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use core::borrow::Borrow;
use core::cmp::Ordering;
use super::node::{marker, ForceResult::*, Handle, NodeRef};
use SearchResult::*;
pub enum SearchResult<BorrowType, K, V, FoundType, GoDownType> {
Found(Handle<NodeRef<BorrowType, K, V, FoundType>, marker::KV>),
GoDown(Handle<NodeRef<BorrowType, K, V, GoDownType>, marker::Edge>),
}
pub enum IndexResult {
KV(usize),
Edge(usize),
}
impl<BorrowType: marker::BorrowType, K, V> NodeRef<BorrowType, K, V, marker::LeafOrInternal> {
pub fn search_tree<Q: ?Sized>(
mut self,
key: &Q,
) -> SearchResult<BorrowType, K, V, marker::LeafOrInternal, marker::Leaf>
where
Q: Ord,
K: Borrow<Q>,
{
loop {
self = match self.search_node(key) {
Found(handle) => return Found(handle),
GoDown(handle) => match handle.force() {
Leaf(leaf) => return GoDown(leaf),
Internal(internal) => internal.descend(),
},
}
}
}
}
impl<BorrowType, K, V, Type> NodeRef<BorrowType, K, V, Type> {
pub fn search_node<Q: ?Sized>(self, key: &Q) -> SearchResult<BorrowType, K, V, Type, Type>
where
Q: Ord,
K: Borrow<Q>,
{
match self.find_index(key) {
IndexResult::KV(idx) => Found(unsafe { Handle::new_kv(self, idx) }),
IndexResult::Edge(idx) => GoDown(unsafe { Handle::new_edge(self, idx) }),
}
}
fn find_index<Q: ?Sized>(&self, key: &Q) -> IndexResult
where
Q: Ord,
K: Borrow<Q>,
{
let node = self.reborrow();
let keys = node.keys();
for (i, k) in keys.iter().enumerate() {
match key.cmp(k.borrow()) {
Ordering::Greater => {}
Ordering::Equal => return IndexResult::KV(i),
Ordering::Less => return IndexResult::Edge(i),
}
}
IndexResult::Edge(keys.len())
}
}