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use crate::IsLessThan;
use crate::prelude::SkipList;
use crate::skiplist::{HEAD_INDEX, TAIL_INDEX};
use std::fmt::{Debug, Display};
impl<K, V> SkipList<K, V>
where
K: Debug + Display + Clone + IsLessThan,
V: Debug + Clone,
{
pub fn validate(&self) {
// Check ordering between nodes
self.validate_ordering();
self.assert_is_in_order();
// Check forward pointers at each level
for level in (0..=self.max_level).rev() {
self.validate_level(level);
}
}
fn validate_ordering(&self) {
let mut prev_index = HEAD_INDEX;
let mut current_index = if !self.head.forward.is_empty() {
self.head.forward[0]
} else {
TAIL_INDEX
};
while current_index != TAIL_INDEX {
let current_node = &self.nodes[current_index];
assert!(current_node.kv.is_some());
// Check prev pointer is consistent
assert_eq!(
current_node.prev,
prev_index,
"Node {:?} has incorrect prev pointer. Expected {:?}, got {:?}",
current_node.kv.as_ref().unwrap().0,
prev_index,
current_node.prev
);
// Check ordering between current and previous node
if prev_index != HEAD_INDEX {
if let Some(prev_node_key) = (prev_index != HEAD_INDEX && prev_index != TAIL_INDEX)
.then(|| self.nodes[prev_index].k())
{
assert!(
prev_node_key.is_less_than(current_node.k()),
"Ordering violation: {:?} should come before {:?}",
prev_node_key,
current_node.k()
);
assert!(
!current_node.k().is_less_than(prev_node_key),
"Ordering violation: {:?} should come after {:?}",
current_node.k(),
prev_node_key
);
}
}
prev_index = current_index;
current_index = if !current_node.forward.is_empty() {
current_node.forward[0]
} else {
TAIL_INDEX
};
}
// Check tail's prev pointer
assert_eq!(
self.tail.prev, prev_index,
"Tail's prev pointer incorrect. Expected {:?}, got {:?}",
prev_index, self.tail.prev
);
}
fn validate_level(&self, level: usize) {
let mut current_index = HEAD_INDEX;
let mut next_index = if level < self.head.forward.len() {
self.head.forward[level]
} else {
// Head doesn't have this level, so it should point directly to tail
TAIL_INDEX
};
if next_index == TAIL_INDEX {
assert!(self.current_level < level)
}
// Check head's forward pointer at this level
if level < self.head.forward.len() {
let next_node_idx = self.head.forward[level];
if next_node_idx != TAIL_INDEX {
let next_node = &self.nodes[next_node_idx];
assert!(
level < next_node.forward.len(),
"Head's level {} forward points to node {:?} that doesn't have this level",
level,
next_node.k()
);
}
}
while next_index != TAIL_INDEX {
let node = &self.nodes[next_index];
// Check node has this level
assert!(
level < node.forward.len(),
"Node {:?} is in level {} chain but doesn't have this level",
node.k(),
level
);
// Check next node's key is greater than current node's key
let next_next_index = node.forward[level];
if next_next_index != TAIL_INDEX {
let next_node = &self.nodes[next_next_index];
if !node.k().is_less_than(next_node.k()) {
self.debug_print();
}
dbg_assert!(
node.k().is_less_than(next_node.k()),
"Level {} ordering violation: {:?} should come before {:?}",
level,
node.k(),
next_node.k()
);
}
current_index = next_index;
next_index = node.forward[level];
}
// The last node at this level should point to tail
if current_index != HEAD_INDEX {
let forward = if current_index == HEAD_INDEX {
self.head.forward[level]
} else {
self.nodes[current_index].forward[level]
};
assert_eq!(
forward,
TAIL_INDEX,
"Last node {:?} at level {} should point to tail",
if current_index == HEAD_INDEX {
"HEAD"
} else {
"node"
},
level
);
}
}
pub fn assert_is_in_order(&self)
where
K: Debug + Clone + IsLessThan,
V: Debug + Clone,
{
let mut prev: Option<K> = None;
for (k, _) in self.iter() {
if let Some(prev_sample) = &prev {
if !prev_sample.is_less_than(k) {
self.debug_print()
}
assert!(
prev_sample.is_less_than(k),
"{prev_sample:?} is not less than {k:?}",
);
}
prev = Some(k.clone());
}
}
/// Print the SkipList in a visual tabulated format for debugging
pub fn debug_print(&self)
where
K: Display,
{
// Print levels from top to bottom, starting from max_level-1 down to 0
for level in (0..self.max_level).rev() {
if self.head.forward[level] == TAIL_INDEX {
continue;
}
print!("{level} ");
// Start from head node
let mut current_idx = HEAD_INDEX;
// Print connections at this level
loop {
// Get the forward index at this level
let next_idx = match current_idx {
HEAD_INDEX => {
print!("- ");
self.head.forward[0]
}
TAIL_INDEX => unreachable!(),
_ => {
let forward = &self.nodes[current_idx].forward;
// Check if this node has connections at this level
if level < forward.len() {
if forward[level] == TAIL_INDEX {
print!("> ");
} else {
print!("- ");
}
forward[0]
} else {
print!(" ");
// Skip nodes that don't exist at this level
if forward[0] == TAIL_INDEX {
break;
}
current_idx = forward[0];
continue;
}
}
};
// If we've reached the tail, exit the loop for this level
if next_idx == TAIL_INDEX {
break;
}
current_idx = next_idx;
}
println!();
}
// Print the node values on the bottom row
print!("< ");
// Start from the first real node (after head)
let mut current = self.next_pos_(HEAD_INDEX);
// Print each node's key
while let Some(idx) = current {
if idx != HEAD_INDEX && idx != TAIL_INDEX {
// Assuming keys can be displayed as single characters
print!("{} ", self.nodes[idx].k());
}
current = self.next_pos_(idx);
}
print!(">");
println!();
}
}
impl<K, V> SkipList<K, V>
where
K: Debug + Clone + IsLessThan,
V: Debug + Clone,
{
#[allow(dead_code)]
pub(super) fn print_path_(&self, path: &[usize]) {
let mut buff = String::new();
for i in path.iter() {
match *i {
HEAD_INDEX => buff.push('<'),
TAIL_INDEX => buff.push('>'),
_ => buff.push_str(format!("{i}").as_str()),
}
}
println!("path:{buff}");
}
}