[ Trimmed Cc list; added original zlib authors. ]
On Tuesday 29 May 2007 09:33:51 Michael-Luke Jones wrote: > On 29 May 2007, at 12:27, Satyam Sharma wrote: > > Right, actually, zlib could be switched over to [using a common > > directory]. > > Because zlib_deflate/ and zlib_inflate/ too share a private header > > zutil.h which has unfortunately been stuck into include/linux/ with > > a big > > /* WARNING: this file should *not* be used by applications. */ > > comment ... > > Well, unfortunately zutil.h is currently being used in-kernel by fs/ > jffs2/compr_zlib.c despite the "WARNING: this file should *not* be > used by applications" notice.
Hmmm, either jffs2 thinks the zlib interfaces exposed through include/linux/zlib.h are insufficient, or it isn't using zlib properly (or at least the way it was supposed to be used :-) Looking at fs/jffs2/compr_zlib.c, however, it just seems to be an optimization -- skipping some checksum calculation if some flag (PRESET_DICT) is absent from the input stream about to be decompressed ... This /looks/ like an optimization that might make sense for other users of zlib too, in which case that entire check and skip-the-checksum thing could actually be put into zlib proper. (?)
> So moving this header to a truly private location isn't possible > right now, unfortunately, > > Michael-Luke Jones > [added David Whitehouse to cc]
On 5/29/07, Daniel Hazelton <[EMAIL PROTECTED]> wrote:
I've looked at that code and it seems to need that file for one constant. Perhaps it'd be better for jffs2/compr_zlib.c to define that constant itself (or use it as a "Magic Number") rather than include the zlib private header. Another possibility would be to move that constant out of zutil.h and into zconf.h or zlih.b - doing any of those would allow the zlib private header to be moved such that zlib could be changed to use a common directory *and* have said private header in that directory.
Moving PRESET_DICT to zlib.h robs lib/zlib_deflate/deflate.c from being able to resolve that macro. FWIW, a dirty hack could be to simply duplicate it in zlib.h. But then, implementation and interface are decoupled for good reasons ... Satyam - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
