Add benchmarks

Author: dralley

Cargo.toml

@@ -62,6 +62,11 @@ name = "macrobenches"
 harness = false
 path = "benches/macrobenches.rs"
 
+[[bench]]
+name = "encoding"
+harness = false
+path = "benches/encoding.rs"
+
 [features]
 default = []
 

benches/encoding.rs

@@ -0,0 +1,57 @@
+use criterion::{criterion_group, criterion_main, BenchmarkId, Criterion, Throughput};
+use quick_xml::encoding::Utf8ValidatingReader;
+use std::io::{BufReader, Read};
+
+static SAMPLE: &[u8] = include_bytes!("../tests/documents/sample_rss.xml");
+
+/// Read the entire input through the reader using a fixed-size buffer,
+/// returning the total number of bytes read.
+fn drain_reader(reader: &mut impl Read, buf: &mut [u8]) -> usize {
+    let mut total = 0;
+    loop {
+        match reader.read(buf) {
+            Ok(0) => break,
+            Ok(n) => total += n,
+            Err(e) => panic!("unexpected error: {e}"),
+        }
+    }
+    total
+}
+
+fn bench_utf8_validation(c: &mut Criterion) {
+    let mut group = c.benchmark_group("utf8_read");
+    group.throughput(Throughput::Bytes(SAMPLE.len() as u64));
+
+    for buf_size in [64, 1024, 8192] {
+        group.bench_with_input(
+            BenchmarkId::new("BufReader_only", buf_size),
+            &buf_size,
+            |b, &buf_size| {
+                b.iter(|| {
+                    let mut reader = BufReader::new(SAMPLE);
+                    let mut buf = vec![0u8; buf_size];
+                    let n = drain_reader(&mut reader, &mut buf);
+                    assert_eq!(n, SAMPLE.len());
+                });
+            },
+        );
+
+        group.bench_with_input(
+            BenchmarkId::new("Utf8ValidatingReader", buf_size),
+            &buf_size,
+            |b, &buf_size| {
+                b.iter(|| {
+                    let mut reader = Utf8ValidatingReader::new(BufReader::new(SAMPLE));
+                    let mut buf = vec![0u8; buf_size];
+                    let n = drain_reader(&mut reader, &mut buf);
+                    assert_eq!(n, SAMPLE.len());
+                });
+            },
+        );
+    }
+
+    group.finish();
+}
+
+criterion_group!(benches, bench_utf8_validation);
+criterion_main!(benches);