Compression/Decompression string with C#

by

The code to compress/decompress a string

public static void CopyTo(Stream src, Stream dest) {
    byte[] bytes = new byte[4096];

    int cnt;

    while ((cnt = src.Read(bytes, 0, bytes.Length)) != 0) {
        dest.Write(bytes, 0, cnt);
    }
}

public static byte[] Zip(string str) {
    var bytes = Encoding.UTF8.GetBytes(str);

    using (var msi = new MemoryStream(bytes))
    using (var mso = new MemoryStream()) {
        using (var gs = new GZipStream(mso, CompressionMode.Compress)) {
            //msi.CopyTo(gs);
            CopyTo(msi, gs);
        }

        return mso.ToArray();
    }
}

public static string Unzip(byte[] bytes) {
    using (var msi = new MemoryStream(bytes))
    using (var mso = new MemoryStream()) {
        using (var gs = new GZipStream(msi, CompressionMode.Decompress)) {
            //gs.CopyTo(mso);
            CopyTo(gs, mso);
        }

        return Encoding.UTF8.GetString(mso.ToArray());
    }
}

static void Main(string[] args) {
    byte[] r1 = Zip("StringStringStringStringStringStringStringStringStringStringStringStringStringString");
    string r2 = Unzip(r1);
}

Remember that Zip returns a byte[], while Unzip returns a string. If you want a string from Zip you can Base64 encode it (for example by using Convert.ToBase64String(r1)) (the result of Zip is VERY binary! It isn’t something you can print to the screen or write directly in an XML)

The version suggested is for .NET 2.0, for .NET 4.0 use the MemoryStream.CopyTo.

IMPORTANT: The compressed contents cannot be written to the output stream until the GZipStream knows that it has all of the input (i.e., to effectively compress it needs all of the data). You need to make sure that you Dispose() of the GZipStream before inspecting the output stream (e.g., mso.ToArray()). This is done with the using() { } block above. Note that the GZipStream is the innermost block and the contents are accessed outside of it. The same goes for decompressing: Dispose() of the GZipStream before attempting to access the data.

More Related Contents:

  1. Is there an alternative to string.Replace that is case-insensitive?
  2. Really simple short string compression
  3. what’s the use of string.Clone()?
  4. Reversing the given string without using reverse function [closed]
  5. Why does Read interfere with ReadLine? [duplicate]
  6. Easiest way to read from and write to files
  7. How to detect Windows 64-bit platform with .NET?
  8. Easiest way to split a string on newlines in .NET?
  9. How do I use LINQ Contains(string[]) instead of Contains(string)
  10. Add spaces before Capital Letters
  11. How to read an entire file to a string using C#?
  12. Creating a comma separated list from IList or IEnumerable
  13. What does {0} mean when found in a string in C#?
  14. How to call a VBScript file in a C# application?
  15. How can I format a number into a string with leading zeros?
  16. Is string in array?
  17. Converting from hex to string
  18. Remove text in-between delimiters in a string (using a regex?)
  19. Encode a FileStream to base64 with c#
  20. How does StringBuilder work internally in C#?
  21. Display Float as String with at Least 1 Decimal Place
  22. Delete last char of string
  23. Why is \ character being doubled in my @ string?
  24. string.Join on a List or other type
  25. How to sort list of Ip Addresses using c#
  26. String comparison – strA.ToLower()==strB.ToLower() or strA.Equals(strB,StringComparisonType)?
  27. Regular expression to find and remove duplicate words
  28. Adding a newline into a string in C#
  29. Using StreamReader to check if a file contains a string
  30. How can I create all possible combinations for a set of words without repetition?

Leave a Comment