Anybody out there who wants to program the write-support for the zziplib? Actually, I just do not have the time to do it and no real need to but I guess it would be nice for people as for example to spit out savegame files in zipformat. The actual programming path is almost obvious - start off with the zziplib as it is, and let it open an existing zip-file. This will parse the central directory into memory - including the file-offsets for each file. Then, truncate the zip-realfile to the place that the central-dir was found (identical with the end of the last file). If a datafile is opened for writing, either add a new entry or modify the start-offset of the existing entry to the end of the zip-realfile - the old data is simply junk. Then init zlib to do the deflation of the data and append it to the current zip-realfile. When the zipdir-handle is getting closed from write-mode, the zip's central-directory needs to be appended to the file on disk. This coincides with creating a new zip-file with an empty central-directory that can be spit out to disk. During development, do not care about creating temp-files to guard against corruption for partial writes - the usual application will use the zziplib to create zip savegames in one turn, no "update"-operation needs to be implemented like exists in the standalone zip command utilities.
See the notes in the first paragraphs of ZZIP Programmers Interface description. It would add some complexity for something I never needed so far. The question came up with using zziplib as the backend of a dynamic webserver to store the content in compressed form possibly through the incarnation of a php module - and some scripted functionality that walks all directories to index the files hosted. I'm not going to implement that myself but perhaps someone else wants to do it and send me patches for free.
A subproject that shows all the steps from a dat-tree to a dat-zip to an obfuscated-dat along with build-files and source-files for all helper tools needed to obfuscate and deobfuscate, plus a sample program to use the obfuscated dat-file and make some use of it. Along with some extra documentation about 20..40 hours. Don't underestimate the amount of work for it! (otherwise a great student project).
The infozip tools implement a full set of zip/unzip routines based on internal code to access the zip-format. The zziplib has its own set of zip-format routines. Still, it should be possible to write a frontend to the library that implements parts (if not all) of the options of the infozip zip/unzip tools. Even without write-support in zziplib it would be interesting to see an normal unzip-tool that does not use the magic-wrappers thereby only going off at plain zip-files. On the upside, such a tool would be smaller than the infozip tools since it can use the library routines that are shared with other tools as well. Again - don't underestimate the amount of work for it, I guess 40..80 hours as there is a lot of fine-tuning needed to match the infozip model.