To better distinguish between entry->k and entry->v being const within linkhash, but non-const outside, add lh_entry_v() and lh_entry_k() accessors.
Make lh_entry->k const.
The user might want to use the userdata for something different, so the
serializer should ignore it by default.
Explicitly setting the serializer to json_object_double_to_json_string will
still make it interpret the userdata as a format string.
smalls strings inside json_objects had a high overhead because dynamic
memory allocation was needed for each of them. This also meant that the
pointer needed to be updated. This is now changed so that small strings
can directly be stored inside the json_object. Note that on the regular
64 bit machines a pointer takes 8 bytes. So even without increasing
memory, we could store string up to 7 bytes directly inside the object.
The max size is configurable. I have selected up to 31 bytes (which
means a buffer of 32 including the NUL byte). This brings a 24-bytes
memory overhead, but I consider that still useful because the memory
allocator usually also has quite some overhead (16 bytes) for
dyn alloced memory blocks. In any case, the max buffer size can be
tweaked via #define.
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no longer maintained; cache performance can be better, load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.
Arrays can already be sorted with json_object_array_sort() which uses
qsort() of the standard C library. This adds a counterpart using the
bsearch() from C.
sscanf is always a potential problem when converting numeric
values as it does not correctly handle over- and underflow
(or at least gives no indication that it has done so).
This change converts json_object_get_double() to use strtod()
according to CERT guidelines.
* Return value of json_object_object_add() changed from void to int.
Return value now indicates success or failure.
* Check whether allocations are successful.
* Do not exit program from within the library.
