read GeoIPFile and GeoIP6File straight out of ZIP (.apk, .jar, .zip, .ipa)
Right now, the geoip and geoip6 files are packed into the APK, which is basically a ZIP/JAR file. Then when Orbot/TorBrowser/etc starts, it unzips those files to a local folder. Since those files are read only, they could be read directly out of the zip file. This would mean faster startup times and less disk space in use. Right now, there is a full ZIP read, then a full write, then a full read from disk.
I believe that tor is already linked against zlib, so the functions are there. In any case, zlib is one of the few libs that are provided by the NDK.
Android already does things like this. For example, PNG files are stored uncompressed in the APK. The whole ZIP file is byte aligned for each PNG reading. Then the APK maintains a list of pointers to the byte position in the APK file a PNG file can be read from.