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use crate::quad::{Quad, Node};
/// Represents a context with shared state.
pub struct Ctx();
impl Ctx {
/// Creates a new uninitialized context.
pub fn new_empty() -> Self {
Ctx()
}
/// Combines 4 child node representations into a single representation
/// Using a neural network.
pub fn combine<B>(&mut self, compr: [B; 4]) -> B {
todo!("Build new B from 4 child B");
}
/// Compresses a base-level cell into a vector.
pub fn compress_base<A, B>(&mut self, base: A) -> B {
todo!("Turn Base Cell into a vector B");
}
/// Compresses a single node into a vector representation.
/// Returns `None` if node has already been compressed and trimmed from tree.
/// To recover a trimmed node, use `expand` on the compressed representation.
pub fn compress<A: Default, B: Copy>(&mut self, quad: &Quad<A, B>) -> Option<B> {
match quad {
Quad::Base(b) => Some(self.compress_base(b)),
Quad::Node(n) => Some(
self.combine([
n[0].compr,
n[1].compr,
n[2].compr,
n[3].compr,
])
),
Quad::Cached => None,
}
}
/// Compresses a base-level cell into a vector.
fn expand_base<A: Default, B: Copy>(&mut self, compr: B) -> A {
todo!("Turn compressed B into the A that made it");
}
fn expand_node<B>(&mut self, compr: B) -> [B; 4] {
todo!("Turn compressed B into 4 child B that made it");
}
/// Expands the compressed representation of a node into a node with 4 children.
pub fn expand<A: Default, B: Copy>(&mut self, mut compr: Node<A, B>) -> Node<A, B> {
match compr.data {
// Can't expand a base node.
Quad::Base(_) => {
debug_assert!(compr.depth == 0, "Tree is malformed at the leaves");
compr
},
// No-op if node is already expanded.
Quad::Node(_) => {
debug_assert!(compr.depth != 0, "Tree is malformed along the trunk");
compr
},
Quad::Cached => {
// Expand and repace the current node data.
compr.data = if compr.depth == 0 {
// Base case.
Quad::Base(self.expand_base(compr.compr))
} else {
// Expand the children into their corresponding vectors.
let c = self.expand_node(compr.compr);
// Pack the children into a new Node.
let new_depth = compr.depth - 1;
let children = [
Node::new_cached(c[0], new_depth),
Node::new_cached(c[1], new_depth),
Node::new_cached(c[2], new_depth),
Node::new_cached(c[3], new_depth),
];
// Heap-allocate the node lol.
Quad::Node(Box::new(children))
};
// The updated node.
compr
},
}
}
}
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