jaburns

/*
Copyright 2021 Jeremy Burns

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR O

kyren

use std::{iter, slice, vec};
use std::iter::FromIterator;

/// A unique identifier with an associated usize index.  Indexes are valued proportional to the
/// number of indexes allocated, are reused after being freed, and do not grow without bound.  When
/// an index is re-used, an associated "generation" is incremented, so that within the life of a
/// single allocator, no two GenerationalIndex values will ever be equal.  Since the indexes do not
/// grow without bound, GenerationalIndex values are particularly suited to being stored by their
/// index in extremely fast contiguous arrays.
#[derive(PartialEq, Eq, PartialOrd, Ord, Hash, Clone, Copy, Debug)]