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switched RadixHeapMap::push() to return a Result #12

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switched RadixHeapMap::push() to return a Result #12

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7 changes: 3 additions & 4 deletions README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -43,12 +43,11 @@ pushpop_binary time: [507.28 us 507.44 us 507.60 us]
# Example

```
extern crate radix_heap;
let mut heap = radix_heap::RadixHeapMap::new();

heap.push(7, 'a');
heap.push(2, 'b');
heap.push(9, 'c');
heap.push(7, 'a').unwrap();
heap.push(2, 'b').unwrap();
heap.push(9, 'c').unwrap();

assert!(heap.top() == None);
assert!(heap.pop() == Some((9, 'c')));
Expand Down
5 changes: 3 additions & 2 deletions benches/bench.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -174,6 +174,7 @@ impl AStarHeap for RadixHeapMap<Reverse<u32>, (Pos, u32)> {
#[inline]
fn push(&mut self, entry: AStarEntry) {
self.push(Reverse(entry.full_cost), (entry.pos, entry.cost))
.unwrap()
}

#[inline]
Expand Down Expand Up @@ -213,13 +214,13 @@ fn pushpop_radix(b: &mut Bencher) {
let mut heap = RadixHeapMap::<i32, ()>::new();

b.iter(|| {
heap.push(0, ());
heap.push(0, ()).unwrap();

for _ in 0..10000 {
let (n, _) = heap.pop().unwrap();

for i in 0..4 {
heap.push(n - i, ());
heap.push(n - i, ()).unwrap();
}
}

Expand Down
85 changes: 52 additions & 33 deletions src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -2,7 +2,12 @@
#![doc = include_str!("../README.md")]

use std::{
cmp::Reverse, default::Default, fmt, iter::FromIterator, iter::FusedIterator, num::Wrapping,
cmp::Reverse,
default::Default,
fmt::{self, Display},
iter::FromIterator,
iter::FusedIterator,
num::Wrapping,
};

type Bucket<K, V> = Vec<(K, V)>;
Expand Down Expand Up @@ -34,6 +39,19 @@ pub struct RadixHeapMap<K, V> {
initial: Bucket<K, V>,
}

/// An error type returned by [`RadixHeapMap::push()`] when given a
/// key greater than the current top key.
#[derive(Debug, Clone, Copy)]
pub struct GreaterKeyInserted;
impl Display for GreaterKeyInserted {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(
f,
"the inserted key must be lower or equal to current top key"
)
}
}

impl<K: Radix + Ord + Copy, V> RadixHeapMap<K, V> {
/// Create an empty `RadixHeapMap`
pub fn new() -> RadixHeapMap<K, V> {
Expand Down Expand Up @@ -111,22 +129,23 @@ impl<K: Radix + Ord + Copy, V> RadixHeapMap<K, V> {
.for_each(|(key, value)| buckets[key.radix_distance(&top) as usize].push((key, value)));
}

/// Pushes a new key value pair onto the heap.
///
/// Panics
/// ------
/// Panics if the key is larger than the current top key.
/// Attempts to push a new key value pair onto the heap. Fails if
/// the inserted key is greater that the current top key.
#[inline]
pub fn push(&mut self, key: K, value: V) {
let bucket = if let Some(top) = self.top {
assert!(key <= top, "Key must be lower or equal to current top key");
&mut self.buckets[key.radix_distance(&top) as usize]
pub fn push(&mut self, key: K, value: V) -> Result<(), GreaterKeyInserted> {
if let Some(top) = self.top {
if key <= top {
self.buckets[key.radix_distance(&top) as usize].push((key, value));
self.len += 1;
Ok(())
} else {
Err(GreaterKeyInserted)
}
} else {
&mut self.initial
};

bucket.push((key, value));
self.len += 1;
self.initial.push((key, value));
self.len += 1;
Ok(())
}
}

/// Remove the greatest element from the heap and returns it, or `None` if
Expand Down Expand Up @@ -211,7 +230,7 @@ impl<K: Radix + Ord + Copy, V> FromIterator<(K, V)> for RadixHeapMap<K, V> {
let mut heap = RadixHeapMap::new();

for (k, v) in iter {
heap.push(k, v);
heap.push(k, v).unwrap();
}

heap
Expand All @@ -224,7 +243,7 @@ impl<K: Radix + Ord + Copy, V> Extend<(K, V)> for RadixHeapMap<K, V> {
I: IntoIterator<Item = (K, V)>,
{
for (k, v) in iter {
self.push(k, v);
self.push(k, v).unwrap();
}
}
}
Expand All @@ -235,7 +254,7 @@ impl<'a, K: Radix + Ord + Copy + 'a, V: Copy + 'a> Extend<&'a (K, V)> for RadixH
I: IntoIterator<Item = &'a (K, V)>,
{
for &(k, v) in iter {
self.push(k, v);
self.push(k, v).unwrap();
}
}
}
Expand Down Expand Up @@ -643,17 +662,17 @@ mod tests {
#[test]
fn clear() {
let mut heap = RadixHeapMap::new();
heap.push(0u32, 'a');
heap.push(0u32, 'a').unwrap();
heap.clear();
assert!(heap.pop().is_none());
}

#[test]
fn push_pop() {
let mut heap = RadixHeapMap::new();
heap.push(0u32, 'a');
heap.push(3, 'b');
heap.push(2, 'c');
heap.push(0u32, 'a').unwrap();
heap.push(3, 'b').unwrap();
heap.push(2, 'c').unwrap();

assert!(heap.len() == 3);
assert!(!heap.is_empty());
Expand All @@ -670,9 +689,9 @@ mod tests {
#[test]
fn rev_push_pop() {
let mut heap = RadixHeapMap::new();
heap.push(Reverse(0), 'a');
heap.push(Reverse(3), 'b');
heap.push(Reverse(2), 'c');
heap.push(Reverse(0), 'a').unwrap();
heap.push(Reverse(3), 'b').unwrap();
heap.push(Reverse(2), 'c').unwrap();

assert!(heap.len() == 3);
assert!(!heap.is_empty());
Expand All @@ -690,11 +709,11 @@ mod tests {
#[should_panic]
fn push_pop_panic() {
let mut heap = RadixHeapMap::new();
heap.push(0u32, 'a');
heap.push(3, 'b');
heap.push(0u32, 'a').unwrap();
heap.push(3, 'b').unwrap();

assert!(heap.pop() == Some((3, 'b')));
heap.push(4, 'd');
heap.push(4, 'd').unwrap();
}

#[test]
Expand Down Expand Up @@ -787,8 +806,8 @@ mod tests {
#[test]
fn into_iter_inital() {
let mut heap = RadixHeapMap::new();
heap.push(1, 2);
heap.push(5, 2);
heap.push(1, 2).unwrap();
heap.push(5, 2).unwrap();

let mut vec: Vec<_> = heap.into_iter().collect();
vec.sort();
Expand All @@ -798,9 +817,9 @@ mod tests {
#[test]
fn into_iter() {
let mut heap = RadixHeapMap::new();
heap.push(1, 2);
heap.push(5, 4);
heap.push(7, 1);
heap.push(1, 2).unwrap();
heap.push(5, 4).unwrap();
heap.push(7, 1).unwrap();

assert_eq!(Some((7, 1)), heap.pop());

Expand Down