ben-ph / fugit

`fugit` provides a comprehensive library of `Duration` and `Instant` for the handling of time in embedded systems, doing all it can at compile time.

fugit

fugit provides a comprehensive library of Duration and Instant for the handling of time in embedded systems, doing all it can at compile time.

This library is a heavily inspired of std::chrono's Duration from C++ which does all it can at compile time.

Aims

• no_std library with goals of user-friendliness and performance first
  • All methods are const fn that can be (i.e. non-trait methods)
  • Traits are only used for constraits. Implementations are monomophised throughout, for maximum const-ification
  • Operations are supported between different bases and backing storages instead of implementing custom traits
  • All constants needed for comparing or changing timebase are guaranteed compile time generated
• Support for both u32 and u64 backing storage with efficient instruction lowering on MCUs
  • On Cortex-M3 and up: no soft-impls pulled in for both u32 and u64 except when changing base on u64
  • Comparisons on u32 and u64 do not use division, only changing base with all constants calculated at compile time
• Selection of base happens at compile time, within the type-system.
  • A common problem is that run time changing of base robs us of a lot of optimization opportunities, but since there are no traits and short-hands select the correct base at compile time.
• Use of type-system for compile-time specifications
  • const generics are limited in what they can do at compile time, make expressing/constraining more complex behaviors difficult/impossible.