Leopold Toetsch <[EMAIL PROTECTED]> writes: > Juergen Boemmels <[EMAIL PROTECTED]> wrote: > > Hi, > > > the latest changes of HASH in src/hash.c makes t/src/hash.t fail > > badly. > > Oops, sorry (but at least it isn't the only broken test currently :)
I committed a partial fix. Now the tests are at least compiling. > > But I still have one problem: hash_put and hash_get are not > > symmetric. hash_put puts a void *value, but hash_get returns a > > HASHBUCKET. This looks wrong to me. > > When returning the value directly, we couldn't have NULL value's - or > better NULL values and no entry at all would have the same return > result. Yes this is a problem. I did a little research how other libraries solve this problem. Oh man, there are many of them. Far the most libraries return the value directly [1], some of them use a function to check if the key exists and set the value part as a side effect [2] and a third group uses an approach were creation is a side effect of lookup (sometimes controlled with a flag) and always return an key/value pair [3]. Glib for example use approaches [1] and [2]. Our current approach looks like a mixture of all these 3 cases. >From the principle of least surprise, I suggest to let hash_get return a value pointer directly and have the ambiguity of NULL value and no entry, and have a hash_get_bucket which returns a pointer to the bucket. void * hash_get(Interp * interpreter, HASH *hash, void *key); HASHBUCKET * hash_get_bucket(Interp * interpreter, HASH *hash, void *key); Some other note. Didn't we decided some time ago to use only ALLCAPS types in cases were they are abbreviations. So the name would better be Hash and HashBucket. > Additionally the returned bucket has the key inside, which could be > useful. In cases where two keys compare equal but are not equal bitwise this is indeed nice. bye boe [1] http://oss.software.ibm.com/cvs/icu/icu/source/common/uhash.h?rev=1.24 http://developer.gnome.org/doc/API/2.0/glib/glib-Hash-Tables.html http://apr.apache.org/docs/apr/group__apr__hash.html http://www.w3.org/Library/src/HTHash.html http://mission.base.com/peter/source/pbl/doc/ http://judy.sourceforge.net/JudySL_3x.htm http://www.ipd.bth.se/ska/sim_home/libghthash_mk2_doc/ght__hash__table_8h.html http://dodgysoftware.net/ht/ http://chilli.degnet.de/~e_decker/hashtable/ [2] http://developer.gnome.org/doc/API/2.0/glib/glib-Hash-Tables.html http://www-2.cs.cmu.edu/~bwolen/fmcad98/packages/tiger/tgrlib/utilhash.html http://www.ohse.de/uwe/strhash/libstrhash.html http://www.stalphonsos.com/~attila/libgram/docs/hash_8h.html [3] http://www.gnu.org/manual/bfd-2.9.1/html_node/bfd_43.html http://www.gnu.org/software/libc/manual/html_node/Hash-Search-Function.html http://www.tcl.tk/man/tcl8.2.3/TclLib/Hash.htm -- Juergen Boemmels [EMAIL PROTECTED] Fachbereich Physik Tel: ++49-(0)631-205-2817 Universitaet Kaiserslautern Fax: ++49-(0)631-205-3906 PGP Key fingerprint = 9F 56 54 3D 45 C1 32 6F 23 F6 C7 2F 85 93 DD 47
