move bst into separate module
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parent
bcf9a3db19
commit
64bf67e67d
SSH key fingerprint:
SHA256:JyLeVWE4bF3tDnFeUpUaJsPsNlJyBldDGV/dIKSLyN8
2 changed files with 240 additions and 236 deletions
237
libtree/src/binary_search_tree.rs
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237
libtree/src/binary_search_tree.rs
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@ -0,0 +1,237 @@
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use core::fmt::Display;
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use crate::Stats;
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#[derive(Clone)]
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pub struct BinarySearchTreeNode {
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pub key: u64,
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pub left: BST,
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pub right: BST,
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}
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impl BinarySearchTreeNode {
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pub fn new(key: u64) -> Self {
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Self {
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key,
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left: BST(None),
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right: BST(None),
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}
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}
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pub fn height(&self) -> usize {
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match (&self.left.0, &self.right.0) {
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(None, None) =>
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1,
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(None, Some(right)) =>
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1 + right.height(),
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(Some(left), None) =>
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1 + left.height(),
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(Some(left), Some(right)) =>
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1 + (left.height()).max(right.height()),
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}
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}
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// https://stackoverflow.com/a/66661638
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fn replace_nth_char_ascii(s: &mut str, idx: usize, newchar: char) {
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let s_bytes: &mut [u8] = unsafe { s.as_bytes_mut() };
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assert!(idx < s_bytes.len());
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assert!(s_bytes[idx].is_ascii());
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assert!(newchar.is_ascii());
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// we've made sure this is safe.
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s_bytes[idx] = newchar as u8;
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}
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fn _print(&self, f: &mut std::fmt::Formatter<'_>, depth: usize, prefix: char, left_trace: &mut String, right_trace: &mut String) -> std::fmt::Result {
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if let Some(left) = &self.left.0 {
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left._print(f, depth + 1, '/', left_trace, right_trace)?;
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}
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if prefix == '/' {
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Self::replace_nth_char_ascii(left_trace, depth - 1, '|');
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}
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if prefix == '\\' {
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Self::replace_nth_char_ascii(right_trace, depth - 1, ' ');
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}
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if depth == 0 {
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write!(f, "-")?;
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}
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if depth > 0 {
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write!(f, " ")?;
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}
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if depth > 0 {
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for i in 0..(depth - 1) {
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if left_trace.chars().nth(i).unwrap() == '|' || right_trace.chars().nth(i).unwrap() == '|' {
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write!(f, "| ")?;
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} else {
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write!(f, " ")?;
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}
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}
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write!(f, "{}-", prefix)?;
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}
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writeln!(f, "[{}]", self.key)?;
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Self::replace_nth_char_ascii(left_trace, depth, ' ');
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if let Some(right) = &self.right.0 {
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Self::replace_nth_char_ascii(right_trace, depth, '|');
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right._print(f, depth + 1, '\\', left_trace, right_trace)?;
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}
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Ok(())
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}
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}
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#[derive(Clone)]
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pub struct BST(Option<Box<BinarySearchTreeNode>>);
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impl BST {
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pub fn insert(&mut self, key: u64) -> (bool, Stats) {
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let mut stats = Stats::new();
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if self.0.is_none() {
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stats.writes += 1;
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self.0 = Some(Box::new(BinarySearchTreeNode::new(key)));
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return (true, stats);
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}
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let mut current = self;
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while let Some(ref mut node) = current.0 {
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stats.reads += 1;
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use std::cmp::Ordering::*;
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stats.comparisons += 1;
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match node.key.cmp(&key) {
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Greater => {
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stats.reads += 1;
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current = &mut node.left;
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},
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Less => {
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stats.reads += 1;
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current = &mut node.right;
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},
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Equal => return (false, stats),
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}
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}
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stats.writes += 1;
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current.0 = Some(Box::new(BinarySearchTreeNode::new(key)));
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(true, stats)
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}
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pub fn delete(&mut self, key: u64) -> (bool, Stats) {
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let mut current: *mut BST = self;
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let mut stats = Stats::default();
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unsafe {
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while let Some(ref mut node) = (*current).0 {
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stats.reads += 1;
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use std::cmp::Ordering::*;
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stats.comparisons += 1;
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match node.key.cmp(&key) {
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Greater => {
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stats.reads += 1;
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current = &mut node.left;
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},
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Less => {
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stats.reads += 1;
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current = &mut node.right;
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},
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Equal => {
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match (node.left.0.as_mut(), node.right.0.as_mut()) {
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(None, None) => {
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stats.writes += 1;
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(*current).0 = None;
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},
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(None, Some(_)) => {
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stats.writes += 1;
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(*current).0 = node.right.0.take();
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},
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(Some(_), None) => {
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stats.writes += 1;
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(*current).0 = node.left.0.take();
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},
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(Some(_), Some(_)) => {
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(*current).0.as_mut().unwrap().key = {
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let mut to_return = None;
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stats.reads += 1;
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if node.right.0.is_some() {
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stats.reads += 1;
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let mut current = &mut node.right;
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stats.reads += 1;
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while current.0.as_ref().unwrap().left.0.is_some() {
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stats.writes += 1;
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current = &mut current.0.as_mut().unwrap().left;
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}
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let node = current.0.take().unwrap();
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to_return = Some(node.key);
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stats.writes += 1;
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current.0 = node.right.0;
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}
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to_return.unwrap()
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};
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},
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}
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return (true, stats);
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},
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}
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}
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}
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(false, stats)
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}
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}
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pub struct BinarySearchTree {
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pub root: BST,
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pub size: usize,
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print_capacity: usize,
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pub stats: Stats,
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}
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impl BinarySearchTree {
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pub fn new(print_capacity: usize) -> Self {
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Self {
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root: BST(None),
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size: 0,
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print_capacity,
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stats: Stats::default(),
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}
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}
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pub fn height(&self) -> usize {
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match &self.root.0 {
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Some(root) => root.height(),
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None => 0,
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}
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}
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pub fn insert(&mut self, key: u64) -> bool {
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let (ret, stats) = self.root.insert(key);
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self.stats += stats;
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ret
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}
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pub fn delete(&mut self, key: u64) -> bool {
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let (ret, stats) = self.root.delete(key);
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self.stats += stats;
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ret
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}
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pub fn reset_stats(&mut self) {
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self.stats = Stats::default();
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}
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}
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impl Display for BinarySearchTree {
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fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
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match &self.root.0 {
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Some(root) => root._print(f, 0, '-', &mut " ".repeat(self.print_capacity), &mut " ".repeat(self.print_capacity)),
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None => Ok(()),
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}
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}
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}
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@ -1,4 +1,6 @@
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use std::fmt::Display;
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mod binary_search_tree;
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pub use binary_search_tree::*;
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#[derive(Clone, Default)]
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pub struct Stats {
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@ -24,238 +26,3 @@ impl std::ops::AddAssign for Stats {
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self.writes += rhs.writes;
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}
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}
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#[derive(Clone)]
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pub struct Node {
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pub key: u64,
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pub left: Tree,
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pub right: Tree,
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}
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impl Node {
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pub fn new(key: u64) -> Self {
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Self {
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key,
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left: Tree(None),
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right: Tree(None),
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}
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}
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pub fn height(&self) -> usize {
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match (&self.left.0, &self.right.0) {
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(None, None) =>
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1,
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(None, Some(right)) =>
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1 + right.height(),
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(Some(left), None) =>
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1 + left.height(),
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(Some(left), Some(right)) =>
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1 + (left.height()).max(right.height()),
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}
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}
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// https://stackoverflow.com/a/66661638
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fn replace_nth_char_ascii(s: &mut str, idx: usize, newchar: char) {
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let s_bytes: &mut [u8] = unsafe { s.as_bytes_mut() };
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assert!(idx < s_bytes.len());
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assert!(s_bytes[idx].is_ascii());
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assert!(newchar.is_ascii());
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// we've made sure this is safe.
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s_bytes[idx] = newchar as u8;
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}
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fn _print(&self, f: &mut std::fmt::Formatter<'_>, depth: usize, prefix: char, left_trace: &mut String, right_trace: &mut String) -> std::fmt::Result {
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if let Some(left) = &self.left.0 {
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left._print(f, depth + 1, '/', left_trace, right_trace)?;
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}
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if prefix == '/' {
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Self::replace_nth_char_ascii(left_trace, depth - 1, '|');
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}
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if prefix == '\\' {
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Self::replace_nth_char_ascii(right_trace, depth - 1, ' ');
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}
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if depth == 0 {
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write!(f, "-")?;
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}
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if depth > 0 {
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write!(f, " ")?;
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}
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if depth > 0 {
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for i in 0..(depth - 1) {
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if left_trace.chars().nth(i).unwrap() == '|' || right_trace.chars().nth(i).unwrap() == '|' {
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write!(f, "| ")?;
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} else {
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write!(f, " ")?;
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}
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}
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write!(f, "{}-", prefix)?;
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}
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writeln!(f, "[{}]", self.key)?;
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Self::replace_nth_char_ascii(left_trace, depth, ' ');
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if let Some(right) = &self.right.0 {
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Self::replace_nth_char_ascii(right_trace, depth, '|');
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right._print(f, depth + 1, '\\', left_trace, right_trace)?;
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}
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Ok(())
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}
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}
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#[derive(Clone)]
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pub struct Tree(Option<Box<Node>>);
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impl Tree {
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pub fn insert(&mut self, key: u64) -> (bool, Stats) {
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let mut stats = Stats::new();
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if self.0.is_none() {
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stats.writes += 1;
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self.0 = Some(Box::new(Node::new(key)));
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return (true, stats);
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}
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let mut current = self;
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while let Some(ref mut node) = current.0 {
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stats.reads += 1;
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use std::cmp::Ordering::*;
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stats.comparisons += 1;
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match node.key.cmp(&key) {
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Greater => {
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stats.reads += 1;
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current = &mut node.left;
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},
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Less => {
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stats.reads += 1;
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current = &mut node.right;
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},
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Equal => return (false, stats),
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}
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}
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stats.writes += 1;
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current.0 = Some(Box::new(Node::new(key)));
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(true, stats)
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}
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pub fn delete(&mut self, key: u64) -> (bool, Stats) {
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let mut current: *mut Tree = self;
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let mut stats = Stats::default();
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unsafe {
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while let Some(ref mut node) = (*current).0 {
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stats.reads += 1;
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use std::cmp::Ordering::*;
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stats.comparisons += 1;
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match node.key.cmp(&key) {
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Greater => {
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stats.reads += 1;
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current = &mut node.left;
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},
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Less => {
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stats.reads += 1;
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current = &mut node.right;
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},
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Equal => {
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match (node.left.0.as_mut(), node.right.0.as_mut()) {
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(None, None) => {
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stats.writes += 1;
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(*current).0 = None;
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},
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(None, Some(_)) => {
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stats.writes += 1;
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(*current).0 = node.right.0.take();
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},
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(Some(_), None) => {
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stats.writes += 1;
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(*current).0 = node.left.0.take();
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},
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(Some(_), Some(_)) => {
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(*current).0.as_mut().unwrap().key = {
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let mut to_return = None;
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stats.reads += 1;
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if node.right.0.is_some() {
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stats.reads += 1;
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let mut current = &mut node.right;
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stats.reads += 1;
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while current.0.as_ref().unwrap().left.0.is_some() {
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stats.writes += 1;
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current = &mut current.0.as_mut().unwrap().left;
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}
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let node = current.0.take().unwrap();
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to_return = Some(node.key);
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stats.writes += 1;
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current.0 = node.right.0;
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}
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to_return.unwrap()
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};
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},
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}
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return (true, stats);
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},
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}
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}
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}
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(false, stats)
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}
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}
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pub struct BinarySearchTree {
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pub root: Tree,
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pub size: usize,
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print_capacity: usize,
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pub stats: Stats,
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}
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impl BinarySearchTree {
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pub fn new(print_capacity: usize) -> Self {
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Self {
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root: Tree(None),
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size: 0,
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print_capacity,
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stats: Stats::default(),
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}
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}
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pub fn height(&self) -> usize {
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match &self.root.0 {
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Some(root) => root.height(),
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None => 0,
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}
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}
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pub fn insert(&mut self, key: u64) -> bool {
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let (ret, stats) = self.root.insert(key);
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self.stats += stats;
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ret
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}
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pub fn delete(&mut self, key: u64) -> bool {
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let (ret, stats) = self.root.delete(key);
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self.stats += stats;
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ret
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}
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pub fn reset_stats(&mut self) {
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self.stats = Stats::default();
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}
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}
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impl Display for BinarySearchTree {
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fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
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match &self.root.0 {
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Some(root) => root._print(f, 0, '-', &mut " ".repeat(self.print_capacity), &mut " ".repeat(self.print_capacity)),
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None => Ok(()),
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}
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}
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}
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