mapping m_allocate(int size)
mapping m_allocate(int size, int width)
Reserve memory for a mapping.
<size> is the number of entries (i.e. keys) to reserve, <width> is
the number of data items per entry. If the optional width is
omitted, 1 is used as default.
This is useful only when you are going to construct a mapping
whose approximate size you know beforehand, to save overhead on
repeated memory allocations. If you don't fill in data for all the
allocated elements, any leftovers will be eventually freed some time
later (see remark below).
It is also useful if you want the mapping to have a certain width
even if you don't provide all the data items for the keys yet.
If the goal is just to create an empty mapping with a certain
width, the following notations can be used:
([ ]) : creates an empty mapping of width 1.
([:width ]) : creates an empty mapping the given <width>, where
<width> can be any expression yielding an integer result. In
fact this notation is compiled as 'm_allocate(0, width)' .
m_allocate(3, 7) -> mapping with 7 values per key, and with space
for 3 entries.
([:2*3 ]) -> same as m_allocate(0, 6)
Unused memory in the allocated mapping will be freed during the
so-called compacting of the mapping. This is done during the
data-cleanup or the garbage collection. The time between
data-cleanups is configurable by configure_driver().
Renamed from 'allocate_mapping' in LDMud 3.2.6.
The ([:width ]) notation was introduced in LDMud 3.2.9 / 3.3.208.
mappings(LPC), walk_mapping(E), get_type_info(E), m_reallocate(E)