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//! Non-empty hash map and hash set implementations based on [`indexmap::IndexMap`] and
//! [`indexmap::IndexSet`] respectively, which are guaranteed to be non-empty by the type system of
//! Rust.
//!
//! [![pipeline status](https://gitlab.com/mexus/non-empty-collections/badges/master/pipeline.svg)](https://gitlab.com/mexus/non-empty-collections/commits/master)
//! [![crates.io](https://img.shields.io/crates/v/non-empty-collections.svg)](https://crates.io/crates/non-empty-collections)
//! [![docs.rs](https://docs.rs/non-empty-collections/badge.svg)](https://docs.rs/non-empty-collections)
//!
//! [[Release docs]](https://docs.rs/non-empty-collections/)
//!
//! [[Master docs]](https://mexus.gitlab.io/non-empty-collections/non_empty_collections/)
//!
//! Currently not all the methods of IndexMap or IndexSet are ported to NonEmptyIndexMap and
//! NonEmptyIndexSet, so if you are missing something, PRs are welcome! :)
//!
//! Right now both implementations are too naïve: non-emptiness is achieved by declaring map and
//! set types as a pair of an element and the rest of the collection. While the idea itself is not
//! bad, it adds an additional overhead on basically every operation since we have to execute
//! everything twice: on the first element and then on the rest.
//!
//! Both collections are coming with serde de- and serializers, but if you don't need them and want
//! to save some space and/or compilation time you can always disable it by disabling a feature
//! `serde_support` (which is *on* by default).

#![deny(missing_docs)]

extern crate indexmap;

#[cfg(feature = "serde_support")]
extern crate serde;

mod error;
pub mod index_map;
pub mod index_set;

/// Estimates a size of an interator using a *size hint* as `(lower + upper)/2`.
fn estimated_size(i: &impl Iterator) -> Option<usize> {
    let (lower, upper) = i.size_hint();
    upper.map(|upper| (upper + lower) / 2)
}

pub use error::Error;
pub use index_map::NonEmptyIndexMap;
pub use index_set::NonEmptyIndexSet;