Reorganize hasher and add hasher benchmark

Cargo.toml

@@ -39,4 +39,8 @@ harness = false
 
 [[bench]]
 name = "ilp"
+harness = false
+
+[[bench]]
+name = "hashset"
 harness = false

benches/hashset.rs

@@ -0,0 +1,47 @@
+use criterion::{criterion_group, criterion_main, Criterion};
+use fnv::FnvHashSet;
+use gxhash::*;
+use twox_hash::xxh3;
+use std::collections::HashSet;
+use std::hash::BuildHasherDefault;
+
+fn hashmap_insertion(c: &mut Criterion) {
+
+    // Long keys
+    benchmark_for_string(c, "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.");
+
+    // Medium keys
+    benchmark_for_string(c, "https://github.com/ogxd/gxhash");
+
+    // Short keys
+    benchmark_for_string(c, "gxhash");
+}
+
+fn benchmark_for_string(c: &mut Criterion, string: &str) {
+    let mut group = c.benchmark_group(format!("HashSet<&str[{}]>", string.len()));
+
+    let mut set = HashSet::new();
+    group.bench_function("Default Hasher", |b| {
+        b.iter(|| set.insert(string))
+    });
+
+    let mut set = GxHashSet::default();
+    group.bench_function("GxHash", |b| {
+        b.iter(|| set.insert(string))
+    });
+
+    let mut set = HashSet::<&str, BuildHasherDefault<xxh3::Hash64>>::default();
+    group.bench_function("XxHash", |b| {
+        b.iter(|| set.insert(string))
+    });
+
+    let mut set = FnvHashSet::default();
+    group.bench_function("FNV-1a", |b| {
+        b.iter(|| set.insert(string))
+    });
+
+    group.finish();
+}
+
+criterion_group!(benches, hashmap_insertion);
+criterion_main!(benches);

src/gxhash/mod.rs

@@ -1,4 +1,4 @@
-mod platform;
+pub(crate) mod platform;
 
 use platform::*;
 
@@ -38,7 +38,7 @@ const RANGE_3_BEGIN: isize  = RANGE_2_BEGIN + 1;
 const RANGE_3_END: isize    = VECTOR_SIZE * 4;
 
 #[inline(always)]
-unsafe fn gxhash(input: &[u8], seed: State) -> State {
+pub(crate) unsafe fn gxhash(input: &[u8], seed: State) -> State {
 
     let len: isize = input.len() as isize;
     let mut ptr = input.as_ptr() as *const State;
@@ -114,74 +114,13 @@ unsafe fn gxhash_process_1(mut ptr: *const State, hash_vector: State, remaining_
     (hash_vector, remaining_bytes, ptr)
 }
 
-use std::hash::{Hasher, BuildHasherDefault};
-use std::collections::{HashMap, HashSet};
-
-pub struct GxHasher(State);
-
-impl Default for GxHasher {
-    #[inline]
-    fn default() -> GxHasher {
-        GxHasher(unsafe { create_empty() })
-    }
-}
-
-impl GxHasher {
-    #[inline]
-    pub fn with_seed(seed: i32) -> GxHasher {
-        // Use gxhash64 to generate an initial state from a seed
-        GxHasher(unsafe { gxhash(&[], create_seed(seed)) })
-    }
-}
-
-impl Hasher for GxHasher {
-    #[inline]
-    fn finish(&self) -> u64 {
-        unsafe {
-            let p = &self.0 as *const State as *const u64;
-            *p
-        }
-    }
-
-    #[inline]
-    fn write(&mut self, bytes: &[u8]) {
-        self.0 = unsafe { gxhash(bytes, self.0) };
-    }
-}
-
-/// A builder for default FNV hashers.
-pub type GxBuildHasher = BuildHasherDefault<GxHasher>;
-
-/// A `HashMap` using a default GxHash hasher.
-//#[cfg(feature = "std")]
-pub type GxHashMap<K, V> = HashMap<K, V, GxBuildHasher>;
-
-/// A `HashSet` using a default GxHash hasher.
-//#[cfg(feature = "std")]
-pub type GxHashSet<T> = HashSet<T, GxBuildHasher>;
-
 #[cfg(test)]
 mod tests {
 
     use super::*;
-    use ahash::HashSetExt;
     use rand::Rng;
     use rstest::rstest;
 
-    #[test]
-    fn hasher_works() {
-        let mut hashset = GxHashSet::new();
-        assert!(hashset.insert(1234));
-        assert!(!hashset.insert(1234));
-        assert!(hashset.insert(42));
-
-        let mut hashset = GxHashSet::new();
-        assert!(hashset.insert("hello"));
-        assert!(hashset.insert("world"));
-        assert!(!hashset.insert("hello"));
-        assert!(hashset.insert("bye"));
-    }
-
     #[rstest]
     #[case(4)]
     #[case(16)]

src/hasher.rs

@@ -0,0 +1,68 @@
+use std::hash::{Hasher, BuildHasherDefault};
+use std::collections::{HashMap, HashSet};
+use crate::gxhash::*;
+use crate::gxhash::platform::*;
+
+pub struct GxHasher(State);
+
+impl Default for GxHasher {
+    #[inline]
+    fn default() -> GxHasher {
+        GxHasher(unsafe { create_empty() })
+    }
+}
+
+impl GxHasher {
+    #[inline]
+    pub fn with_seed(seed: i32) -> GxHasher {
+        // Use gxhash64 to generate an initial state from a seed
+        GxHasher(unsafe { gxhash(&[], create_seed(seed)) })
+    }
+}
+
+impl Hasher for GxHasher {
+    #[inline]
+    fn finish(&self) -> u64 {
+        unsafe {
+            let p = &self.0 as *const State as *const u64;
+            *p
+        }
+    }
+
+    #[inline]
+    fn write(&mut self, bytes: &[u8]) {
+        // Improvement: only compress at this stage and finalize in finish
+        self.0 = unsafe { gxhash(bytes, self.0) };
+    }
+}
+
+/// A builder for default FNV hashers.
+pub type GxBuildHasher = BuildHasherDefault<GxHasher>;
+
+/// A `HashMap` using a default GxHash hasher.
+//#[cfg(feature = "std")]
+pub type GxHashMap<K, V> = HashMap<K, V, GxBuildHasher>;
+
+/// A `HashSet` using a default GxHash hasher.
+//#[cfg(feature = "std")]
+pub type GxHashSet<T> = HashSet<T, GxBuildHasher>;
+
+#[cfg(test)]
+mod tests {
+
+    use super::*;
+
+    #[test]
+    fn hasher_works() {
+        let mut hashset = GxHashSet::default();
+        assert!(hashset.insert(1234));
+        assert!(!hashset.insert(1234));
+        assert!(hashset.insert(42));
+
+        let mut hashset = GxHashSet::default();
+        assert!(hashset.insert("hello"));
+        assert!(hashset.insert("world"));
+        assert!(!hashset.insert("hello"));
+        assert!(hashset.insert("bye"));
+    }
+}

src/lib.rs

@@ -2,5 +2,7 @@
 #![feature(stdsimd)]
 
 mod gxhash;
+mod hasher;
 
-pub use gxhash::*;
+pub use gxhash::*;
+pub use hasher::*;