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Migrate to Copy-on-Write (Cow) for zero-copy decoding support #40

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Merged
moreal merged 2 commits into from
Feb 1, 2026
Merged

Migrate to Copy-on-Write (Cow) for zero-copy decoding support #40

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0219b83
Migrate to Copy-on-Write (Cow) for zero-copy decoding support
moreal Feb 1, 2026
2e02f33
Avoid into_owned() tree rebuild in Decode for Vec<u8>
moreal Feb 1, 2026
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36 changes: 33 additions & 3 deletions benches/decode.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -30,6 +30,24 @@ macro_rules! bench_decode_files {
};
}

/// Macro for easily adding benchmark data files (borrowed / zero-copy)
macro_rules! bench_decode_files_borrowed {
($group:expr, $( $name:literal => $path:literal ),* $(,)?) => {
$(
{
const DATA: &[u8] = include_bytes!($path);
let size_str = format_size(DATA.len());
let bench_name = format!("{} ({})", $name, size_str);

$group.throughput(Throughput::Bytes(DATA.len() as u64));
$group.bench_function(&bench_name, |b| {
b.iter(|| bencodex::decode_borrowed(black_box(DATA)))
});
}
)*
};
}

/// Macro for easily adding benchmark data files (SIMD)
#[cfg(feature = "simd")]
macro_rules! bench_decode_files_simd {
Expand All @@ -42,7 +60,7 @@ macro_rules! bench_decode_files_simd {

$group.throughput(Throughput::Bytes(DATA.len() as u64));
$group.bench_function(&bench_name, |b| {
b.iter(|| black_box(DATA.to_vec()).decode_simd())
b.iter(|| bencodex::simd::decode_simd(black_box(DATA)))
});
}
)*
Expand All @@ -61,6 +79,18 @@ pub fn decode_scalar(c: &mut Criterion) {
group.finish();
}

pub fn decode_borrowed(c: &mut Criterion) {
let mut group = c.benchmark_group("decode_borrowed");

bench_decode_files_borrowed!(group,
"ncavatar_1" => "../_data/ncavatar_1.bin",
"ncinventory_1" => "../_data/ncinventory_1.bin",
"large_random_0" => "../_data/large_random_0.bin",
);

group.finish();
}

#[cfg(feature = "simd")]
pub fn decode_simd(c: &mut Criterion) {
let mut group = c.benchmark_group("decode_simd");
Expand All @@ -75,9 +105,9 @@ pub fn decode_simd(c: &mut Criterion) {
}

#[cfg(feature = "simd")]
criterion_group!(benches, decode_scalar, decode_simd);
criterion_group!(benches, decode_scalar, decode_borrowed, decode_simd);

#[cfg(not(feature = "simd"))]
criterion_group!(benches, decode_scalar);
criterion_group!(benches, decode_scalar, decode_borrowed);

criterion_main!(benches);
13 changes: 8 additions & 5 deletions benches/encode.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -30,7 +30,7 @@ macro_rules! bench_encode_files {
$group.bench_function(&bench_name, |b| {
b.iter(|| {
let mut buf = Vec::with_capacity(DATA.len());
black_box(value.clone()).encode(&mut buf)
black_box(&value).encode(&mut buf)
})
});
}
Expand Down Expand Up @@ -68,21 +68,24 @@ pub fn encode_primitives(c: &mut Criterion) {
let mut group = c.benchmark_group("encode_primitives");

group.bench_function("null", |b| {
let null = BencodexValue::Null;
let mut buf = Vec::new();
b.iter(|| black_box(BencodexValue::Null).encode(&mut buf));
b.iter(|| black_box(&null).encode(&mut buf));
});
group.bench_function("bigint (9223372036854775807)", |b| {
let mut buf = Vec::new();
let bigint = BencodexValue::Number(BigInt::from(9223372036854775807i64));
b.iter(|| black_box(bigint.clone()).encode(&mut buf));
b.iter(|| black_box(&bigint).encode(&mut buf));
});
group.bench_function("boolean (true)", |b| {
let val = BencodexValue::Boolean(true);
let mut buf = Vec::new();
b.iter(|| black_box(BencodexValue::Boolean(true)).encode(&mut buf));
b.iter(|| black_box(&val).encode(&mut buf));
});
group.bench_function("boolean (false)", |b| {
let val = BencodexValue::Boolean(false);
let mut buf = Vec::new();
b.iter(|| black_box(BencodexValue::Boolean(false)).encode(&mut buf));
b.iter(|| black_box(&val).encode(&mut buf));
});

group.finish();
Expand Down
29 changes: 15 additions & 14 deletions examples/generate_test_data.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,7 @@ use bencodex::{BencodexDictionary, BencodexKey, BencodexList, BencodexValue, Enc
use num_bigint::BigInt;
use rand::distr::Alphanumeric;
use rand::prelude::*;
use std::borrow::Cow;
use std::collections::BTreeMap;
use std::fs::File;
use std::io::Write;
Expand Down Expand Up @@ -53,25 +54,25 @@ fn random_number(rng: &mut impl Rng) -> BigInt {
BigInt::from_signed_bytes_le(&bytes)
}

fn random_key(rng: &mut impl Rng) -> BencodexKey {
fn random_key(rng: &mut impl Rng) -> BencodexKey<'static> {
if rng.random_bool(0.7) {
BencodexKey::Text(random_text(rng, 32))
BencodexKey::Text(Cow::Owned(random_text(rng, 32)))
} else {
BencodexKey::Binary(random_binary(rng, 32))
BencodexKey::Binary(Cow::Owned(random_binary(rng, 32)))
}
}

fn random_primitive(rng: &mut impl Rng) -> BencodexValue {
fn random_primitive(rng: &mut impl Rng) -> BencodexValue<'static> {
match rng.random_range(0..5) {
0 => BencodexValue::Null,
1 => BencodexValue::Boolean(rng.random()),
2 => BencodexValue::Number(random_number(rng)),
3 => BencodexValue::Text(random_text(rng, 100)),
_ => BencodexValue::Binary(random_binary(rng, 1000)),
3 => BencodexValue::Text(Cow::Owned(random_text(rng, 100))),
_ => BencodexValue::Binary(Cow::Owned(random_binary(rng, 1000))),
}
}

fn random_value(rng: &mut impl Rng, depth: usize) -> BencodexValue {
fn random_value(rng: &mut impl Rng, depth: usize) -> BencodexValue<'static> {
if depth >= MAX_DEPTH {
return random_primitive(rng);
}
Expand All @@ -93,31 +94,31 @@ fn random_value(rng: &mut impl Rng, depth: usize) -> BencodexValue {
}
}

fn generate_large_value(rng: &mut impl Rng, config: &GeneratorConfig) -> BencodexValue {
fn generate_large_value(rng: &mut impl Rng, config: &GeneratorConfig) -> BencodexValue<'static> {
let mut dict = BTreeMap::new();

for i in 0..config.binary_chunks {
let key = BencodexKey::Text(format!("binary_chunk_{i}"));
let value = BencodexValue::Binary(random_binary(rng, config.binary_max_size));
let key = BencodexKey::Text(Cow::Owned(format!("binary_chunk_{i}")));
let value = BencodexValue::Binary(Cow::Owned(random_binary(rng, config.binary_max_size)));
dict.insert(key, value);
}

for i in 0..config.number_lists {
let key = BencodexKey::Text(format!("number_list_{i}"));
let key = BencodexKey::Text(Cow::Owned(format!("number_list_{i}")));
let list: BencodexList = (0..config.numbers_per_list)
.map(|_| BencodexValue::Number(random_number(rng)))
.collect();
dict.insert(key, BencodexValue::List(list));
}

for i in 0..config.nested_entries {
let key = BencodexKey::Text(format!("nested_{i}"));
let key = BencodexKey::Text(Cow::Owned(format!("nested_{i}")));
dict.insert(key, random_value(rng, 0));
}

for i in 0..config.text_entries {
let key = BencodexKey::Text(format!("text_{i}"));
let value = BencodexValue::Text(random_text(rng, config.text_max_size));
let key = BencodexKey::Text(Cow::Owned(format!("text_{i}")));
let value = BencodexValue::Text(Cow::Owned(random_text(rng, config.text_max_size)));
dict.insert(key, value);
}

Expand Down
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