once... ");
StartTime = DateTime.Now.Ticks;
ChunkOfPeople = new Person[1000000];
for (int i = 0; i < 1000000; i++)
ChunkOfPeople[i] = GetValue(i);
EndTime = DateTime.Now.Ticks;
TimeTaken = new TimeSpan(EndTime - StartTime);
Console.WriteLine("-> Completed in " + TimeTaken.TotalSeconds + " seconds");
}
}
}