These items were used for statistics tracking, but no code at all
exists to consume them. By removing them we save
a) space
because they counters required space, and did so in each and every
json object
b) performance
because calloc() needs to write less data and the counters are
no longer maintained; cache performance can be better, load
on OS main memory is lighter
We could conditionally enable/disable these counters, but I have not
done this they were really nowhere used and it looked more like a
left-over from the import of hashtable code.
This also adds a new API json_global_set_string_hash() which permits
to select the hash function. The default one is the only one that was
previously present. So there are no changes to existing apps, and the
new hash function needs to be explicitely be opted in. Especially for
smaller strings, the perllike functions seems to be around twice as
fast as the other one, with similarly good results in value distribution.
Rainer Gerhards