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use num_traits::{Bounded, Num, Signed, Zero};
use std::fmt::Debug;
/// Defines a number type that is compatible with rstar.
///
/// rstar works out of the box with the following standard library types:
/// - i32
/// - i64
/// - f32
/// - f64
///
/// This type cannot be implemented directly. Instead, it is just required to implement
/// all required traits from the `num_traits` crate.
///
/// # Example
/// ```
/// # extern crate num_traits;
/// use num_traits::{Bounded, Num, Signed};
///
/// #[derive(Clone, Copy, PartialEq, PartialOrd, Debug)]
/// struct MyFancyNumberType(f32);
///
/// impl Bounded for MyFancyNumberType {
/// // ... details hidden ...
/// # fn min_value() -> Self { MyFancyNumberType(Bounded::min_value()) }
/// #
/// # fn max_value() -> Self { MyFancyNumberType(Bounded::max_value()) }
/// }
///
/// impl Signed for MyFancyNumberType {
/// // ... details hidden ...
/// # fn abs(&self) -> Self { unimplemented!() }
/// #
/// # fn abs_sub(&self, other: &Self) -> Self { unimplemented!() }
/// #
/// # fn signum(&self) -> Self { unimplemented!() }
/// #
/// # fn is_positive(&self) -> bool { unimplemented!() }
/// #
/// # fn is_negative(&self) -> bool { unimplemented!() }
/// }
///
/// impl Num for MyFancyNumberType {
/// // ... details hidden ...
/// # type FromStrRadixErr = num_traits::ParseFloatError;
/// # fn from_str_radix(str: &str, radix: u32) -> Result<Self, Self::FromStrRadixErr> { unimplemented!() }
/// }
///
/// // There's a lot of traits that are still missing to make the above code compile,
/// // let's assume they are implemented. MyFancyNumberType type now readily implements
/// // RTreeNum and can be used with r-trees:
/// # fn main() {
/// use rstar::RTree;
/// let mut rtree = RTree::new();
/// rtree.insert([MyFancyNumberType(0.0), MyFancyNumberType(0.0)]);
/// # }
///
/// # impl num_traits::Zero for MyFancyNumberType {
/// # fn zero() -> Self { unimplemented!() }
/// # fn is_zero(&self) -> bool { unimplemented!() }
/// # }
/// #
/// # impl num_traits::One for MyFancyNumberType {
/// # fn one() -> Self { unimplemented!() }
/// # }
/// #
/// # impl std::ops::Mul for MyFancyNumberType {
/// # type Output = Self;
/// # fn mul(self, rhs: Self) -> Self { unimplemented!() }
/// # }
/// #
/// # impl std::ops::Add for MyFancyNumberType {
/// # type Output = Self;
/// # fn add(self, rhs: Self) -> Self { unimplemented!() }
/// # }
/// #
/// # impl std::ops::Sub for MyFancyNumberType {
/// # type Output = Self;
/// # fn sub(self, rhs: Self) -> Self { unimplemented!() }
/// # }
/// #
/// # impl std::ops::Div for MyFancyNumberType {
/// # type Output = Self;
/// # fn div(self, rhs: Self) -> Self { unimplemented!() }
/// # }
/// #
/// # impl std::ops::Rem for MyFancyNumberType {
/// # type Output = Self;
/// # fn rem(self, rhs: Self) -> Self { unimplemented!() }
/// # }
/// #
/// # impl std::ops::Neg for MyFancyNumberType {
/// # type Output = Self;
/// # fn neg(self) -> Self { unimplemented!() }
/// # }
/// #
/// ```
///
pub trait RTreeNum: Bounded + Num + Clone + Copy + Signed + PartialOrd + Debug {}
impl<S> RTreeNum for S where S: Bounded + Num + Clone + Copy + Signed + PartialOrd + Debug {}
/// Defines a point type that is compatible with rstar.
///
/// `Point` is implemented out of the box for arrays like `[f32; 2]` or `[f64; 7]` (up to dimension 8).
///
/// # Implementation example
/// Supporting a custom point type might look like this:
///
/// ```
/// use rstar::Point;
///
/// #[derive(Copy, Clone, PartialEq, Debug)]
/// struct IntegerPoint
/// {
/// x: i32,
/// y: i32
/// }
///
/// impl Point for IntegerPoint
/// {
/// type Scalar = i32;
/// const DIMENSIONS: usize = 2;
///
/// fn generate(generator: impl Fn(usize) -> Self::Scalar) -> Self
/// {
/// IntegerPoint {
/// x: generator(0),
/// y: generator(1)
/// }
/// }
///
/// fn nth(&self, index: usize) -> Self::Scalar
/// {
/// match index {
/// 0 => self.x,
/// 1 => self.y,
/// _ => unreachable!()
/// }
/// }
///
/// fn nth_mut(&mut self, index: usize) -> &mut Self::Scalar
/// {
/// match index {
/// 0 => &mut self.x,
/// 1 => &mut self.y,
/// _ => unreachable!()
/// }
/// }
/// }
/// ```
pub trait Point: Copy + Clone + PartialEq + Debug {
/// The number type used by this point type.
type Scalar: RTreeNum;
/// The number of dimensions of this point type.
const DIMENSIONS: usize;
/// Creates a new point value with given values for each dimension.
///
/// The value that each dimension should be initialized with is given by the parameter `generator`.
/// Calling `generator(n)` returns the value of dimension `n`, `n` will be in the range `0 .. Self::DIMENSIONS`.
fn generate(generator: impl Fn(usize) -> Self::Scalar) -> Self;
/// Returns a single coordinate of this point.
///
/// Returns the coordinate indicated by `index`. `index` is always smaller than `Self::DIMENSIONS`.
fn nth(&self, index: usize) -> Self::Scalar;
/// Mutable variant of [nth](#methods.nth).
fn nth_mut(&mut self, index: usize) -> &mut Self::Scalar;
}
impl<T> PointExt for T where T: Point {}
pub trait PointExt: Point {
fn new() -> Self {
Self::from_value(Zero::zero())
}
fn component_wise(
&self,
other: &Self,
f: impl Fn(Self::Scalar, Self::Scalar) -> Self::Scalar,
) -> Self {
Self::generate(|i| f(self.nth(i), other.nth(i)))
}
fn all_component_wise(
&self,
other: &Self,
f: impl Fn(Self::Scalar, Self::Scalar) -> bool,
) -> bool {
// TODO: Maybe do this by proper iteration
for i in 0..Self::DIMENSIONS {
if !f(self.nth(i), other.nth(i)) {
return false;
}
}
true
}
fn dot(&self, rhs: &Self) -> Self::Scalar {
self.component_wise(rhs, |l, r| l * r)
.fold(Zero::zero(), |acc, val| acc + val)
}
fn fold<T>(&self, start_value: T, f: impl Fn(T, Self::Scalar) -> T) -> T {
let mut accumulated = start_value;
// TODO: Maybe do this by proper iteration
for i in 0..Self::DIMENSIONS {
accumulated = f(accumulated, self.nth(i));
}
accumulated
}
fn from_value(value: Self::Scalar) -> Self {
Self::generate(|_| value)
}
fn min_point(&self, other: &Self) -> Self {
self.component_wise(other, min_inline)
}
fn max_point(&self, other: &Self) -> Self {
self.component_wise(other, max_inline)
}
fn length_2(&self) -> Self::Scalar {
self.fold(Zero::zero(), |acc, cur| cur * cur + acc)
}
fn sub(&self, other: &Self) -> Self {
self.component_wise(other, |l, r| l - r)
}
fn add(&self, other: &Self) -> Self {
self.component_wise(other, |l, r| l + r)
}
fn mul(&self, scalar: Self::Scalar) -> Self {
self.map(|coordinate| coordinate * scalar)
}
fn map(&self, f: impl Fn(Self::Scalar) -> Self::Scalar) -> Self {
Self::generate(|i| f(self.nth(i)))
}
fn distance_2(&self, other: &Self) -> Self::Scalar {
self.sub(other).length_2()
}
}
#[inline]
pub fn min_inline<S>(a: S, b: S) -> S
where
S: RTreeNum,
{
if a < b {
a
} else {
b
}
}
#[inline]
pub fn max_inline<S>(a: S, b: S) -> S
where
S: RTreeNum,
{
if a > b {
a
} else {
b
}
}
macro_rules! count_exprs {
() => (0);
($head:expr) => (1);
($head:expr, $($tail:expr),*) => (1 + count_exprs!($($tail),*));
}
macro_rules! implement_point_for_array {
($($index:expr),*) => {
impl<S> Point for [S; count_exprs!($($index),*)]
where
S: RTreeNum,
{
type Scalar = S;
const DIMENSIONS: usize = count_exprs!($($index),*);
fn generate(generator: impl Fn(usize) -> S) -> Self
{
[$(generator($index)),*]
}
fn nth(&self, index: usize) -> Self::Scalar {
self[index]
}
fn nth_mut(&mut self, index: usize) -> &mut Self::Scalar {
&mut self[index]
}
}
};
}
implement_point_for_array!(0, 1);
implement_point_for_array!(0, 1, 2);
implement_point_for_array!(0, 1, 2, 3);
implement_point_for_array!(0, 1, 2, 3, 4);
implement_point_for_array!(0, 1, 2, 3, 4, 5);
implement_point_for_array!(0, 1, 2, 3, 4, 5, 6);
implement_point_for_array!(0, 1, 2, 3, 4, 5, 6, 7);
implement_point_for_array!(0, 1, 2, 3, 4, 5, 6, 7, 8);