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use std::boxed::Box;
use super::Prefix;
use crate::{
concrete::{Hostmask, Netmask, PrefixOrdering},
traits::{Address as _, Afi, Prefix as _, PrefixLength as _},
};
mod from;
mod gluemap;
mod iter;
mod ops;
use self::gluemap::GlueMap;
pub(super) use self::iter::{Children, Ranges};
enum Direction {
Left,
Right,
}
#[derive(Clone, Debug)]
pub struct Node<A: Afi> {
prefix: Prefix<A>,
gluemap: GlueMap<A>,
left: Option<Box<Node<A>>>,
right: Option<Box<Node<A>>>,
}
impl<A: Afi> Node<A> {
const fn new(prefix: Prefix<A>, gluemap: GlueMap<A>) -> Self {
Self {
prefix,
gluemap,
left: None,
right: None,
}
}
const fn new_glue(prefix: Prefix<A>) -> Self {
Self::new(prefix, GlueMap::ZERO)
}
pub fn boxed(self) -> Box<Self> {
Box::new(self)
}
pub const fn prefix(&self) -> &Prefix<A> {
&self.prefix
}
pub fn is_glue(&self) -> bool {
self.gluemap == GlueMap::ZERO
}
pub fn add(mut self: Box<Self>, mut other: Box<Self>) -> Box<Self> {
match self.prefix().compare(other.prefix()) {
PrefixOrdering::Equal => {
self.gluemap |= other.gluemap;
if let Some(child) = other.left {
self = self.add(child);
}
if let Some(child) = other.right {
self = self.add(child);
}
self
}
PrefixOrdering::Subprefix(common) => {
// mask glue map for prefix lengths already present
other.gluemap &= !self.gluemap;
match other.branch_direction(&common) {
Direction::Left => {
if let Some(child) = self.left {
let new_child = child.add(other);
self.left = Some(new_child);
} else {
self.left = Some(other);
}
}
Direction::Right => {
if let Some(child) = self.right {
let new_child = child.add(other);
self.right = Some(new_child);
} else {
self.right = Some(other);
}
}
};
self
}
PrefixOrdering::Superprefix(common) => {
self.gluemap &= !other.gluemap;
match self.branch_direction(&common) {
Direction::Left => {
if let Some(child) = other.left {
let new_child = child.add(self);
other.left = Some(new_child);
} else {
other.left = Some(self);
}
}
Direction::Right => {
if let Some(child) = other.right {
let new_child = child.add(self);
other.right = Some(new_child);
} else {
other.right = Some(self);
}
}
};
other
}
PrefixOrdering::Divergent(common) => {
// unwrap is safe here because common < P::MAX_LENGTH
let mut glue = Self::new_glue(common).boxed();
match self.branch_direction(&common) {
Direction::Left => {
glue.left = Some(self);
glue.right = Some(other);
}
Direction::Right => {
glue.left = Some(other);
glue.right = Some(self);
}
};
glue
}
}
}
pub fn remove(mut self: Box<Self>, other: &mut Self) -> Box<Self> {
if let Some(mut child) = other.left.take() {
self = self.remove(&mut child);
}
if let Some(mut child) = other.right.take() {
self = self.remove(&mut child);
}
match self.prefix().compare(other.prefix()) {
PrefixOrdering::Superprefix(_) | PrefixOrdering::Equal => {
// clear gluemap bits and recurse down
self.gluemap &= !other.gluemap;
if let Some(child) = self.left.take() {
self.left = Some(child.remove(other));
};
if let Some(child) = self.right.take() {
self.right = Some(child.remove(other));
};
}
PrefixOrdering::Subprefix(common) => {
let deaggr_mask = self.gluemap & other.gluemap;
if deaggr_mask != GlueMap::ZERO {
// deaggregate matching subprefixes before recursing
self.gluemap &= !deaggr_mask;
self = self
.prefix
.subprefixes(other.prefix.length())
.unwrap() // safe because `other` is a subprefix of `self`.
.map(|p| Box::new(Self::new(p, deaggr_mask)))
.fold(self, Self::add);
}
match other.branch_direction(&common) {
Direction::Left => {
if let Some(child) = self.left.take() {
self.left = Some(child.remove(other));
};
}
Direction::Right => {
if let Some(child) = self.right.take() {
self.right = Some(child.remove(other));
};
}
}
}
PrefixOrdering::Divergent(_) => (),
};
self
}
pub fn aggregate(mut self: Box<Self>, mut mask: Option<GlueMap<A>>) -> Option<Box<Self>> {
// set mask to zero if None given
if mask.is_none() {
mask = Some(GlueMap::ZERO);
}
// mask is the union of gluemaps of all parent nodes.
// if the intersection of mask and self.gluemap is not zero
// then self represents one or more deduplicate prefixes.
//
// unset mask bits in self.gluemap
self.gluemap &= !mask.unwrap();
// set remaining bits of self.gluemap in mask
*mask.as_mut().unwrap() |= self.gluemap;
// recurse child nodes
if let Some(child) = self.left.take() {
self.left = child.aggregate(mask);
}
if let Some(child) = self.right.take() {
self.right = child.aggregate(mask);
}
// if both left and right child nodes exist, and have the same
// length == self.prefix.length() + 1, then any bits set in both
// child gluemaps can be aggregated into self.gluemap.
//
match (
self.prefix().length().increment(),
&mut self.right,
&mut self.left,
) {
(Ok(len), Some(l), Some(r))
if l.prefix().length() == len && r.prefix().length() == len =>
{
// get the bits set in both child gluemaps
let aggr_bits = l.gluemap & r.gluemap;
// unset the bits in each child gluemap
l.gluemap &= !aggr_bits;
r.gluemap &= !aggr_bits;
// set them in self.gluemap
self.gluemap |= aggr_bits;
// check whether any aggregation occurred
if aggr_bits == GlueMap::ZERO {
// no aggregation occurred, so self may now be unnecessary glue.
self.clean()
} else {
// left or right may now be unnecessary glue.
// also, since some aggregation into self.gluemap occurred, self
// cannot be a glue node.
if let Some(child) = self.left.take() {
self.left = child.clean();
};
if let Some(child) = self.right.take() {
self.right = child.clean();
};
Some(self)
}
}
_ => self.clean(),
}
}
fn clean(self: Box<Self>) -> Option<Box<Self>> {
if self.gluemap == GlueMap::ZERO {
match (&self.left, &self.right) {
(None, None) => None,
(Some(_), None) => self.left,
(None, Some(_)) => self.right,
_ => Some(self),
}
} else {
Some(self)
}
}
pub fn search(&self, qnode: &Self) -> Option<&Self> {
match self.prefix().compare(qnode.prefix()) {
PrefixOrdering::Equal | PrefixOrdering::Subprefix(_)
if self.gluemap & qnode.gluemap == qnode.gluemap =>
{
Some(self)
}
PrefixOrdering::Subprefix(common) => match qnode.branch_direction(&common) {
Direction::Left => self.left.as_ref().and_then(|child| child.search(qnode)),
Direction::Right => self.right.as_ref().and_then(|child| child.search(qnode)),
},
_ => None,
}
}
fn intersect_nodes(&self, qnode: &Self) -> Option<Box<Self>> {
match self.prefix().compare(qnode.prefix()) {
PrefixOrdering::Divergent(_) => None,
cmp => {
let prefix = if let PrefixOrdering::Subprefix(_) = cmp {
qnode.prefix()
} else {
self.prefix()
};
let mut new = Box::new(Self::new(*prefix, self.gluemap & qnode.gluemap));
if let Some(child) = &self.left {
if let Some(intersect_child) = child.intersect_nodes(qnode) {
new = new.add(intersect_child);
};
};
if let Some(child) = &self.right {
if let Some(intersect_child) = child.intersect_nodes(qnode) {
new = new.add(intersect_child);
};
};
Some(new)
}
}
}
fn branch_direction(&self, from: &Prefix<A>) -> Direction {
let mask = Hostmask::from(from.length())
& Netmask::from(
from.length()
.increment()
// ok to unwrap, because `from.length() < MAX_LENGTH`.
.unwrap(),
);
if (self.prefix().network() & mask).is_unspecified() {
Direction::Left
} else {
Direction::Right
}
}
pub fn ranges(&self) -> Ranges<'_, A> {
self.into()
}
pub fn children(&self) -> Children<'_, A> {
self.into()
}
}
#[cfg(test)]
mod tests;