Split and Assemble large file (around 2GB) in C# dot net Programming

Hi friends after a long time I’m back again. Now with a quite different coding flavor in different area. I will express about some operation with File. I will give some code to split and assemble large file. These codes can split up to 2 GB (approximately) file to any number of small file (minimum 1 MB) and also can assemble these small files to get the original file. Be sure that in assembling all small files need to keep in a folder otherwise it will fail to make original file and throw an error.

To do this in C# dot net , I’ve taken help of System.IO namespace and BinaryReader and BinaryWriter class. To learn about these classes please see msdn site. Here I’ve follow very simple algorithm.

For slice a file steps are:
(i) Open a large file in read mode by binary reader stream.
(ii) Execute step iii and step v, until file read reach at end of file.
(iii) Read from that stream and set these bytes in byte array
(iv) Make a new file name from original file name with slice number, for last file slice add ‘E’ after slice number.
(v) Save these bytes from array to a new file with ‘File’ class’s ‘WriteAllBytes’ method.
(vi) close the dot net binary stream.

Download source code from here:
http://alap.me/blog/All_Source_Codes.rar

These code as follows –

(i) BinaryReader br=new BinaryReader(File.Open(filename, FileMode.Open));

(ii) while (br.BaseStream.Length > sliceLen * counter)

(iii) br.BaseStream.Read(buffer, 0, sliceLen);
(iv) curFileName = filename + "." + counter.ToString();
curFileName = filename + "." + counter.ToString() + ".E";
(v) File.WriteAllBytes(curFileName, buffer);
(vi) br.Close();

For assemble these files need to follow these steps –

(i) Create a binary writer stream and open a binary file in append mode.
(ii) Execute from step iii to v
(iii) Generate file name in runtime depends on pervious file name.
(iv) Check for last file slice, last file slice name ends with last character ‘E’. If present file is the last slice then exit from that loop.
(v) Read all bytes from file and set in a byte array then write these byte data by binary writer.
(vi) Close the binary writer.

These code as follows-

(i) BinaryWriter bw = new BinaryWriter(File.Open(orgFile, FileMode.Append))
(ii) while(true)
(iii) nextFileName = orgFile + "." + counter.ToString();
(iv) if (File.Exists(nextFileName + ".E"))

(v) buffer = File.ReadAllBytes(nextFileName + ".E");
bw.Write(buffer);
(vii) bw.Close();

I’ve not covered everything in algorithm but I believe that you will understand these easily.

The complete codes are given below:

// File cutter assembler in microsoft c# dot net
//This code has written by Suman Biswas in 2008.
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.IO;

namespace FileCutter
{
//This class is used to call the actual file operation class.
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
this.Text = "File cutter & assembler (upto 1.96 GB) by Suman Biswas";
}
FileHandling obj = new FileHandling();
private void btnSelectFile_Click(object sender, EventArgs e)
{

obj.SplitUp(SelectFile(),int.Parse(textBox1.Text));


}

private void button1_Click(object sender, EventArgs e)
{
obj.MargeUp(SelectFile());
}
private string SelectFile()
{
OpenFileDialog fbd = new OpenFileDialog();
if (fbd.ShowDialog() != DialogResult.OK)
{
MessageBox.Show("No file selected");
return "";
}
else
return fbd.FileName;
}
}

//Main file operation is done here.
class FileHandling
{
int sliceLen = 1024 * 1024;
int counter = 0;

public void SplitUp(string filename,int fileSizeInMB)
{
if (fileSizeInMB < slicelen =" 1024" counter =" 0;" buffer="new" br="new" slicelen =" (int)br.BaseStream.Length;"> sliceLen * counter)
{
if (br.BaseStream.Length > sliceLen * (counter + 1))
{
br.BaseStream.Read(buffer, 0, sliceLen);
curFileName = filename + "." + counter.ToString();
}
else
{
int remainLen = (int)br.BaseStream.Length - sliceLen * counter;
buffer = new byte[remainLen];
br.BaseStream.Read(buffer, 0, remainLen);
curFileName = filename + "." + counter.ToString() + ".E";
}

if (File.Exists(curFileName))
File.Delete(curFileName);

File.WriteAllBytes(curFileName, buffer);
counter++;
}
br.Close();
MessageBox.Show("File spilitted successfully");
}

public void MargeUp(string firstFileName)
{
if (firstFileName.Length < 1)
return;

string endPart = firstFileName;
string orgFile = "";

orgFile = endPart.Substring(0, endPart.LastIndexOf("."));
endPart = endPart.Substring(endPart.LastIndexOf(".") + 1);

if (endPart == "E")//If only one slice is there
{
orgFile = orgFile.Substring(0, orgFile.LastIndexOf("."));
endPart = "0";
}

if (File.Exists(orgFile))
{
if (MessageBox.Show(orgFile + " already exists, do you want to delete it", "", MessageBoxButtons.YesNo) == DialogResult.Yes)
File.Delete(orgFile);
else
{
MessageBox.Show("File not assembled. Operation cancelled by user.");
return;
}
}

//Assembling starts from here
BinaryWriter bw = new BinaryWriter(File.Open(orgFile, FileMode.Append));
string nextFileName = "";
byte []buffer=new byte [bw.BaseStream.Length];


int counter=int.Parse(endPart);
while(true)
{
nextFileName = orgFile + "." + counter.ToString();
if (File.Exists(nextFileName + ".E"))
{
//Last slice
buffer = File.ReadAllBytes(nextFileName + ".E");
bw.Write(buffer);
break;
}
else
{
buffer = File.ReadAllBytes(nextFileName);
bw.Write(buffer);
}
counter++;
}
bw.Close();
MessageBox.Show("File assebled successfully");
}

}

}