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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 fn search_tree<BorrowType, K, V, Q: ?Sized>(
mut node: NodeRef<BorrowType, K, V, marker::LeafOrInternal>,
key: &Q,
) -> SearchResult<BorrowType, K, V, marker::LeafOrInternal, marker::Leaf>
where
Q: Ord,
K: Borrow<Q>,
{
loop {
match search_node(node, key) {
Found(handle) => return Found(handle),
GoDown(handle) => match handle.force() {
Leaf(leaf) => return GoDown(leaf),
Internal(internal) => {
node = internal.descend();
continue;
}
},
}
}
}
pub fn search_node<BorrowType, K, V, Type, Q: ?Sized>(
node: NodeRef<BorrowType, K, V, Type>,
key: &Q,
) -> SearchResult<BorrowType, K, V, Type, Type>
where
Q: Ord,
K: Borrow<Q>,
{
match search_linear(&node, key) {
(idx, true) => Found(Handle::new_kv(node, idx)),
(idx, false) => SearchResult::GoDown(Handle::new_edge(node, idx)),
}
}
pub fn search_linear<BorrowType, K, V, Type, Q: ?Sized>(
node: &NodeRef<BorrowType, K, V, Type>,
key: &Q,
) -> (usize, bool)
where
Q: Ord,
K: Borrow<Q>,
{
for (i, k) in node.keys().iter().enumerate() {
match key.cmp(k.borrow()) {
Ordering::Greater => {}
Ordering::Equal => return (i, true),
Ordering::Less => return (i, false),
}
}
(node.keys().len(), false)
}