ljar/benches/inflate_bench.rs
//! Benchmarks for the inflate (DEFLATE decompression) pipeline.
//!
//! Covers: Huffman table build, inflate decode, and flush boundary scan.
use criterion::{Criterion, Throughput, criterion_group, criterion_main};
use std::hint::black_box;
// ── Test data generators ─────────────────────────────────────────────────────
fn make_repetitive_data(size: usize) -> Vec<u8> {
let pattern = b"The quick brown fox jumps over the lazy dog. ";
let repeats = (size / pattern.len()) + 2;
pattern.repeat(repeats)[..size].to_vec()
}
fn make_mixed_data(size: usize) -> Vec<u8> {
let mut v = Vec::with_capacity(size);
for i in 0..size {
if i % 10 < 3 {
v.push(0);
} else {
v.push(((i * 7 + 13) % 256) as u8);
}
}
v
}
fn make_class_like_data(size: usize) -> Vec<u8> {
let mut v = vec![0xCA, 0xFE, 0xBA, 0xBE, 0x00, 0x00, 0x00, 0x34];
let chunk = b"package org.example;\nimport java.util.*;\npublic class Foo {\n private final String name;\n}\n";
while v.len() < size {
v.extend_from_slice(chunk);
}
v.truncate(size);
v
}
// ── Inflate benchmarks ───────────────────────────────────────────────────────
fn bench_inflate(c: &mut Criterion) {
let mut group = c.benchmark_group("inflate");
// Repetitive 4K
{
let original = make_repetitive_data(4096);
let compressed = miniz_oxide::deflate::compress_to_vec(&original, 6);
group.throughput(Throughput::Bytes(original.len() as u64));
group.bench_function("repetitive_4k", |b| {
b.iter(|| {
black_box(ljar::inflate::inflate_to_vec(&compressed, original.len()).unwrap())
})
});
}
// Repetitive 64K
{
let original = make_repetitive_data(65536);
let compressed = miniz_oxide::deflate::compress_to_vec(&original, 6);
group.throughput(Throughput::Bytes(original.len() as u64));
group.bench_function("repetitive_64k", |b| {
b.iter(|| {
black_box(ljar::inflate::inflate_to_vec(&compressed, original.len()).unwrap())
})
});
}
// Repetitive 256K
{
let original = make_repetitive_data(256 * 1024);
let compressed = miniz_oxide::deflate::compress_to_vec(&original, 6);
group.throughput(Throughput::Bytes(original.len() as u64));
group.bench_function("repetitive_256k", |b| {
b.iter(|| {
black_box(ljar::inflate::inflate_to_vec(&compressed, original.len()).unwrap())
})
});
}
// Mixed 64K
{
let original = make_mixed_data(65536);
let compressed = miniz_oxide::deflate::compress_to_vec(&original, 6);
group.throughput(Throughput::Bytes(original.len() as u64));
group.bench_function("mixed_64k", |b| {
b.iter(|| {
black_box(ljar::inflate::inflate_to_vec(&compressed, original.len()).unwrap())
})
});
}
// Class-like 64K
{
let original = make_class_like_data(65536);
let compressed = miniz_oxide::deflate::compress_to_vec(&original, 6);
group.throughput(Throughput::Bytes(original.len() as u64));
group.bench_function("class_like_64k", |b| {
b.iter(|| {
black_box(ljar::inflate::inflate_to_vec(&compressed, original.len()).unwrap())
})
});
}
group.finish();
}
// ── Table build benchmarks ───────────────────────────────────────────────────
fn bench_table_build(c: &mut Criterion) {
let mut group = c.benchmark_group("table_build");
// Fixed litlen table (288 symbols, realistic)
let mut lens = [0u8; 288];
for i in 0..=143 {
lens[i] = 8;
}
for i in 144..=255 {
lens[i] = 9;
}
for i in 256..=279 {
lens[i] = 7;
}
for i in 280..=287 {
lens[i] = 8;
}
group.bench_function("litlen_288sym", |b| {
b.iter(|| {
let mut table = [0u32; ljar::inflate::tables::LITLEN_TABLE_SIZE];
black_box(
ljar::inflate::tables::build_decode_table(
&lens,
&mut table,
ljar::inflate::tables::LITLEN_TABLEBITS,
ljar::inflate::tables::TableKind::Litlen,
)
.unwrap(),
);
})
});
// Distance table (30 symbols)
let dist_lens = [5u8; 32];
group.bench_function("dist_32sym", |b| {
b.iter(|| {
let mut table = [0u32; ljar::inflate::tables::DIST_TABLE_SIZE];
black_box(
ljar::inflate::tables::build_decode_table(
&dist_lens,
&mut table,
ljar::inflate::tables::DIST_TABLEBITS,
ljar::inflate::tables::TableKind::Dist,
)
.unwrap(),
);
})
});
group.finish();
}
// ── Deflate scan benchmarks ──────────────────────────────────────────────────
fn bench_flush_scan(c: &mut Criterion) {
let mut group = c.benchmark_group("flush_scan");
// 1MB with markers
{
let mut buf = vec![0xAAu8; 1024 * 1024];
for pos in [100_000, 300_000, 600_000, 900_000] {
buf[pos] = 0x00;
buf[pos + 1] = 0x00;
buf[pos + 2] = 0xFF;
buf[pos + 3] = 0xFF;
}
group.throughput(Throughput::Bytes(buf.len() as u64));
group.bench_function("with_markers_1mb", |b| {
b.iter(|| black_box(ljar::deflate_scan::find_all_flushes(&buf)))
});
}
// 1MB no match (worst case)
{
let buf = vec![0x42u8; 1024 * 1024];
group.throughput(Throughput::Bytes(buf.len() as u64));
group.bench_function("no_match_1mb", |b| {
b.iter(|| black_box(ljar::deflate_scan::find_all_flushes(&buf)))
});
}
group.finish();
}
// ── Comparison vs miniz_oxide ────────────────────────────────────────────────
fn bench_vs_miniz(c: &mut Criterion) {
let mut group = c.benchmark_group("inflate_vs_miniz");
let original = make_repetitive_data(65536);
let compressed = miniz_oxide::deflate::compress_to_vec(&original, 6);
group.throughput(Throughput::Bytes(original.len() as u64));
group.bench_function("ljar_64k", |b| {
b.iter(|| black_box(ljar::inflate::inflate_to_vec(&compressed, original.len()).unwrap()))
});
group.bench_function("miniz_oxide_64k", |b| {
b.iter(|| black_box(miniz_oxide::inflate::decompress_to_vec(&compressed).unwrap()))
});
let original_256k = make_repetitive_data(256 * 1024);
let compressed_256k = miniz_oxide::deflate::compress_to_vec(&original_256k, 6);
group.throughput(Throughput::Bytes(original_256k.len() as u64));
group.bench_function("ljar_256k", |b| {
b.iter(|| {
black_box(ljar::inflate::inflate_to_vec(&compressed_256k, original_256k.len()).unwrap())
})
});
group.bench_function("miniz_oxide_256k", |b| {
b.iter(|| black_box(miniz_oxide::inflate::decompress_to_vec(&compressed_256k).unwrap()))
});
group.finish();
}
criterion_group!(
benches,
bench_inflate,
bench_table_build,
bench_flush_scan,
bench_vs_miniz
);
criterion_main!(benches);