A Simple String Compression Algorithm

Data compression is always useful for encoding information using fewer bits than the original representation it would use. There are many applications where the size of information would be critical. In data communication, the size of data can affect the cost too.

Form Code-Behind:

public byte[] ret;
SixBitEnDec obj = new SixBitEnDec();

private void Form1_Load(object sender, EventArgs e)
{
btnDecrypt.Enabled = false;
}

private void btnEncrypt_Click_1(object sender, EventArgs e)
{
ret = obj.encode(txtInput.Text, Convert.ToInt32(txtbit.Text));
     btnDecrypt.Enabled = true;
}

private void btnDecrypt_Click(object sender, EventArgs e)
{
txtResult.Text = obj.decode(ret, Convert.ToInt32(txtbit.Text));
}

Class File:

public class SixBitEnDec
    {
        static public int SIX_BIT = 6;
        static public int FIVE_BIT = 5;

        public SixBitEnDec() {

        }

        public byte[] encode(String txt, int bit)
        {
            int length = txt.Length;
            float tmpRet1 = 0, tmpRet2 = 0;

            if (bit == 6)
            {
                tmpRet1 = 3.0f;
                tmpRet2 = 4.0f;
            }
            else if (bit == 5)
            {
                tmpRet1 = 5.0f;
                tmpRet2 = 8.0f;
            }


            byte[] encoded = new byte[(int)(tmpRet1 * Math.Ceiling(length / tmpRet2))];
            char[] str = new char[length];

            int startIndex = 0;
            char[] chars = txt
                  .Where((c, i) => i >= startIndex && i < startIndex + length).ToArray();

            String temp;
            String strBinary = string.Empty;

            for (int i = 0; i < length; i++)
            {
                temp = Convert.ToString((toValue(chars[i])), 2);
                while (temp.Length % bit != 0)
                {
                    temp = "0" + temp;
                }
                strBinary = strBinary + temp;
            }

            while (strBinary.Length % 8 != 0)
            {
                strBinary = strBinary + "0";
            }

            Int32 tempInt = 0;
            for (int i = 0; i < strBinary.Length; i = i + 8)
            {
                tempInt = Convert.ToInt32(strBinary.Substring(i, 8), 2);
                encoded[i / 8] = Convert.ToByte(tempInt);
            }
            return encoded;
        }

        public String decode(byte[] encoded, int bit)
        {
            String strTemp = string.Empty;
            String strBinary = string.Empty;
            String strText = string.Empty;
            Int32 tempInt = 0;
            Int32 intTemp = 0;

            for (int i = 0; i < encoded.Length; i++)
            {
                if (encoded[i] < 0)
                {
                    intTemp = (int)encoded[i] + 256;
                }
                else
                    intTemp = (int)encoded[i];

                strTemp = Convert.ToString(intTemp, 2);

                while (strTemp.Length % 8 != 0)
                {
                    strTemp = "0" + strTemp;
                }
                strBinary = strBinary + strTemp;
            }
            for (int i = 0; i < strBinary.Length; i = i + bit)
            {
                tempInt = Convert.ToInt32(strBinary.Substring(i, bit), 2);
                strText = strText + toChar(Convert.ToInt32(tempInt));
            }
            return strText;
        }

        int toValue(char ch)
        {
            int chaVal = 0;
            switch (ch)
            {
                case ' ': chaVal = 0; break;
                case 'a': chaVal = 1; break;
                case 'b': chaVal = 2; break;
                case 'c': chaVal = 3; break;
                case 'd': chaVal = 4; break;
                case 'e': chaVal = 5; break;
                case 'f': chaVal = 6; break;
                case 'g': chaVal = 7; break;
                case 'h': chaVal = 8; break;
                case 'i': chaVal = 9; break;
                case 'j': chaVal = 10; break;
                case 'k': chaVal = 11; break;
                case 'l': chaVal = 12; break;
                case 'm': chaVal = 13; break;
                case 'n': chaVal = 14; break;
                case 'o': chaVal = 15; break;
                case 'p': chaVal = 16; break;
                case 'q': chaVal = 17; break;
                case 'r': chaVal = 18; break;
                case 's': chaVal = 19; break;
                case 't': chaVal = 20; break;
                case 'u': chaVal = 21; break;
                case 'v': chaVal = 22; break;
                case 'w': chaVal = 23; break;
                case 'x': chaVal = 24; break;
                case 'y': chaVal = 25; break;
                case 'z': chaVal = 26; break;
                case '.': chaVal = 27; break;
                case '*': chaVal = 28; break;
                case ',': chaVal = 29; break;
                case '\'': chaVal = 30; break;
                case '2': chaVal = 31; break;
                case 'A': chaVal = 32; break;
                case 'B': chaVal = 33; break;
                case 'C': chaVal = 34; break;
                case 'D': chaVal = 35; break;
                case 'E': chaVal = 36; break;
                case 'F': chaVal = 37; break;
                case 'G': chaVal = 38; break;
                case 'H': chaVal = 39; break;
                case 'I': chaVal = 40; break;
                case 'J': chaVal = 41; break;
                case 'K': chaVal = 42; break;
                case 'L': chaVal = 43; break;
                case 'M': chaVal = 44; break;
                case 'N': chaVal = 45; break;
                case 'O': chaVal = 46; break;
                case 'P': chaVal = 47; break;
                case 'Q': chaVal = 48; break;
                case 'R': chaVal = 49; break;
                case 'S': chaVal = 50; break;
                case 'T': chaVal = 51; break;
                case 'U': chaVal = 52; break;
                case 'V': chaVal = 53; break;
                case 'W': chaVal = 54; break;
                case '0': chaVal = 55; break;
                case '1': chaVal = 56; break;
                case '3': chaVal = 57; break;
                case '4': chaVal = 58; break;
                case '5': chaVal = 59; break;
                case '6': chaVal = 60; break;
                case '7': chaVal = 61; break;
                case '8': chaVal = 62; break;
                case '9': chaVal = 63; break;
                default: chaVal = 0; break;

            }
            return chaVal;
        }

        char toChar(int val)
        {
            char ch = ' ';
            switch (val)
            {
                case 0: ch = ' '; break;
                case 1: ch = 'a'; break;
                case 2: ch = 'b'; break;
                case 3: ch = 'c'; break;
                case 4: ch = 'd'; break;
                case 5: ch = 'e'; break;
                case 6: ch = 'f'; break;
                case 7: ch = 'g'; break;
                case 8: ch = 'h'; break;
                case 9: ch = 'i'; break;
                case 10: ch = 'j'; break;
                case 11: ch = 'k'; break;
                case 12: ch = 'l'; break;
                case 13: ch = 'm'; break;
                case 14: ch = 'n'; break;
                case 15: ch = 'o'; break;
                case 16: ch = 'p'; break;
                case 17: ch = 'q'; break;
                case 18: ch = 'r'; break;
                case 19: ch = 's'; break;
                case 20: ch = 't'; break;
                case 21: ch = 'u'; break;
                case 22: ch = 'v'; break;
                case 23: ch = 'w'; break;
                case 24: ch = 'x'; break;
                case 25: ch = 'y'; break;
                case 26: ch = 'z'; break;
                case 27: ch = '.'; break;
                case 28: ch = '*'; break;
                case 29: ch = ','; break;
                case 30: ch = '\''; break;
                case 31: ch = '2'; break;
                case 32: ch = 'A'; break;
                case 33: ch = 'B'; break;
                case 34: ch = 'C'; break;
                case 35: ch = 'D'; break;
                case 36: ch = 'E'; break;
                case 37: ch = 'F'; break;
                case 38: ch = 'G'; break;
                case 39: ch = 'H'; break;
                case 40: ch = 'I'; break;
                case 41: ch = 'J'; break;
                case 42: ch = 'K'; break;
                case 43: ch = 'L'; break;
                case 44: ch = 'M'; break;
                case 45: ch = 'N'; break;
                case 46: ch = 'O'; break;
                case 47: ch = 'P'; break;
                case 48: ch = 'Q'; break;
                case 49: ch = 'R'; break;
                case 50: ch = 'S'; break;
                case 51: ch = 'T'; break;
                case 52: ch = 'U'; break;
                case 53: ch = 'V'; break;
                case 54: ch = 'W'; break;
                case 55: ch = '0'; break;
                case 56: ch = '1'; break;
                case 57: ch = '3'; break;
                case 58: ch = '4'; break;
                case 59: ch = '5'; break;
                case 60: ch = '6'; break;
                case 61: ch = '7'; break;
                case 62: ch = '8'; break;
                case 63: ch = '9'; break;
                default: ch = ' '; break;
            }
            return ch;
        }
    }

Note:
Above code works fine for 6 bit encryption and decryption. Shortly i'll upload the code for 5 bit also.

For Referrences:
 http://www.codeproject.com/Articles/223610/A-Simple-String-Compression-Algorithm