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- Simplify Number::operator/= to use more constexpr values, and fewer
variations.
- Most significantly, rounding up doesn't need more precision, it only
needs to know if there's a remainder after the current precision work
is done. Tracked similarly Guard::xbit_.
- Build a constexpr lookup array for powers of 10. Only a handful of
values are used, but since it's built at compile time, and constexpr,
unused values do not affect memory or performance.
Basics
Utility functions and classes.
The module xrpl/basics should contain no dependencies on other modules.
Choosing an xrpld container.
-
std::vector- For ordered containers with most insertions or erases at the end.
-
std::deque- For ordered containers with most insertions or erases at the start or end.
-
std::list- For ordered containers with inserts and erases to the middle.
- For containers with iterators stable over insert and erase.
- Generally slower and bigger than
std::vectororstd::dequeexcept for those cases.
-
std::set- For sorted containers.
-
xrpl::hash_set- Where inserts and contains need to be O(1).
- For "small" sets,
std::setmight be faster and smaller.
-
xrpl::hardened_hash_set- For data sets where the key could be manipulated by an attacker in an attempt to mount an algorithmic complexity attack: see http://en.wikipedia.org/wiki/Algorithmic_complexity_attack
The following container is deprecated
std::unordered_set- Use
xrpl::hash_setinstead, which uses a better hashing algorithm. - Or use
xrpl::hardened_hash_setto prevent algorithmic complexity attacks.