From 05614782d11d53b9c8022c894eb5728fa8f1f591 Mon Sep 17 00:00:00 2001
From: Simon Gardling <titaniumtown@gmail.com>
Date: Wed, 4 May 2022 11:11:38 -0400
Subject: [PATCH] performance improvements

---
 benchmarks/src/lib.rs      | 15 ++++++---------
 parsing/src/lib.rs         |  1 +
 parsing/src/suggestions.rs | 16 ++++++++++++----
 3 files changed, 19 insertions(+), 13 deletions(-)

diff --git a/benchmarks/src/lib.rs b/benchmarks/src/lib.rs
index 4a40a0e..d091d3c 100644
--- a/benchmarks/src/lib.rs
+++ b/benchmarks/src/lib.rs
@@ -55,6 +55,7 @@ fn custom_criterion() -> Criterion {
 	Criterion::default()
 		// .with_profiler(FlamegraphProfiler::new(100))
 		.warm_up_time(Duration::from_millis(250))
+		.sample_size(1000)
 }
 
 #[criterion(custom_criterion())]
@@ -79,15 +80,11 @@ fn split_function_bench(c: &mut Criterion) {
 
 	let mut group = c.benchmark_group("split_function");
 	for entry in data_chars {
-		group.bench_with_input(
-			BenchmarkId::new("split_function", entry.iter().collect::<String>()),
-			&entry,
-			|b, i| {
-				b.iter(|| {
-					split_function_chars(i);
-				})
-			},
-		);
+		group.bench_function(entry.iter().collect::<String>(), |b| {
+			b.iter(|| {
+				split_function_chars(&entry);
+			})
+		});
 	}
 	group.finish();
 }
diff --git a/parsing/src/lib.rs b/parsing/src/lib.rs
index 47a9fd0..1b73b11 100644
--- a/parsing/src/lib.rs
+++ b/parsing/src/lib.rs
@@ -1,4 +1,5 @@
 #![feature(const_trait_impl)]
+#![feature(core_intrinsics)]
 
 pub mod parsing;
 pub mod suggestions;
diff --git a/parsing/src/suggestions.rs b/parsing/src/suggestions.rs
index c542d13..1b99ae9 100644
--- a/parsing/src/suggestions.rs
+++ b/parsing/src/suggestions.rs
@@ -1,3 +1,5 @@
+use std::intrinsics::assume;
+
 use crate::parsing::is_variable;
 
 pub const HINT_EMPTY: Hint = Hint::Single("x^2");
@@ -35,7 +37,7 @@ pub fn split_function_chars(chars: &[char]) -> Vec<String> {
 	}
 
 	// Resulting split-up data
-	let mut data: Vec<String> = Vec::with_capacity(chars.len());
+	let mut data: Vec<Vec<&char>> = Vec::with_capacity(chars.len());
 
 	// Buffer used to store data ready to be appended
 	let mut buffer: Vec<&char> = Vec::with_capacity(chars.len());
@@ -156,7 +158,7 @@ pub fn split_function_chars(chars: &[char]) -> Vec<String> {
 
 		// Append split
 		if do_split {
-			data.push(buffer.iter().cloned().collect::<String>());
+			data.push(buffer.clone());
 			buffer.clear();
 		}
 
@@ -169,10 +171,16 @@ pub fn split_function_chars(chars: &[char]) -> Vec<String> {
 
 	// If there is still data in the buffer, append it
 	if !buffer.is_empty() {
-		data.push(buffer.iter().cloned().collect::<String>());
+		data.push(buffer);
 	}
 
-	data
+	unsafe {
+		assume(!data.is_empty());
+	}
+
+	data.iter()
+		.map(|e| e.iter().cloned().collect::<String>())
+		.collect()
 }
 
 /// Generate a hint based on the input `input`, returns an `Option<String>`