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diff --git a/source4/lib/zlib/FAQ b/source4/lib/zlib/FAQ deleted file mode 100644 index 441d910daa..0000000000 --- a/source4/lib/zlib/FAQ +++ /dev/null @@ -1,339 +0,0 @@ - - Frequently Asked Questions about zlib - - -If your question is not there, please check the zlib home page -http://www.zlib.org which may have more recent information. -The lastest zlib FAQ is at http://www.gzip.org/zlib/zlib_faq.html - - - 1. Is zlib Y2K-compliant? - - Yes. zlib doesn't handle dates. - - 2. Where can I get a Windows DLL version? - - The zlib sources can be compiled without change to produce a DLL. - See the file win32/DLL_FAQ.txt in the zlib distribution. - Pointers to the precompiled DLL are found in the zlib web site at - http://www.zlib.org. - - 3. Where can I get a Visual Basic interface to zlib? - - See - * http://www.dogma.net/markn/articles/zlibtool/zlibtool.htm - * contrib/visual-basic.txt in the zlib distribution - * win32/DLL_FAQ.txt in the zlib distribution - - 4. compress() returns Z_BUF_ERROR. - - Make sure that before the call of compress, the length of the compressed - buffer is equal to the total size of the compressed buffer and not - zero. For Visual Basic, check that this parameter is passed by reference - ("as any"), not by value ("as long"). - - 5. deflate() or inflate() returns Z_BUF_ERROR. - - Before making the call, make sure that avail_in and avail_out are not - zero. When setting the parameter flush equal to Z_FINISH, also make sure - that avail_out is big enough to allow processing all pending input. - Note that a Z_BUF_ERROR is not fatal--another call to deflate() or - inflate() can be made with more input or output space. A Z_BUF_ERROR - may in fact be unavoidable depending on how the functions are used, since - it is not possible to tell whether or not there is more output pending - when strm.avail_out returns with zero. - - 6. Where's the zlib documentation (man pages, etc.)? - - It's in zlib.h for the moment, and Francis S. Lin has converted it to a - web page zlib.html. Volunteers to transform this to Unix-style man pages, - please contact us (zlib@gzip.org). Examples of zlib usage are in the files - example.c and minigzip.c. - - 7. Why don't you use GNU autoconf or libtool or ...? - - Because we would like to keep zlib as a very small and simple - package. zlib is rather portable and doesn't need much configuration. - - 8. I found a bug in zlib. - - Most of the time, such problems are due to an incorrect usage of - zlib. Please try to reproduce the problem with a small program and send - the corresponding source to us at zlib@gzip.org . Do not send - multi-megabyte data files without prior agreement. - - 9. Why do I get "undefined reference to gzputc"? - - If "make test" produces something like - - example.o(.text+0x154): undefined reference to `gzputc' - - check that you don't have old files libz.* in /usr/lib, /usr/local/lib or - /usr/X11R6/lib. Remove any old versions, then do "make install". - -10. I need a Delphi interface to zlib. - - See the contrib/delphi directory in the zlib distribution. - -11. Can zlib handle .zip archives? - - Not by itself, no. See the directory contrib/minizip in the zlib - distribution. - -12. Can zlib handle .Z files? - - No, sorry. You have to spawn an uncompress or gunzip subprocess, or adapt - the code of uncompress on your own. - -13. How can I make a Unix shared library? - - make clean - ./configure -s - make - -14. How do I install a shared zlib library on Unix? - - After the above, then: - - make install - - However, many flavors of Unix come with a shared zlib already installed. - Before going to the trouble of compiling a shared version of zlib and - trying to install it, you may want to check if it's already there! If you - can #include <zlib.h>, it's there. The -lz option will probably link to it. - -15. I have a question about OttoPDF. - - We are not the authors of OttoPDF. The real author is on the OttoPDF web - site: Joel Hainley, jhainley@myndkryme.com. - -16. Can zlib decode Flate data in an Adobe PDF file? - - Yes. See http://www.fastio.com/ (ClibPDF), or http://www.pdflib.com/ . - To modify PDF forms, see http://sourceforge.net/projects/acroformtool/ . - -17. Why am I getting this "register_frame_info not found" error on Solaris? - - After installing zlib 1.1.4 on Solaris 2.6, running applications using zlib - generates an error such as: - - ld.so.1: rpm: fatal: relocation error: file /usr/local/lib/libz.so: - symbol __register_frame_info: referenced symbol not found - - The symbol __register_frame_info is not part of zlib, it is generated by - the C compiler (cc or gcc). You must recompile applications using zlib - which have this problem. This problem is specific to Solaris. See - http://www.sunfreeware.com for Solaris versions of zlib and applications - using zlib. - -18. Why does gzip give an error on a file I make with compress/deflate? - - The compress and deflate functions produce data in the zlib format, which - is different and incompatible with the gzip format. The gz* functions in - zlib on the other hand use the gzip format. Both the zlib and gzip - formats use the same compressed data format internally, but have different - headers and trailers around the compressed data. - -19. Ok, so why are there two different formats? - - The gzip format was designed to retain the directory information about - a single file, such as the name and last modification date. The zlib - format on the other hand was designed for in-memory and communication - channel applications, and has a much more compact header and trailer and - uses a faster integrity check than gzip. - -20. Well that's nice, but how do I make a gzip file in memory? - - You can request that deflate write the gzip format instead of the zlib - format using deflateInit2(). You can also request that inflate decode - the gzip format using inflateInit2(). Read zlib.h for more details. - -21. Is zlib thread-safe? - - Yes. However any library routines that zlib uses and any application- - provided memory allocation routines must also be thread-safe. zlib's gz* - functions use stdio library routines, and most of zlib's functions use the - library memory allocation routines by default. zlib's Init functions allow - for the application to provide custom memory allocation routines. - - Of course, you should only operate on any given zlib or gzip stream from a - single thread at a time. - -22. Can I use zlib in my commercial application? - - Yes. Please read the license in zlib.h. - -23. Is zlib under the GNU license? - - No. Please read the license in zlib.h. - -24. The license says that altered source versions must be "plainly marked". So - what exactly do I need to do to meet that requirement? - - You need to change the ZLIB_VERSION and ZLIB_VERNUM #defines in zlib.h. In - particular, the final version number needs to be changed to "f", and an - identification string should be appended to ZLIB_VERSION. Version numbers - x.x.x.f are reserved for modifications to zlib by others than the zlib - maintainers. For example, if the version of the base zlib you are altering - is "1.2.3.4", then in zlib.h you should change ZLIB_VERNUM to 0x123f, and - ZLIB_VERSION to something like "1.2.3.f-zachary-mods-v3". You can also - update the version strings in deflate.c and inftrees.c. - - For altered source distributions, you should also note the origin and - nature of the changes in zlib.h, as well as in ChangeLog and README, along - with the dates of the alterations. The origin should include at least your - name (or your company's name), and an email address to contact for help or - issues with the library. - - Note that distributing a compiled zlib library along with zlib.h and - zconf.h is also a source distribution, and so you should change - ZLIB_VERSION and ZLIB_VERNUM and note the origin and nature of the changes - in zlib.h as you would for a full source distribution. - -25. Will zlib work on a big-endian or little-endian architecture, and can I - exchange compressed data between them? - - Yes and yes. - -26. Will zlib work on a 64-bit machine? - - It should. It has been tested on 64-bit machines, and has no dependence - on any data types being limited to 32-bits in length. If you have any - difficulties, please provide a complete problem report to zlib@gzip.org - -27. Will zlib decompress data from the PKWare Data Compression Library? - - No. The PKWare DCL uses a completely different compressed data format - than does PKZIP and zlib. However, you can look in zlib's contrib/blast - directory for a possible solution to your problem. - -28. Can I access data randomly in a compressed stream? - - No, not without some preparation. If when compressing you periodically - use Z_FULL_FLUSH, carefully write all the pending data at those points, - and keep an index of those locations, then you can start decompression - at those points. You have to be careful to not use Z_FULL_FLUSH too - often, since it can significantly degrade compression. - -29. Does zlib work on MVS, OS/390, CICS, etc.? - - We don't know for sure. We have heard occasional reports of success on - these systems. If you do use it on one of these, please provide us with - a report, instructions, and patches that we can reference when we get - these questions. Thanks. - -30. Is there some simpler, easier to read version of inflate I can look at - to understand the deflate format? - - First off, you should read RFC 1951. Second, yes. Look in zlib's - contrib/puff directory. - -31. Does zlib infringe on any patents? - - As far as we know, no. In fact, that was originally the whole point behind - zlib. Look here for some more information: - - http://www.gzip.org/#faq11 - -32. Can zlib work with greater than 4 GB of data? - - Yes. inflate() and deflate() will process any amount of data correctly. - Each call of inflate() or deflate() is limited to input and output chunks - of the maximum value that can be stored in the compiler's "unsigned int" - type, but there is no limit to the number of chunks. Note however that the - strm.total_in and strm_total_out counters may be limited to 4 GB. These - counters are provided as a convenience and are not used internally by - inflate() or deflate(). The application can easily set up its own counters - updated after each call of inflate() or deflate() to count beyond 4 GB. - compress() and uncompress() may be limited to 4 GB, since they operate in a - single call. gzseek() and gztell() may be limited to 4 GB depending on how - zlib is compiled. See the zlibCompileFlags() function in zlib.h. - - The word "may" appears several times above since there is a 4 GB limit - only if the compiler's "long" type is 32 bits. If the compiler's "long" - type is 64 bits, then the limit is 16 exabytes. - -33. Does zlib have any security vulnerabilities? - - The only one that we are aware of is potentially in gzprintf(). If zlib - is compiled to use sprintf() or vsprintf(), then there is no protection - against a buffer overflow of a 4K string space, other than the caller of - gzprintf() assuring that the output will not exceed 4K. On the other - hand, if zlib is compiled to use snprintf() or vsnprintf(), which should - normally be the case, then there is no vulnerability. The ./configure - script will display warnings if an insecure variation of sprintf() will - be used by gzprintf(). Also the zlibCompileFlags() function will return - information on what variant of sprintf() is used by gzprintf(). - - If you don't have snprintf() or vsnprintf() and would like one, you can - find a portable implementation here: - - http://www.ijs.si/software/snprintf/ - - Note that you should be using the most recent version of zlib. Versions - 1.1.3 and before were subject to a double-free vulnerability. - -34. Is there a Java version of zlib? - - Probably what you want is to use zlib in Java. zlib is already included - as part of the Java SDK in the java.util.zip package. If you really want - a version of zlib written in the Java language, look on the zlib home - page for links: http://www.zlib.org/ - -35. I get this or that compiler or source-code scanner warning when I crank it - up to maximally-pedantic. Can't you guys write proper code? - - Many years ago, we gave up attempting to avoid warnings on every compiler - in the universe. It just got to be a waste of time, and some compilers - were downright silly. So now, we simply make sure that the code always - works. - -36. Valgrind (or some similar memory access checker) says that deflate is - performing a conditional jump that depends on an uninitialized value. - Isn't that a bug? - - No. That is intentional for performance reasons, and the output of - deflate is not affected. This only started showing up recently since - zlib 1.2.x uses malloc() by default for allocations, whereas earlier - versions used calloc(), which zeros out the allocated memory. - -37. Will zlib read the (insert any ancient or arcane format here) compressed - data format? - - Probably not. Look in the comp.compression FAQ for pointers to various - formats and associated software. - -38. How can I encrypt/decrypt zip files with zlib? - - zlib doesn't support encryption. The original PKZIP encryption is very weak - and can be broken with freely available programs. To get strong encryption, - use GnuPG, http://www.gnupg.org/ , which already includes zlib compression. - For PKZIP compatible "encryption", look at http://www.info-zip.org/ - -39. What's the difference between the "gzip" and "deflate" HTTP 1.1 encodings? - - "gzip" is the gzip format, and "deflate" is the zlib format. They should - probably have called the second one "zlib" instead to avoid confusion - with the raw deflate compressed data format. While the HTTP 1.1 RFC 2616 - correctly points to the zlib specification in RFC 1950 for the "deflate" - transfer encoding, there have been reports of servers and browsers that - incorrectly produce or expect raw deflate data per the deflate - specficiation in RFC 1951, most notably Microsoft. So even though the - "deflate" transfer encoding using the zlib format would be the more - efficient approach (and in fact exactly what the zlib format was designed - for), using the "gzip" transfer encoding is probably more reliable due to - an unfortunate choice of name on the part of the HTTP 1.1 authors. - - Bottom line: use the gzip format for HTTP 1.1 encoding. - -40. Does zlib support the new "Deflate64" format introduced by PKWare? - - No. PKWare has apparently decided to keep that format proprietary, since - they have not documented it as they have previous compression formats. - In any case, the compression improvements are so modest compared to other - more modern approaches, that it's not worth the effort to implement. - -41. Can you please sign these lengthy legal documents and fax them back to us - so that we can use your software in our product? - - No. Go away. Shoo. |