bench: add deflate_many_small_files bench for #633

Cargo.toml

@@ -68,6 +68,7 @@ wasm-bindgen-test = "^0.3.56"
 
 [dev-dependencies]
 bencher = "0.1"
+criterion = "0.5"
 getrandom = { version = "0.4", default-features = false }
 walkdir = "2.5"
 time = { version = "^0.3.47", features = ["formatting", "macros"] }
@@ -134,3 +135,7 @@ harness = false
 [[bench]]
 name = "merge_archive"
 harness = false
+
+[[bench]]
+name = "deflate_alloc"
+harness = false

benches/deflate_alloc.rs

@@ -0,0 +1,41 @@
+use criterion::{criterion_group, criterion_main, Criterion, BenchmarkId, Throughput};
+use std::io::{Cursor, Write};
+use zip::write::SimpleFileOptions;
+use zip::ZipWriter;
+use zip::CompressionMethod;
+
+fn bench_many_small_files(c: &mut Criterion) {
+    let mut group = c.benchmark_group("deflate_many_small");
+    for n in [10, 100, 500].iter() {
+        let data = vec![b'x'; 1024];
+        group.throughput(Throughput::Bytes((*n as u64)*1024));
+        group.bench_with_input(BenchmarkId::new("deflate", n), n, |b, &n| {
+            b.iter(|| {
+                let buf = Cursor::new(Vec::new());
+                let mut zip = ZipWriter::new(buf);
+                let opts = SimpleFileOptions::default().compression_method(CompressionMethod::DEFLATE);
+                for i in 0..n {
+                    zip.start_file(format!("file_{:04}.txt", i), opts).unwrap();
+                    zip.write_all(&data).unwrap();
+                }
+                zip.finish().unwrap()
+            })
+        });
+        group.bench_with_input(BenchmarkId::new("stored", n), n, |b, &n| {
+            b.iter(|| {
+                let buf = Cursor::new(Vec::new());
+                let mut zip = ZipWriter::new(buf);
+                let opts = SimpleFileOptions::default().compression_method(CompressionMethod::Stored);
+                for i in 0..n {
+                    zip.start_file(format!("file_{:04}.txt", i), opts).unwrap();
+                    zip.write_all(&data).unwrap();
+                }
+                zip.finish().unwrap()
+            })
+        });
+    }
+    group.finish();
+}
+
+criterion_group!(benches, bench_many_small_files);
+criterion_main!(benches);