From 24afca5d322950eb7154fd4bcea56da216321c2f Mon Sep 17 00:00:00 2001
From: Tony Garnock-Jones <tonyg@leastfixedpoint.com>
Date: Wed, 17 Jun 2020 11:01:31 +0200
Subject: [PATCH] Avoid expensive setup

---
 implementations/rust/benches/codec.rs | 61 +++++++++++++++------------
 1 file changed, 33 insertions(+), 28 deletions(-)

diff --git a/implementations/rust/benches/codec.rs b/implementations/rust/benches/codec.rs
index a011285..0606ef9 100644
--- a/implementations/rust/benches/codec.rs
+++ b/implementations/rust/benches/codec.rs
@@ -80,41 +80,46 @@ pub fn bench_ser_encoder(c: &mut Criterion) {
 }
 
 pub fn large_testdata_decoder_with_ann(c: &mut Criterion) {
-    let mut fh = std::fs::File::open("benches/testdata.bin").unwrap();
-    let mut bs = vec![];
-    fh.read_to_end(&mut bs).ok();
-    c.bench_function("decode testdata.bin with annotations", |b| b.iter(|| {
-        let mut r = reader::from_bytes(&bs[..]);
-        while let Some(_) = r.next(true).unwrap() {}
-    }));
+    c.bench_function("decode testdata.bin with annotations", |b| {
+        let mut fh = std::fs::File::open("benches/testdata.bin").unwrap();
+        let mut bs = vec![];
+        fh.read_to_end(&mut bs).ok();
+        b.iter(|| {
+            let mut r = reader::from_bytes(&bs[..]);
+            while let Some(_) = r.next(true).unwrap() {}
+        })
+    });
 }
 
 pub fn large_testdata_decoder_without_ann(c: &mut Criterion) {
-    let mut fh = std::fs::File::open("benches/testdata.bin").unwrap();
-    let mut bs = vec![];
-    fh.read_to_end(&mut bs).ok();
-    c.bench_function("decode testdata.bin without annotations", |b| b.iter(|| {
-        let mut r = reader::from_bytes(&bs[..]);
-        while let Some(_) = r.next(false).unwrap() {}
-    }));
+    c.bench_function("decode testdata.bin without annotations", |b| {
+        let mut fh = std::fs::File::open("benches/testdata.bin").unwrap();
+        let mut bs = vec![];
+        fh.read_to_end(&mut bs).ok();
+        b.iter(|| {
+            let mut r = reader::from_bytes(&bs[..]);
+            while let Some(_) = r.next(false).unwrap() {}
+        })
+    });
 }
 
 pub fn large_testdata_encoder(c: &mut Criterion) {
-    let mut fh = std::fs::File::open("benches/testdata.bin").unwrap();
-    let mut vs = vec![];
-    let mut r = reader::from_read(&mut fh);
-    while let Some(v) = r.next(true).unwrap() {
-        vs.push(v);
-    }
-
-    c.bench_function("encode testdata.bin", |b| b.iter_with_large_drop(|| {
-        let mut bs = vec![];
-        let mut e = encoder::Encoder::new(&mut bs);
-        for v in &vs {
-            e.write(&v).unwrap();
+    c.bench_function("encode testdata.bin", |b| {
+        let mut fh = BufReader::new(std::fs::File::open("benches/testdata.bin").unwrap());
+        let mut vs = vec![];
+        let mut r = reader::from_read(&mut fh);
+        while let Some(v) = r.next(true).unwrap() {
+            vs.push(v);
         }
-        bs
-    }));
+        b.iter_with_large_drop(|| {
+            let mut bs = vec![];
+            let mut e = encoder::Encoder::new(&mut bs);
+            for v in &vs {
+                e.write(&v).unwrap();
+            }
+            bs
+        })
+    });
 }
 
 criterion_group!(codec,