//! # orx-split-vec
//!
//! A dynamic capacity vector with pinned elements.
//!
//! ## A. Motivation
//!
//! There might be various situations where pinned elements are helpful.
//!
//! * It is somehow required for async code, following [blog](https://blog.cloudflare.com/pin-and-unpin-in-rust) could be useful for the interested.
//! * It is a requirement to represent self-referential types with thin references.
//!
//! This crate focuses more on the latter. Particularly, it aims to make it safely and conveniently possible to build **self-referential collections** such as linked list, tree or graph.
//!
//! See [`PinnedVec`](https://crates.io/crates/orx-pinned-vec) for complete documentation.
//!
//! `SplitVec` is one of the pinned vec implementations which can be wrapped by an [`ImpVec`](https://crates.io/crates/orx-imp-vec) and allow building self referential collections.
//!
//! ## B. Comparison with `FixedVec`
//!
//! [`FixedVec`](https://crates.io/crates/orx-fixed-vec) is another `PinnedVec` implementation aiming the same goal but with different features. You may see the comparison in the table below.
//!
//! | **`FixedVec`**                                                               | **`SplitVec`**                                                                   |
//! |------------------------------------------------------------------------------|----------------------------------------------------------------------------------|
//! | Implements `PinnedVec` => can be wrapped by an `ImpVec`.                     | Implements `PinnedVec` => can be wrapped by an `ImpVec`.                         |
//! | Requires exact capacity to be known while creating.                          | Can be created with any level of prior information about required capacity.      |
//! | Cannot grow beyond capacity; panics when `push` is called at capacity.       | Can grow dynamically. Further, it provides control on how it must grow. |
//! | It is just a wrapper around `std::vec::Vec`; hence, has similar performance. | Performs additional tasks to provide flexibility; hence, slightly slower.        |
//!
//! ## C. Growth with Pinned Elements
//!
//! As the name suggests, `SplitVec` is a vector represented as a sequence of multiple contagious data fragments.
//!
//! The vector is at its capacity when all fragments are completely utilized. When the vector needs to grow further while at capacity, a new fragment is allocated. Therefore, growth does <ins>not</ins> require copying memory to a new memory location. Priorly pushed elements stay <ins>pinned</ins> to their memory locations.
//!
//! ### C.1. Available Growth Strategies
//!
//! The capacity of the new fragment is determined by the chosen growth strategy. Assume that `vec: SplitVec<_>` contains one fragment of capacity `C`, which is also the capacity of the vector since it is the only fragment. Assume, we used up all capacity; i.e., `vec.len() == vec.capacity()` (`C`). If we attempt to push a new element, `SplitVec` will allocate the second fragment with the following capacity:
//!
//! | **`Growth`** Strategy                   | 1st Fragment Capacity | 2nd Fragment Capacity | Vector Capacity |
//! |-----------------------------------------|-----------------------|-----------------------|-----------------|
//! | `Linear`                                | `C`                   | `C`                   | `2 * C`         |
//! | `Doubling`                              | `C`                   | `2 * C`               | `3 * C`         |
//!
//! `C` is set on initialization as a power of two for `Linear` and fixed to 4 for `Doubling` to allow for access time optimizations.
//!
//! ### C.2. Custom Growth Strategies
//!
//! In order to define a custom growth strategy, one needs to implement the `Growth` trait. Implementation is straightforward. The trait contains two methods. The following method is required:
//!
//! ```rust ignore
//! fn new_fragment_capacity<T>(&self, fragments: &[Fragment<T>]) -> usize
//! ```
//!
//! Notice that it takes as argument all priorly allocated fragments and needs to decide on the capacity of the new fragment.
//!
//! The second method `fn get_fragment_and_inner_indices<T>(&self, vec_len: usize, fragments: &[Fragment<T>], element_index: usize) -> Option<(usize, usize)>` has a default implementation and can be overwritten if the strategy allows for efficient computation of the indices.
//!
//! ## D. Examples
//!
//! ### D.1. Usage similar to `std::vec::Vec`
//!
//! ```rust
//! use orx_split_vec::prelude::*;
//!
//! let mut vec = SplitVec::new();
//!
//! vec.push(0);
//! vec.extend_from_slice(&[1, 2, 3]);
//! assert_eq!(vec, &[0, 1, 2, 3]);
//!
//! vec[0] = 10;
//! assert_eq!(10, vec[0]);
//!
//! vec.remove(0);
//! vec.insert(0, 0);
//!
//! assert_eq!(6, vec.iter().sum());
//!
//! assert_eq!(vec.clone(), vec);
//!
//! let stdvec: Vec<_> = vec.into();
//! assert_eq!(&stdvec, &[0, 1, 2, 3]);
//! ```
//!
//! ### D.2. `SplitVec` Specific Operations
//!
//! ```rust
//! use orx_split_vec::prelude::*;
//!
//! #[derive(Clone)]
//! struct MyCustomGrowth;
//! impl Growth for MyCustomGrowth {
//!     fn new_fragment_capacity<T>(&self, fragments: &[Fragment<T>]) -> usize {
//!         fragments.last().map(|f| f.capacity() + 1).unwrap_or(4)
//!     }
//! }
//!
//! // set the growth explicitly
//! let vec: SplitVec<i32, Linear> = SplitVec::with_linear_growth(4);
//! let vec: SplitVec<i32, Doubling> = SplitVec::with_doubling_growth();
//! let vec: SplitVec<i32, MyCustomGrowth> = SplitVec::with_growth(MyCustomGrowth);
//!
//! // methods revealing fragments
//! let mut vec = SplitVec::with_doubling_growth();
//! vec.extend_from_slice(&[0, 1, 2, 3]);
//!
//! assert_eq!(4, vec.capacity());
//! assert_eq!(1, vec.fragments().len());
//!
//! vec.push(4);
//! assert_eq!(vec, &[0, 1, 2, 3, 4]);
//!
//! assert_eq!(2, vec.fragments().len());
//! assert_eq!(4 + 8, vec.capacity());
//!
//! // SplitVec is not contagious; instead a collection of contagious fragments
//! // so it might or might not return a slice for a given range
//!
//! let slice: SplitVecSlice<_> = vec.try_get_slice(1..3);
//! assert_eq!(slice, SplitVecSlice::Ok(&[1, 2]));
//!
//! let slice = vec.try_get_slice(3..5);
//! // the slice spans from fragment 0 to fragment 1
//! assert_eq!(slice, SplitVecSlice::Fragmented(0, 1));
//!
//! let slice = vec.try_get_slice(3..7);
//! assert_eq!(slice, SplitVecSlice::OutOfBounds);
//!
//! // or the slice can be obtained as a vector of slices
//! let slice = vec.slice(0..3);
//! assert_eq!(1, slice.len());
//! assert_eq!(slice[0], &[0, 1, 2]);
//!
//! let slice = vec.slice(3..5);
//! assert_eq!(2, slice.len());
//! assert_eq!(slice[0], &[3]);
//! assert_eq!(slice[1], &[4]);
//!
//! let slice = vec.slice(0..vec.len());
//! assert_eq!(2, slice.len());
//! assert_eq!(slice[0], &[0, 1, 2, 3]);
//! assert_eq!(slice[1], &[4]);
//! ```
//!
//! ### D.3. Pinned Elements
//!
//! Unless elements are removed from the vector, the memory location of an element priorly pushed to the `SplitVec` <ins>never</ins> changes. This guarantee is utilized by `ImpVec` in enabling immutable growth to build self referential collections.
//!
//! ```rust
//! use orx_split_vec::prelude::*;
//!
//! let mut vec = SplitVec::with_linear_growth(3);
//!
//! // split vec with 1 item in 1 fragment
//! vec.push(42usize);
//! assert_eq!(&[42], &vec);
//! assert_eq!(1, vec.fragments().len());
//! assert_eq!(&[42], &vec.fragments()[0]);
//!
//! // let's get a pointer to the first element
//! let addr42 = &vec[0] as *const usize;
//!
//! // let's push 80 new elements
//! for i in 1..81 {
//!     vec.push(i);
//! }
//!
//! for (i, elem) in vec.iter().enumerate() {
//!     assert_eq!(if i == 0 { 42 } else { i }, *elem);
//! }
//!
//! // now the split vector is composed of 11 fragments each with a capacity of 10
//! assert_eq!(11, vec.fragments().len());
//!
//! // the memory location of the first element remains intact
//! assert_eq!(addr42, &vec[0] as *const usize);
//!
//! // we can safely (using unsafe!) dereference it and read the correct value
//! assert_eq!(unsafe { *addr42 }, 42);
//! ```
//!
//! ## E. Benchmarks
//!
//! Split vector variants have a comparable speed with (slightly faster than) the standard vector while growing and between 1 - 4 times slower with random access. The latter varies on the element size of the vector and the number of elements in the network. The gap diminishes as either of these factors increases. You may see the details below.
//!
//! Recall that the motivation of using a split vector is to get benefit of the pinned elements, rather than to be used in place of the standard vector which is highly efficient. The aim of the performance optimizations and benchmarks is to make sure that the gap is kept within acceptable limits.
//!
//! *All the numbers in tables below represent duration in milliseconds.*
//!
//! ### E.1. Grow
//!
//! *You may see the benchmark at [benches/grow.rs](https://github.com/orxfun/orx-split-vec/blob/main/benches/grow.rs).*
//!
//! The benchmark compares the build up time of vectors by pushing elements one by one. The baseline is the vector created by `std::vec::Vec::with_capacity` which has the perfect information on the number of elements to be pushed and writes to a contagious memory location. The compared variants are vectors created with no prior knowledge about capacity: `std::vec::Vec::new`, `SplitVec<_, Linear>` and `SplitVec<_, Doubling>`.
//!
//! <img src="https://raw.githubusercontent.com/orxfun/orx-split-vec/main/docs/img/bench_grow.PNG" alt="https://raw.githubusercontent.com/orxfun/orx-split-vec/main/docs/img/bench_grow.PNG" />
//!
//! Allowing copy-free growth, split vector variants have a comparable speed with `std::vec::Vec::with_capacity`, which can be around 1.5 times faster for u64-sized elements (2-3 times faster for 16-times-u64-sized elements) than `std::vec::Vec::new`. Overall, the differences can be considered insignificant in most cases.
//!
//! ### E.2. Random Access
//!
//! *You may see the benchmark at [benches/random-access.rs](https://github.com/orxfun/orx-split-vec/blob/main/benches/random-access.rs).*
//!
//! In this benchmark, we access vector elements by indices in a random order. Note that due to the fragmentation and additional book-keeping, `SplitVec` cannot be as fast as the standard `Vec`. However, `Linear` and `Doubling` growth strategies are optimized to minimize the gap as much as possible.
//!
//! <img src="https://raw.githubusercontent.com/orxfun/orx-split-vec/main/docs/img/bench_random_access.PNG" alt="https://raw.githubusercontent.com/orxfun/orx-split-vec/main/docs/img/bench_random_access.PNG" />
//!
//! For vectors having u64-sized elements, the split vector variants are around 2-4 times slower than the standard vector; the difference gets smaller as the number of elements increases. The difference further diminishes as the size of each element increases, as can be observed in 16-times-u64-sized elements (sometimes faster for unknown reasons:).
//!
//!
//! ## License
//!
//! This library is licensed under MIT license. See LICENSE for details.

#![warn(
    missing_docs,
    clippy::unwrap_in_result,
    clippy::unwrap_used,
    clippy::panic,
    clippy::panic_in_result_fn,
    clippy::float_cmp,
    clippy::float_cmp_const,
    clippy::missing_panics_doc,
    clippy::todo
)]

mod common_traits;
mod eq;
mod fragment;
mod growth;
mod new_split_vec;
mod pinned_vec;
mod resize_multiple;
mod slice;
mod split_vec;
#[cfg(test)]
pub(crate) mod test;

pub use common_traits::iterator::iter::Iter;
pub use fragment::fragment_struct::Fragment;
pub use growth::{doubling::Doubling, growth_trait::Growth, linear::Linear};
pub use slice::SplitVecSlice;
pub use split_vec::SplitVec;

/// The split-vec prelude, along with the `SplitVec`, imports
/// various growth startegies, iterators and finally the `orx_pinned_vec::PinnedVec` trait.
pub mod prelude;