use std::fmt::Debug;
use super::*;
#[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
pub enum Data {
Index(Vec<(Key, PageID)>),
Leaf(Vec<(Key, Value)>),
}
impl Data {
pub fn len(&self) -> usize {
match *self {
Data::Index(ref ptrs) => ptrs.len(),
Data::Leaf(ref items) => items.len(),
}
}
pub fn split(&self, lhs_prefix: &[u8]) -> (Key, Data) {
fn split_inner<T>(
xs: &[(Key, T)],
lhs_prefix: &[u8],
) -> (Key, Vec<(Key, T)>)
where T: Clone + Debug + Ord
{
let mut decoded_xs: Vec<_> = xs.iter()
.map(|&(ref k, ref v)| {
let decoded_k = prefix_decode(lhs_prefix, &*k);
(decoded_k, v.clone())
})
.collect();
decoded_xs.sort();
let (_lhs, rhs) = decoded_xs.split_at(decoded_xs.len() / 2 + 1);
let split = rhs.first().unwrap().0.clone();
let rhs_data: Vec<_> = rhs.iter()
.map(|&(ref k, ref v)| {
let new_k = prefix_encode(&*split, k);
(new_k, v.clone())
})
.collect();
(split, rhs_data)
}
match *self {
Data::Index(ref ptrs) => {
let (split, rhs) = split_inner(ptrs, lhs_prefix);
(split, Data::Index(rhs))
}
Data::Leaf(ref items) => {
let (split, rhs) = split_inner(items, lhs_prefix);
(split, Data::Leaf(rhs))
}
}
}
pub fn drop_gte(&mut self, at: &Bound, prefix: &[u8]) {
let bound = at.inner();
match *self {
Data::Index(ref mut ptrs) => {
ptrs.retain(|&(ref k, _)| {
let decoded_k = prefix_decode(prefix, &*k);
&*decoded_k < bound
})
}
Data::Leaf(ref mut items) => {
items.retain(|&(ref k, _)| {
let decoded_k = prefix_decode(prefix, &*k);
&*decoded_k < bound
})
}
}
}
pub fn leaf(&self) -> Option<Vec<(Key, Value)>> {
match *self {
Data::Index(_) => None,
Data::Leaf(ref items) => Some(items.clone()),
}
}
pub fn leaf_ref(&self) -> Option<&Vec<(Key, Value)>> {
match *self {
Data::Index(_) => None,
Data::Leaf(ref items) => Some(items),
}
}
}