//! Temporal quantification using floating-point quantities.
//!
//! This crate provides quantification for spans of time. Unlike the standard
//! [`std::time`](https://doc.rust-lang.org/std/time/index.html) or the
//! [chrono](https://crates.io/crates/chrono) crate, this crate aims
//! to provide a fully featured Duration type which exposes and uses floating-point
//! values instead of integer ones.
//!
//! The existing solutions for time spans are high precision and good for displaying
//! and storing time values, but they are less than convenient to use in simulations or
//! mathematical contexts where a single fractional value in some unit is needed. Thus,
//! this crate was developed in order to fill that need while being maximally compatible
//! with the existing time libraries and not re-inventing the wheel. The interface aims to
//! be very similar to these libraries, just using floating point values so it may be
//! used as a near drop-in replacement for existing programs that
//! would benefit from floating point durations.
//!
//! The goal is to provide a type with the same set of features and flexibility as
//! `std::chrono::duration` in C++ while being "Rusty" in design.
//!
//! # Usage
//! Put this in your `Cargo.toml`:
//!
//! ```ignore
//! [dependencies]
//! float_duration = "0.3.3"
//! ```
//! # Overview
//!
//! This crate provides a single primary type:
//! [`FloatDuration`](duration/struct.FloatDuration.html) which represents an
//! arbitrary distance in time with no defined start or end point.
//! Internally, it stores a single `f64` holding the number of seconds the duration
//! represents, which can be negative for a "backward" duration. It provides accessors
//! methods to create and read the value in various units, as well as `impl`s for many
//! arithmetic operators in `std::ops`.
//!
//! ```rust
//! # use float_duration::*;
//! let timespan = FloatDuration::hours(2.5) + FloatDuration::seconds(30.0);
//! assert_eq!(timespan, FloatDuration::seconds(9030.0));
//! assert_eq!(timespan, FloatDuration::minutes(150.5));
//! ```
//! Additionally, a [`TimePoint`](duration/trait.TimePoint.html) trait is provided
//! for computing a `FloatDuration` between two objects representing a point in time.
//!
//! # Example Usage
//!
//! Compute the number of blocks in a larger interval:
//!
//! ```rust
//! use float_duration::FloatDuration;
//!
//! let time_block = FloatDuration::minutes(5.0);
//! let blocks_per_hour = FloatDuration::hours(1.0) / time_block;
//!
//! assert_eq!(blocks_per_hour, 12.0);
//! ```
//!
//! Perform a basic numerical integration of a mass on a spring:
//!
//! ```rust
//! use float_duration::FloatDuration;
//!
//! fn acceleration(m: f64, x: f64, t: FloatDuration) -> f64 {
//!     0.5*m*x*x
//! }
//!
//! fn main() {
//!     let mut sim_time = FloatDuration::zero();
//!     let end_time = FloatDuration::minutes(2.0);
//!     let dt = FloatDuration::milliseconds(50.0);
//!
//!     let mut x = 2.0;
//!     let mut v = 0.0;
//!     let m = 1.0;
//!
//!     while sim_time < end_time {
//!         let acc = acceleration(m, x, sim_time);
//!         v += acc*dt.as_seconds();
//!         x += v*dt.as_seconds();
//!         sim_time += dt;
//!     }
//! }
//! ```
//!
//! Run a function on 100 evenly spaced durations:
//!
//! ```rust
//! use float_duration::{FloatDuration, subdivide};
//!
//! fn compute_value(t: FloatDuration) -> f64 {
//!     t.as_seconds()*t.as_seconds()
//! }
//!
//! for time in subdivide(FloatDuration::zero(), FloatDuration::hours(1.0), 100) {
//!     println!("{}", compute_value(time));
//! }
//! ```
//!
//! # Library Support
//!
//! Currently `float_duration` can be compiled without any dependencies, but it
//! provides optional features for interfacing with other libraries.
//!
//! ## std::time
//! The `std::time` module is supported and `FloatDuration`
//! can be used directly with `SystemTime` and `Instant`:
//!
//! ```rust
//! // TimePoint needed for `float_duration_since`.
//! use float_duration::{FloatDuration, TimePoint};
//! use std::time::{Instant, SystemTime};
//!
//!
//! let start_time = Instant::now();
//! //Do lengthy operation...
//! let end_time = Instant::now();
//!
//! println!("Took {}.", end_time.float_duration_since(start_time).unwrap());
//! ```
//!
//! `FloatDuration` may also be converted to/from `std::time::Duration` via the
//! `to_std` and `from_std` methods.
//!
//! ## [approx](https://crates.io/crates/approx)
//! `FloatDuration` provides an implementation of `approx::ApproxEq`
//! for near-equality comparisons of `FloatDuration` if the `approx` feature is enabled.
//! Since `FloatDuration` uses floating point values, this should be the
//! preferred way to establish equality between two duration objects.
//!
//! ## [chrono](https://crates.io/crates/chrono)
//!
//! Similar to `std::time`, computing a `FloatDuration` between any two of the same type of
//! date or time objects
//! is supported via `TimePoint` trait impls, assuming the feature
//! "chrono" is enabled.
//! Additionally, `FloatDuration` objects can be converted to/from
//! `chrono::Duration` objects via the `to_chrono` and `from_chrono` methods.
//!
//! Note: if the `chrono` feature is enabled, the `time` feature must also be enabled
//! as `chrono` directly relies on some types defined in `time`.
//!
//! ```rust,ignore
//! use chrono::{UTC, TimeZone};
//! use float_duration::{TimePoint, FloatDuration};
//!
//! let date1 = UTC.ymd(2017, 5, 25).and_hms(10, 0, 0);
//! let date2 = UTC.ymd(2017, 5, 26).and_hms(12, 0, 0);
//!
//! assert_eq!(date2.float_duration_since(date1).unwrap(), FloatDuration::days(1.0) +
//!     FloatDuration::hours(2.0));
//! ```
//!
//! ## [serde](https://crates.io/crates/serde)
//!
//! `FloatDuration` supports serialization with `serde`. Presently, a `FloatDuration`
//! is serialized to a single `f64` value representing the number of seconds in the
//! duration.

#[cfg(feature = "chrono")]
extern crate chrono;
#[cfg(feature = "time")]
extern crate time;
#[cfg(feature = "approx")]
extern crate approx;
#[cfg(feature = "serde")]
extern crate serde;
#[cfg(all(test, feature = "serde"))]
extern crate serde_test;


pub mod duration;
pub mod error;
pub mod iter;

pub use duration::{FloatDuration, TimePoint, FromDuration, IntoDuration};
pub use error::OutOfRangeError;
pub use iter::{subdivide, subdivide_with_step};