From 31d79727b6d97f2562dd5df7be56106f31e59eb4 Mon Sep 17 00:00:00 2001
From: Greg Fitzgerald <garious@gmail.com>
Date: Wed, 14 Feb 2018 14:19:30 -0700
Subject: [PATCH] Parallelize verification

---
 .travis.yml | 17 +++++++++++++++++
 Cargo.toml  |  5 +++++
 src/lib.rs  |  3 +++
 src/tick.rs | 37 ++++++++++++++++++++++++++++++++++++-
 4 files changed, 61 insertions(+), 1 deletion(-)
 create mode 100644 .travis.yml

diff --git a/.travis.yml b/.travis.yml
new file mode 100644
index 00000000000000..a70d4ff71b8441
--- /dev/null
+++ b/.travis.yml
@@ -0,0 +1,17 @@
+language: rust
+matrix:
+  allow_failures:
+  - rust: nightly
+  include:
+  - rust: beta
+  - rust: nightly
+    env:
+    - FEATURES='unstable'
+cache: cargo
+before_script:
+- export PATH="$PATH:$HOME/.cargo/bin"
+- rustup component add rustfmt-preview
+script:
+- cargo fmt -- --write-mode=diff
+- cargo build --verbose --features "$FEATURES"
+- cargo test --verbose --features "$FEATURES"
diff --git a/Cargo.toml b/Cargo.toml
index 9d68ba06089644..3727561d4c9a72 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -3,4 +3,9 @@ name = "loomination"
 version = "0.1.0"
 authors = ["Greg Fitzgerald <garious@gmail.com>"]
 
+[features]
+unstable = []
+
 [dependencies]
+rayon = "0.9"
+itertools = "0.7.6"
diff --git a/src/lib.rs b/src/lib.rs
index e127cb341b84c0..d08f10f3b8b1ac 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1 +1,4 @@
+#![cfg_attr(feature = "unstable", feature(test))]
 pub mod tick;
+extern crate itertools;
+extern crate rayon;
diff --git a/src/tick.rs b/src/tick.rs
index f7ea7a77edf337..33127f6282323c 100644
--- a/src/tick.rs
+++ b/src/tick.rs
@@ -49,7 +49,42 @@ impl Tick {
 /// assert!(!verify_slice(&vec![Tick::new(0, 0), Tick::new(1, 0)], 0)); // lazy inductive case, bad
 /// ```
 pub fn verify_slice(ticks: &[Tick], seed: u64) -> bool {
+    use rayon::prelude::*;
     let genesis = [Tick { hash: seed, n: 0 }];
-    let mut tick_pairs = genesis.iter().chain(ticks).zip(ticks);
+    let tick_pairs = genesis.par_iter().chain(ticks).zip(ticks);
     tick_pairs.all(|(x, x1)| x1.verify(x.hash))
 }
+
+/// Verifies the hashes and ticks serially. Exists only for reference.
+pub fn verify_slice_seq(ticks: &[Tick], seed: u64) -> bool {
+    let genesis = [Tick { hash: seed, n: 0 }];
+    let tick_pairs = genesis.iter().chain(ticks).zip(ticks);
+    tick_pairs.into_iter().all(|(x, x1)| x1.verify(x.hash))
+}
+
+/// Create a vector of Ticks of length 'len' from 'seed' hash and 'hashes_per_tick'.
+pub fn create_ticks(seed: u64, hashes_per_tick: u64, len: usize) -> Vec<Tick> {
+    use itertools::unfold;
+    let mut ticks_iter = unfold(seed, |state| {
+        let tick = Tick::new(*state, hashes_per_tick);
+        *state = tick.hash;
+        return Some(tick);
+    });
+    ticks_iter.by_ref().take(len).collect()
+}
+
+#[cfg(all(feature = "unstable", test))]
+mod bench {
+    extern crate test;
+    use self::test::Bencher;
+    use tick;
+
+    #[bench]
+    fn tick_bench(bencher: &mut Bencher) {
+        let seed = 0;
+        let ticks = tick::create_ticks(seed, 100_000, 4);
+        bencher.iter(|| {
+            assert!(tick::verify_slice(&ticks, seed));
+        });
+    }
+}