format using deflateInit2(). You can also request that inflate decode
the gzip format using inflateInit2(). Read zlib.h for more details.
- Note that you cannot specify special gzip header contents (e.g. a file
- name or modification date), nor will inflate tell you what was in the
- gzip header. If you need to customize the header or see what's in it,
- you can use the raw deflate and inflate operations and the crc32()
- function and roll your own gzip encoding and decoding. Read the gzip
- RFC 1952 for details of the header and trailer format.
-
21. Is zlib thread-safe?
Yes. However any library routines that zlib uses and any application-
were downright silly. So now, we simply make sure that the code always
works.
-36. Will zlib read the (insert any ancient or arcane format here) compressed
+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.
-37. How can I encrypt/decrypt zip files with zlib?
+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/
-38. What's the difference between the "gzip" and "deflate" HTTP 1.1 encodings?
+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
Bottom line: use the gzip format for HTTP 1.1 encoding.
-39. Does zlib support the new "Deflate64" format introduced by PKWare?
+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.
-40. Can you please sign these lengthy legal documents and fax them back to us
+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.
ZLIB DATA COMPRESSION LIBRARY
-zlib 1.2.2 is a general purpose data compression library. All the code is
+zlib 1.2.3 is a general purpose data compression library. All the code is
thread safe. The data format used by the zlib library is described by RFCs
(Request for Comments) 1950 to 1952 in the files
http://www.ietf.org/rfc/rfc1950.txt (zlib format), rfc1951.txt (deflate format)
To compile all files and run the test program, follow the instructions given at
the top of Makefile. In short "make test; make install" should work for most
-machines. For Unix: "./configure; make test; make install" For MSDOS, use one
-of the special makefiles such as Makefile.msc. For VMS, use Make_vms.com or
-descrip.mms.
+machines. For Unix: "./configure; make test; make install". For MSDOS, use one
+of the special makefiles such as Makefile.msc. For VMS, use make_vms.com.
Questions about zlib should be sent to <zlib@gzip.org>, or to Gilles Vollant
<info@winimage.com> for the Windows DLL version. The zlib home page is
issue of Dr. Dobb's Journal; a copy of the article is available in
http://dogma.net/markn/articles/zlibtool/zlibtool.htm
-The changes made in version 1.2.2 are documented in the file ChangeLog.
+The changes made in version 1.2.3 are documented in the file ChangeLog.
Unsupported third party contributions are provided in directory "contrib".
/* inflate.h -- internal inflate state definition
- * Copyright (C) 1995-2003 Mark Adler
+ * Copyright (C) 1995-2004 Mark Adler
* For conditions of distribution and use, see copyright notice in zlib.h
*/
/* Possible inflate modes between inflate() calls */
typedef enum {
HEAD, /* i: waiting for magic header */
-#ifdef GUNZIP
FLAGS, /* i: waiting for method and flags (gzip) */
TIME, /* i: waiting for modification time (gzip) */
OS, /* i: waiting for extra flags and operating system (gzip) */
NAME, /* i: waiting for end of file name (gzip) */
COMMENT, /* i: waiting for end of comment (gzip) */
HCRC, /* i: waiting for header crc (gzip) */
-#endif
DICTID, /* i: waiting for dictionary check value */
DICT, /* waiting for inflateSetDictionary() call */
TYPE, /* i: waiting for type bits, including last-flag bit */
MATCH, /* o: waiting for output space to copy string */
LIT, /* o: waiting for output space to write literal */
CHECK, /* i: waiting for 32-bit check value */
-#ifdef GUNZIP
LENGTH, /* i: waiting for 32-bit length (gzip) */
-#endif
DONE, /* finished check, done -- remain here until reset */
BAD, /* got a data error -- remain here until reset */
MEM, /* got an inflate() memory error -- remain here until reset */
int wrap; /* bit 0 true for zlib, bit 1 true for gzip */
int havedict; /* true if dictionary provided */
int flags; /* gzip header method and flags (0 if zlib) */
+ unsigned dmax; /* zlib header max distance (INFLATE_STRICT) */
unsigned long check; /* protected copy of check value */
unsigned long total; /* protected copy of output count */
+ gz_headerp head; /* where to save gzip header information */
/* sliding window */
unsigned wbits; /* log base 2 of requested window size */
unsigned wsize; /* window size or zero if not using window */
projects / wxWidgets.git / commitdiff
