byteview

An immutable byte slice that may be inlined, and can be partially cloned without heap allocation.

Think of it as a specialized Arc<[u8]> that can be inlined (skip allocation for small values) and no weak count.

byteview was designed to speed up deserialization in lsm-tree, allow inlining of small values and reduce memory usage compared to Arc'd slices. Values with a known length can be constructed 2-2.5x faster than using Arcs:

Memory usage

Allocating 200M "" (len=0) strings:

Struct	Memory Usage
Arc<[u8]>	9.6 GB
tokio::Bytes	6.4 GB
ByteView	4.8 GB

Allocating 200M "helloworld" (len=10) strings:

Struct	Memory Usage
Arc<[u8]>	12.8 GB
tokio::Bytes	12.8 GB
ByteView	4.8 GB

Allocating 100M "helloworldhelloworld" (len=20) strings:

Struct	Memory Usage
Arc<[u8]>	6.4 GB
tokio::Bytes	6.4 GB
ByteView	2.4 GB

Allocating 50M "helloworldhelloworldhelloworldhelloworld" (len=30) strings:

Struct	Memory Usage
Arc<[u8]>	4.0 GB
tokio::Bytes	4.0 GB
ByteView	3.6 GB

Allocating 500k "helloworld".repeat(1000) (len=10'000) strings:

Struct	Memory Usage
Arc<[u8]>	5 GB
tokio::Bytes	5 GB
ByteView	5 GB

Run fuzz tests

cargo +nightly fuzz run fuzz_target_1