zlib compressing byte array?

Question

I have this uncompressed byte array:

0E 7C BD 03 6E 65 67 6C 65 63 74 00 00 00 00 00 00 00 00 00 42 52 00 00 01 02 01
         


        

Answer 1

Quite simply what you got had a GZip header. What you want is the simpler Zlib header. ZLib has options for GZip header, Zlib header or no header. Typically the Zlib header is used unless the data is associated with a disk file (in which case GZip header is used.) Apparently, there is no way with .Net library to write a zlib header (even though this is by far the most common header used in file formats). Try http://dotnetzip.codeplex.com/.

You can quickly test all the different zlib options using HexEdit (Operations->Compression->Settings). See http://www.hexedit.com . It took me 10 minutes to check your data by simply pasting your compressed bytes into HexEdit and decompressing. Also tried compressing your orignal bytes with GZip and ZLib headers as a double-check. Note that you may have to fiddle with the settings to get exactly the bytes you were expecting.