Question Compressed String Length is high

christopher3683

New member
Joined
Aug 13, 2013
Messages
4
Programming Experience
5-10
Hi,

i have a string and i encrypt it and than Compressed that string.

Result is Length of the Compressed string is high.

I'm using the below code snippet

C#:
public static string Compress(string text)        {
            byte[] buffer = Encoding.UTF8.GetBytes(text);
            MemoryStream ms = new MemoryStream();
            using (GZipStream zip = new GZipStream(ms, CompressionMode.Compress, true))
            {
                zip.Write(buffer, 0, buffer.Length);
            }


            ms.Position = 0;
            MemoryStream outStream = new MemoryStream();


            byte[] compressed = new byte[ms.Length];
            ms.Read(compressed, 0, compressed.Length);


            byte[] gzBuffer = new byte[compressed.Length + 4];
            System.Buffer.BlockCopy(compressed, 0, gzBuffer, 4, compressed.Length);
            System.Buffer.BlockCopy(BitConverter.GetBytes(buffer.Length), 0, gzBuffer, 0, 4);
            return Convert.ToBase64String(gzBuffer);
        }


        public static string Decompress(string compressedText)
        {
            byte[] gzBuffer = Convert.FromBase64String(compressedText);
            using (MemoryStream ms = new MemoryStream())
            {
                int msgLength = BitConverter.ToInt32(gzBuffer, 0);
                ms.Write(gzBuffer, 4, gzBuffer.Length-4);


                byte[] buffer = new byte[msgLength];


                ms.Position = 0;


                using (GZipStream zip = new GZipStream(ms, CompressionMode.Decompress))
                {
                    zip.Read(buffer, 0, buffer.Length);
                }


                return Encoding.UTF8.GetString(buffer);
            }
        }

Please help me to resolve this problem
 
There is overhead with zip compression, if you for example compress a single Char you will get 125 bytes. You will start to see compression take effect with input strings of a few hundred chars.

Base64 encoding will also expand the length of input bytes with about 3 to 4 ratio.
 
Back
Top Bottom