Alvaro Herrera wrote:
Marko Kreen escribió:
On 3/30/07, Alvaro Herrera <[EMAIL PROTECTED]> wrote:

In any case it's not likely that there are going to be thousands of
prepared statements, so is this really an issue?
I think the issue is here that its very common thing to do,
so open-coding it everywhere is waste, there should be some
utility function for that.

void hash_foreach(HTAB, void (*cb_func)(void *));

Extra points if you can implement a map() function for hashes ;-) (I
think it's called "mutator" in our sources for other kind of stuff)

I think it would be
void *hash_map(HTAB, void *(*map_func) (void *))

Not sure what the return value would be though :-( (Maybe this is
extra complication enough that it's not worth the hassle)

hash_map and hash_foreach seem like overkill to me, looping with hash_seq_search and doing stuff is simple enough that it doesn't really require any additional shorthands. Besides, to use them you'd always have to have a separate function and often a struct to pass down to the function, so it's not really any shorter or simpler.

What would be useful is a hash_seq_remove-function that removes the previous item returned by hash_seq_search without the overhead of recalculating the hash value.

While reviewing ITAGAKI's dead space map patch I noticed that he also added a hash_truncate function that removes all entries in the hash table, but unlike hash_destroy leaves the hash table intact. His implementation also calls hash_search(REMOVE) in a loop, which isn't the most efficient way to do it, but clearly there's need for more ways to empty a hash table.

--
  Heikki Linnakangas
  EnterpriseDB   http://www.enterprisedb.com

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