quadtree_rs 0.1.3

Point/region Quadtree with support for overlapping regions.
Documentation 
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// Copyright 2019 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

//! A view into a single entry in the Quadtree.
// Influenced by https://doc.rust-lang.org/std/collections/hash_map/enum.Entry.html.

#[cfg(feature = "serde")]
use serde::{Deserialize, Serialize};
use {
    crate::{area::Area, point::Point},
    num::PrimInt,
    std::default::Default,
};

/// A region/value association in the [`Quadtree`].
///
/// `Entry` is used both for read-only access into a quadtree (i.e. [`.get()`]) and as the return
/// type for mutating operations (i.e. [`.delete()`], which returns `iter::IntoIter<U, V>`, which
/// is iterable over _former_ `Entry<U, V>` entries).
///
/// [`.get()`]: ../struct.Quadtree.html#method.get
/// [`.delete()`]: ../struct.Quadtree.html#method.delete
/// ```
/// use quadtree_rs::{
///   area::AreaBuilder,
///   Quadtree,
/// };
///
/// let mut qt = Quadtree::<u32, f64>::new(4);
/// let region_a = AreaBuilder::default()
///     .anchor((1, 1).into())
///     .dimensions((3, 2))
///     .build().unwrap();
///
/// qt.insert(region_a, 4.56_f64);
///
/// // Calling Quadtree::delete() on a region in the tree clears that region of the tree and returns the region/value associations which were deleted.
///
/// let region_b = AreaBuilder::default()
///     .anchor((2, 1).into())
///     .build().unwrap();
///
/// // The iterator contains Entry<U, V> structs.
/// let mut returned_entries = qt.delete(region_b);
///
/// let entry = returned_entries.next().unwrap();
///
/// assert_eq!(entry.anchor().x(), 1);
/// assert_eq!(entry.anchor().y(), 1);
/// assert_eq!(entry.width(), 3);
/// assert_eq!(entry.height(), 2);
///
/// assert_eq!(entry.value_ref(), &4.56);
/// ```
///
/// [`Quadtree`]: ../struct.Quadtree.html
// TODO(ambuc): Entry should hold Box<V> for better return-by-value semantics.
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
#[derive(Debug, PartialEq, Eq)]
pub struct Entry<U, V>
where
    U: PrimInt + Default,
{
    region: Area<U>,
    value: V,
    handle: u64,
}
impl<U, V> Entry<U, V>
where
    U: PrimInt + Default,
{
    // pub

    /// The returned region.
    pub fn area(&self) -> Area<U> {
        self.region
    }

    /// The top-left coordinate of the returned region.
    pub fn anchor(&self) -> Point<U> {
        self.area().anchor()
    }

    /// The width of the returned region.
    pub fn width(&self) -> U {
        self.dimensions().0
    }

    /// The height of the returned region.
    pub fn height(&self) -> U {
        self.dimensions().1
    }

    /// A mutable accessor to the returned value.
    pub fn value_mut(&mut self) -> &mut V {
        &mut self.value
    }

    /// A reference to the returned value.
    pub fn value_ref(&self) -> &V {
        &self.value
    }

    // pub(crate)

    pub(crate) fn new((region, value): (Area<U>, V), handle: u64) -> Self {
        Self {
            region,
            value,
            handle,
        }
    }

    pub(crate) fn dimensions(&self) -> (U, U) {
        self.area().dimensions()
    }

    pub fn handle(&self) -> u64 {
        self.handle
    }
}