using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.IO; //need this for file io

//*********************************************************
// Binary data read/write:: The file will be created if
// it does not already exist. The file will be located in 
// your "project/bin/Release" folder
// Edwin Armstrong A.K.A. (efa)
//*********************************************************
//  Date      Comment                                  who
//=========   =======================================  ===
// 02/22/10   Working and tested version.              efa
// 02/23/10   Modified to encrypt/decrypt a file.      efa
//*********************************************************
namespace file_io_binary
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        //write data button (efa) 02/23/10
        private void button1_Click(object sender, EventArgs e)
        {
            FileStream fs = File.Create("test.dat");
            BinaryWriter bw = new BinaryWriter(fs);
           
            byte dataByte;
            string str;
            int len = 0; //length of string

            str = textBox1.Text;
            len = str.Length;

            foreach (char letter in str)
            {      
               dataByte = (byte)letter;
               dataByte = (byte)(dataByte + 7);// Not much of an encryption,
               bw.Write(dataByte);             // just add 7 to the byte data...              
            }

            bw.Close();
            fs.Close(); 
        }

        //read data button (efa) 02/23/10
        private void button2_Click(object sender, EventArgs e)
        {
            string fileName = "test.dat";
            char[] buffer = new char[1024];
            byte dataByte;
            int c = 0;

            if (File.Exists(fileName))
            {
                FileStream fs = File.OpenRead(fileName);
                BinaryReader br = new BinaryReader(fs);

                //get the files length
                System.IO.FileInfo fileInfo = new System.IO.FileInfo(@fileName);
                // write file length in bytes to textbox3
                this.textBox3.Text = fileInfo.Length.ToString();

                for (c = 0; c < fileInfo.Length; ++c)
                {
                   dataByte = br.ReadByte();
                   dataByte = (byte)(dataByte - 7);// Not much of an decryption,
                   buffer[c] = (char) dataByte;    // just subtract 7 from the byte...
                }

                string outStr = new string(buffer);
                textBox2.Text = outStr;

                br.Close();
                fs.Close();
            }
            else
            {
                MessageBox.Show("Can't find file [" + fileName + "]");
                return;
            }
        }

    }
}