Benchmark various readers for decoding

implementations/rust/benches/codec.rs

@@ -2,19 +2,37 @@ use criterion::{criterion_group, criterion_main, Criterion};
 use preserves::value::{self, decoder, encoder};
 use preserves::{de, ser};
 use std::io::Read;
+use std::io::BufReader;
+use std::io::{Seek, SeekFrom};
 
 #[path = "../tests/samples/mod.rs"]
 mod samples;
 use samples::TestCases;
 
-pub fn bench_decoder(c: &mut Criterion) {
+pub fn bench_decoder_bytes(c: &mut Criterion) {
     let mut fh = std::fs::File::open("../../tests/samples.bin").unwrap();
     let mut bs = vec![];
     fh.read_to_end(&mut bs).ok();
-    c.bench_function("decode samples.bin", |b| b.iter(
+    c.bench_function("decode samples.bin via bytes", |b| b.iter(
         || decoder::from_bytes(&bs[..]).demand_next().unwrap()));
 }
 
+pub fn bench_decoder_file(c: &mut Criterion) {
+    let mut fh = std::fs::File::open("../../tests/samples.bin").unwrap();
+    c.bench_function("decode samples.bin via file", |b| b.iter(|| {
+        fh.seek(SeekFrom::Start(0)).ok();
+        decoder::from_read(&mut fh).demand_next().unwrap()
+    }));
+}
+
+pub fn bench_decoder_buffered_file(c: &mut Criterion) {
+    let mut fh = BufReader::new(std::fs::File::open("../../tests/samples.bin").unwrap());
+    c.bench_function("decode samples.bin via buffered file", |b| b.iter(|| {
+        fh.seek(SeekFrom::Start(0)).ok();
+        decoder::from_read(&mut fh).demand_next().unwrap()
+    }));
+}
+
 pub fn bench_encoder(c: &mut Criterion) {
     let mut fh = std::fs::File::open("../../tests/samples.bin").unwrap();
     let v = decoder::from_read(&mut fh).demand_next().unwrap();
@@ -61,7 +79,9 @@ pub fn bench_ser_encoder(c: &mut Criterion) {
     }));
 }
 
-criterion_group!(codec, bench_decoder, bench_encoder);
+criterion_group!(codec,
+                 bench_decoder_bytes, bench_decoder_file, bench_decoder_buffered_file,
+                 bench_encoder);
 criterion_group!(serde, bench_de, bench_ser);
 criterion_group!(codec_then_serde, bench_decoder_de, bench_ser_encoder);
 criterion_main!(codec, serde, codec_then_serde);