Merge pull request #4 from alecmocatta/fixes

fixes, stricter integer casts

src/count_min.rs

@@ -20,9 +20,10 @@
 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 // SOFTWARE.
 
+use super::f64_to_usize;
 use serde::{de::Deserialize, ser::Serialize};
 use std::{
-	borrow::Borrow, cmp::max, fmt, hash::{Hash, Hasher}, marker::PhantomData, ops
+	borrow::Borrow, cmp::max, convert::TryFrom, fmt, hash::{Hash, Hasher}, marker::PhantomData, ops
 };
 use traits::{Intersect, IntersectPlusUnionIsPlus, New, UnionAssign};
 use twox_hash::XxHash;
@@ -165,7 +166,7 @@ where
 
 	fn optimal_width(tolerance: f64) -> usize {
 		let e = tolerance;
-		let width = (2.0 / e).round() as usize;
+		let width = f64_to_usize((2.0 / e).round());
 		max(2, width)
 			.checked_next_power_of_two()
 			.expect("Width would be way too large")
@@ -178,27 +179,19 @@ where
 	}
 
 	fn optimal_k_num(probability: f64) -> usize {
-		max(1, ((1.0 - probability).ln() / 0.5_f64.ln()) as usize)
+		max(
+			1,
+			f64_to_usize(((1.0 - probability).ln() / 0.5_f64.ln()).floor()),
+		)
 	}
 
 	fn offsets<Q: ?Sized>(&self, key: &Q) -> impl Iterator<Item = usize>
 	where
 		Q: Hash,
 		K: Borrow<Q>,
 	{
-		// if k_i < 2 {
-		//     let sip = &mut self.hashers[k_i as usize].clone();
-		//     key.hash(sip);
-		//     let hash = sip.finish();
-		//     hashes[k_i as usize] = hash;
-		//     hash as usize & self.mask
-		// } else {
-		//     hashes[0]
-		//         .wrapping_add((k_i as u64).wrapping_mul(hashes[1]) %
-		//                       0xffffffffffffffc5) as usize & self.mask
-		// }
 		let mask = self.mask;
-		hashes(key).map(move |hash| hash as usize & mask)
+		hashes(key).map(move |hash| usize::try_from(hash & u64::try_from(mask).unwrap()).unwrap())
 	}
 }
 

src/distinct.rs

@@ -44,16 +44,83 @@
 // https://spark.apache.org/docs/latest/api/scala/index.html#org.apache.spark.rdd.RDD countApproxDistinct
 // is_x86_feature_detected ?
 
+use super::{f64_to_u8, u64_to_f64, usize_to_f64};
 use packed_simd::{self, Cast, FromBits, IntoBits};
 use std::{
-	cmp::{self, Ordering}, convert::identity, fmt, hash::{Hash, Hasher}, marker::PhantomData, ops::{self, Range}
+	cmp::{self, Ordering}, convert::{identity, TryFrom}, fmt, hash::{Hash, Hasher}, marker::PhantomData, ops::{self, Range}
 };
 use traits::{Intersect, IntersectPlusUnionIsPlus, New, UnionAssign};
 use twox_hash::XxHash;
 
 mod consts;
 use self::consts::*;
 
+/// Like [`HyperLogLog`] but implements `Ord` and `Eq` by using the estimate of the cardinality.
+#[derive(Serialize, Deserialize)]
+#[serde(bound = "")]
+pub struct HyperLogLogMagnitude<V>(HyperLogLog<V>);
+impl<V: Hash> Ord for HyperLogLogMagnitude<V> {
+	#[inline(always)]
+	fn cmp(&self, other: &Self) -> Ordering {
+		self.0.len().partial_cmp(&other.0.len()).unwrap()
+	}
+}
+impl<V: Hash> PartialOrd for HyperLogLogMagnitude<V> {
+	#[inline(always)]
+	fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
+		self.0.len().partial_cmp(&other.0.len())
+	}
+}
+impl<V: Hash> PartialEq for HyperLogLogMagnitude<V> {
+	#[inline(always)]
+	fn eq(&self, other: &Self) -> bool {
+		self.0.len().eq(&other.0.len())
+	}
+}
+impl<V: Hash> Eq for HyperLogLogMagnitude<V> {}
+impl<V: Hash> Clone for HyperLogLogMagnitude<V> {
+	fn clone(&self) -> Self {
+		HyperLogLogMagnitude(self.0.clone())
+	}
+}
+impl<V: Hash> New for HyperLogLogMagnitude<V> {
+	type Config = f64;
+	fn new(config: &Self::Config) -> Self {
+		HyperLogLogMagnitude(New::new(config))
+	}
+}
+impl<V: Hash> Intersect for HyperLogLogMagnitude<V> {
+	fn intersect<'a>(iter: impl Iterator<Item = &'a Self>) -> Option<Self>
+	where
+		Self: Sized + 'a,
+	{
+		Intersect::intersect(iter.map(|x| &x.0)).map(HyperLogLogMagnitude)
+	}
+}
+impl<'a, V: Hash> UnionAssign<&'a HyperLogLogMagnitude<V>> for HyperLogLogMagnitude<V> {
+	fn union_assign(&mut self, rhs: &'a Self) {
+		self.0.union_assign(&rhs.0)
+	}
+}
+impl<'a, V: Hash> ops::AddAssign<&'a V> for HyperLogLogMagnitude<V> {
+	fn add_assign(&mut self, rhs: &'a V) {
+		self.0.add_assign(rhs)
+	}
+}
+impl<'a, V: Hash> ops::AddAssign<&'a Self> for HyperLogLogMagnitude<V> {
+	fn add_assign(&mut self, rhs: &'a Self) {
+		self.0.add_assign(&rhs.0)
+	}
+}
+impl<V: Hash> fmt::Debug for HyperLogLogMagnitude<V> {
+	fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+		self.0.fmt(fmt)
+	}
+}
+impl<V> IntersectPlusUnionIsPlus for HyperLogLogMagnitude<V> {
+	const VAL: bool = <HyperLogLog<V> as IntersectPlusUnionIsPlus>::VAL;
+}
+
 /// An implementation of the [HyperLogLog](https://en.wikipedia.org/wiki/HyperLogLog) data structure with *bias correction*.
 ///
 /// See [*HyperLogLog: the analysis of a near-optimal cardinality estimation algorithm*](http://algo.inria.fr/flajolet/Publications/FlFuGaMe07.pdf) and [*HyperLogLog in Practice: Algorithmic Engineering of a State of The Art Cardinality Estimation Algorithm*](https://ai.google/research/pubs/pub40671) for background on HyperLogLog with bias correction.
@@ -75,13 +142,13 @@ where
 	/// Create an empty `HyperLogLog` data structure with the specified error tolerance.
 	pub fn new(error_rate: f64) -> Self {
 		assert!(0.0 < error_rate && error_rate < 1.0);
-		let p = (f64::log2(1.04 / error_rate) * 2.0).ceil() as u8;
+		let p = f64_to_u8((f64::log2(1.04 / error_rate) * 2.0).ceil());
 		assert!(0 < p && p < 64);
 		let alpha = Self::get_alpha(p);
 		Self {
 			alpha,
 			zero: 1 << p,
-			sum: (1 << p) as f64,
+			sum: f64::from(1 << p),
 			p,
 			m: vec![0; 1 << p].into_boxed_slice(),
 			marker: PhantomData,
@@ -93,7 +160,7 @@ where
 		Self {
 			alpha: hll.alpha,
 			zero: hll.m.len(),
-			sum: hll.m.len() as f64,
+			sum: usize_to_f64(hll.m.len()),
 			p: hll.p,
 			m: vec![0; hll.m.len()].into_boxed_slice(),
 			marker: PhantomData,
@@ -109,14 +176,14 @@ where
 		let j = x & (self.m.len() as u64 - 1);
 		let w = x >> self.p;
 		let rho = Self::get_rho(w, 64 - self.p);
-		let mjr = &mut self.m[j as usize];
+		let mjr = &mut self.m[usize::try_from(j).unwrap()];
 		let old = *mjr;
 		let new = cmp::max(old, rho);
 		self.zero -= if old == 0 { 1 } else { 0 };
 
 		// see pow_bithack()
-		self.sum -= f64::from_bits(u64::max_value().wrapping_sub(old as u64) << 54 >> 2)
-			- f64::from_bits(u64::max_value().wrapping_sub(new as u64) << 54 >> 2);
+		self.sum -= f64::from_bits(u64::max_value().wrapping_sub(u64::from(old)) << 54 >> 2)
+			- f64::from_bits(u64::max_value().wrapping_sub(u64::from(new)) << 54 >> 2);
 
 		*mjr = new;
 	}
@@ -125,7 +192,8 @@ where
 	pub fn len(&self) -> f64 {
 		let v = self.zero;
 		if v > 0 {
-			let h = self.m.len() as f64 * (self.m.len() as f64 / v as f64).ln();
+			let h =
+				usize_to_f64(self.m.len()) * (usize_to_f64(self.m.len()) / usize_to_f64(v)).ln();
 			if h <= Self::get_threshold(self.p - 4) {
 				return h;
 			}
@@ -170,8 +238,8 @@ where
 				}
 			}
 		}
-		self.zero = zero.wrapping_sum() as usize;
-		self.sum = sum.sum() as f64;
+		self.zero = usize::try_from(zero.wrapping_sum()).unwrap();
+		self.sum = f64::from(sum.sum());
 		// https://github.com/AdamNiederer/faster/issues/37
 		// (src.m.simd_iter(faster::u8s(0)),self.m.simd_iter_mut(faster::u8s(0))).zip()
 	}
@@ -208,14 +276,14 @@ where
 				}
 			}
 		}
-		self.zero = zero.wrapping_sum() as usize;
-		self.sum = sum.sum() as f64;
+		self.zero = usize::try_from(zero.wrapping_sum()).unwrap();
+		self.sum = f64::from(sum.sum());
 	}
 
 	/// Clears the `HyperLogLog` data structure, as if it was new.
 	pub fn clear(&mut self) {
 		self.zero = self.m.len();
-		self.sum = self.m.len() as f64;
+		self.sum = usize_to_f64(self.m.len());
 		self.m.iter_mut().for_each(|x| {
 			*x = 0;
 		});
@@ -231,12 +299,12 @@ where
 			4 => 0.673,
 			5 => 0.697,
 			6 => 0.709,
-			_ => 0.7213 / (1.0 + 1.079 / (1_u64 << p) as f64),
+			_ => 0.7213 / (1.0 + 1.079 / u64_to_f64(1_u64 << p)),
 		}
 	}
 
 	fn get_rho(w: u64, max_width: u8) -> u8 {
-		let rho = max_width - (64 - w.leading_zeros() as u8) + 1;
+		let rho = max_width - (64 - u8::try_from(w.leading_zeros()).unwrap()) + 1;
 		assert!(0 < rho && rho < 65);
 		rho
 	}
@@ -245,7 +313,7 @@ where
 		let bias_vector = BIAS_DATA[(p - 4) as usize];
 		let neighbors = Self::get_nearest_neighbors(e, RAW_ESTIMATE_DATA[(p - 4) as usize]);
 		assert_eq!(neighbors.len(), 6);
-		bias_vector[neighbors].into_iter().sum::<f64>() / 6.0_f64
+		bias_vector[neighbors].iter().sum::<f64>() / 6.0_f64
 	}
 
 	fn get_nearest_neighbors(e: f64, estimate_vector: &[f64]) -> Range<usize> {
@@ -275,8 +343,8 @@ where
 	}
 
 	fn ep(&self) -> f64 {
-		let e = self.alpha * (self.m.len() * self.m.len()) as f64 / self.sum;
-		if e <= (5 * self.m.len()) as f64 {
+		let e = self.alpha * usize_to_f64(self.m.len() * self.m.len()) / self.sum;
+		if e <= usize_to_f64(5 * self.m.len()) {
 			e - Self::estimate_bias(e, self.p)
 		} else {
 			e
@@ -346,6 +414,14 @@ where
 		self.push(rhs)
 	}
 }
+impl<'a, V: ?Sized> ops::AddAssign<&'a Self> for HyperLogLog<V>
+where
+	V: Hash,
+{
+	fn add_assign(&mut self, rhs: &'a Self) {
+		self.union(rhs)
+	}
+}
 impl<V: ?Sized> IntersectPlusUnionIsPlus for HyperLogLog<V> {
 	const VAL: bool = true;
 }
@@ -444,25 +520,25 @@ impl Sad<packed_simd::u8x8> {
 	#[inline(always)]
 	unsafe fn sad(a: packed_simd::u8x8, b: packed_simd::u8x8) -> u64 {
 		assert_eq!(b, packed_simd::u8x8::splat(0));
-		(0..8).map(|i| a.extract(i) as u64).sum()
+		(0..8).map(|i| u64::from(a.extract(i))).sum()
 	}
 }
 
 #[cfg(test)]
 mod test {
-	use super::HyperLogLog;
+	use super::{super::f64_to_usize, HyperLogLog};
 	use std::f64;
 
 	#[test]
 	fn pow_bithack() {
 		// build the float from x, manipulating it to be the mantissa we want.
 		// no portability issues in theory https://doc.rust-lang.org/stable/std/primitive.f64.html#method.from_bits
 		for x in 0_u8..65 {
-			let a = 2.0_f64.powi(-(x as i32));
-			let b = f64::from_bits(u64::max_value().wrapping_sub(x as u64) << 54 >> 2);
-			let c = f32::from_bits(u32::max_value().wrapping_sub(x as u32) << 25 >> 2);
+			let a = 2.0_f64.powi(-(i32::from(x)));
+			let b = f64::from_bits(u64::max_value().wrapping_sub(u64::from(x)) << 54 >> 2);
+			let c = f32::from_bits(u32::max_value().wrapping_sub(u32::from(x)) << 25 >> 2);
 			assert_eq!(a, b);
-			assert_eq!(a, c as f64);
+			assert_eq!(a, f64::from(c));
 		}
 	}
 
@@ -505,7 +581,7 @@ mod test {
 		let actual = 100_000.0;
 		let p = 0.05;
 		let mut hll = HyperLogLog::new(p);
-		for i in 0..actual as usize {
+		for i in 0..f64_to_usize(actual) {
 			hll.push(&i);
 		}
 

src/lib.rs

@@ -22,7 +22,7 @@
 //! As these implementations are often in hot code paths, unsafe is used, albeit only when necessary to a) achieve the asymptotically optimal algorithm or b) mitigate an observed bottleneck.
 
 #![doc(html_root_url = "https://docs.rs/streaming_algorithms/0.1.0")]
-#![feature(nll, specialization, convert_id)]
+#![feature(nll, specialization, convert_id, try_trait, try_from)]
 #![warn(
 	missing_copy_implementations,
 	missing_debug_implementations,
@@ -43,10 +43,7 @@
 	clippy::if_not_else,
 	clippy::op_ref,
 	clippy::needless_pass_by_value,
-	clippy::cast_possible_truncation,
-	clippy::cast_sign_loss,
-	clippy::cast_precision_loss,
-	clippy::cast_lossless,
+	clippy::suspicious_op_assign_impl,
 	clippy::float_cmp
 )]
 
@@ -70,3 +67,35 @@ pub use distinct::*;
 pub use sample::*;
 pub use top::*;
 pub use traits::*;
+
+// TODO: replace all instances of the following with a.try_into().unwrap() if/when that exists https://github.com/rust-lang/rust/pull/47857
+#[allow(
+	clippy::cast_possible_truncation,
+	clippy::cast_sign_loss,
+	clippy::cast_precision_loss
+)]
+fn f64_to_usize(a: f64) -> usize {
+	assert!(a.is_sign_positive() && a <= usize::max_value() as f64 && a.fract() == 0.0);
+	a as usize
+}
+
+#[allow(
+	clippy::cast_possible_truncation,
+	clippy::cast_sign_loss,
+	clippy::cast_precision_loss
+)]
+fn f64_to_u8(a: f64) -> u8 {
+	assert!(a.is_sign_positive() && a <= f64::from(u8::max_value()) && a.fract() == 0.0);
+	a as u8
+}
+
+#[allow(clippy::cast_precision_loss)]
+fn usize_to_f64(a: usize) -> f64 {
+	assert!(a as u64 <= 1_u64 << 53);
+	a as f64
+}
+#[allow(clippy::cast_precision_loss)]
+fn u64_to_f64(a: u64) -> f64 {
+	assert!(a <= 1_u64 << 53);
+	a as f64
+}

src/linked_list.rs

@@ -145,21 +145,29 @@ impl<T> LinkedList<T> {
 		LinkedListIndex(idx, marker::PhantomData)
 	}
 	pub fn pop_back(&mut self) -> T {
+		assert_ne!(self.len, 0);
 		let idx = self.tail;
 		let ret = self.vec[idx].2.take().unwrap();
 		self.tail = self.vec[idx].0;
-		self.vec[self.tail].1 = usize::max_value();
+		if self.tail != usize::max_value() {
+			self.vec[self.tail].1 = usize::max_value();
+		} else {
+			self.head = usize::max_value();
+		}
 		self.free(idx);
 		self.len -= 1;
 		self.assert();
 		ret
 	}
 	pub fn pop_front(&mut self) -> T {
+		assert_ne!(self.len, 0);
 		let idx = self.head;
 		let ret = self.vec[idx].2.take().unwrap();
 		self.head = self.vec[idx].1;
 		if self.head != usize::max_value() {
 			self.vec[self.head].0 = usize::max_value();
+		} else {
+			self.tail = usize::max_value();
 		}
 		self.free(idx);
 		self.len -= 1;