Add a benchmark covering Reader.next_frame_info.

Cargo.toml

@@ -48,13 +48,18 @@ name = "decoder"
 harness = false
 
 [[bench]]
-path = "benches/unfilter.rs"
-name = "unfilter"
+path = "benches/expand_paletted.rs"
+name = "expand_paletted"
 harness = false
 required-features = ["benchmarks"]
 
 [[bench]]
-path = "benches/expand_paletted.rs"
-name = "expand_paletted"
+path = "benches/next_frame_info.rs"
+name = "next_frame_info"
+harness = false
+
+[[bench]]
+path = "benches/unfilter.rs"
+name = "unfilter"
 harness = false
 required-features = ["benchmarks"]

benches/next_frame_info.rs

@@ -0,0 +1,43 @@
+use std::fs;
+use std::path::Path;
+
+use criterion::{
+    criterion_group, criterion_main, measurement::WallTime, BenchmarkGroup, Criterion,
+};
+use png::Decoder;
+
+criterion_group! {benches, load_all}
+criterion_main!(benches);
+
+fn load_all(c: &mut Criterion) {
+    let mut g = c.benchmark_group("next_frame_info");
+    bench_file(&mut g, Path::new("tests/animated/basic_f20.png"), 18, 35);
+}
+
+fn bench_file(
+    g: &mut BenchmarkGroup<WallTime>,
+    png_path: &Path,
+    number_of_frames_to_skip: usize,
+    expected_fctl_sequence_number: u32,
+) {
+    let data = fs::read(png_path).unwrap();
+    let name = format!("{}: {} skips", png_path.display(), number_of_frames_to_skip);
+    g.bench_with_input(&name, data.as_slice(), |b, data| {
+        b.iter(|| {
+            let decoder = Decoder::new(data);
+            let mut reader = decoder.read_info().unwrap();
+            for _ in 0..number_of_frames_to_skip {
+                reader.next_frame_info().unwrap();
+            }
+            assert_eq!(
+                reader
+                    .info()
+                    .frame_control
+                    .as_ref()
+                    .unwrap()
+                    .sequence_number,
+                expected_fctl_sequence_number,
+            );
+        })
+    });
+}