class CompactATypeArray : use only on primitive data types
Provides a compact way to store information that is indexed by Unicode
values, such as character properties, types, keyboard values, etc.This
is very useful when you have a block of Unicode data that contains
significant values while the rest of the Unicode data is unused in the
application or when you have a lot of redundance, such as where all 21,000
Han ideographs have the same value. However, lookup is much faster than a
hash table.
A compact array of any primitive data type serves two purposes:
- Fast access of the indexed values.
- Smaller memory footprint.
A compact array is composed of a index array and value array. The index
array contains the indices of Unicode characters to the value array.