[gcc 4.5 patch] Permit smaller hash tables for hash_map and hash_set

[Ian Lance Taylor]

Do we have a general policy for patches to hash_map and hash_set, now
that they have moved to include/backward?

I have a few patches to make them better in some circumstances.  These
ideas are incorporated in different from in the newer unordered_set and
unordered_map.  However, existing code still uses hash_map and hash_set,
so it may be useful to update them if we think that is OK.

Anyhow, this patch permits hash_{map,set} to be smaller.  This is useful
because not every hash table is large.  In unordered_{map,set} we permit
the number of buckets to start at 2.  This patch simply adds the number
5 at the start of the list of bucket counts for hash_{map,set}, so that
at least they don't have to start with 53 buckets.

Is this patch OK for gcc 4.5?

Ian


2009-02-06  Ian Lance Taylor  <iant@google.com>

	* include/backward/hashtable.h (_S_num_primes): Change to 29.
	(__stl_prime_list): Add 5 at the start of the list.


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