SIMD Json for Rust 
Rust port of extremely fast simdjson JSON parser with serde compatibility.
readme (for real!)
CPU target
For taking advantage of simdjson your system needs to be SIMD compatible. This means to compile with native cpu support and the given features. Look at The cargo config in this repository to get an example.
jemalloc
If you are writing perormance centric code, make sure to use jemalloc and not the system allocator (that has now become default in rust), it gives an very noticable boost imperformance.
serde
simd-json.rs is compatible with serde and serde-json. The Value types provided implement serializers and deserialisers. In addition to that simd-json.rs implements the Deserializer for the parser so it can deserialize anything that implements the serde Deserialize trait.
That said serde is contained in the serde_impl feature which is part of the default feature set, but it can be disabled.
serializing
sims-json.rs does not provide capabiltiy to serialize JSON data, serde-json does a good job at this and there would be very little won by re-implementing it.
unsafe
simd-json.rs uses a lot of unsafe code first of all since all SIMD-intrinsics are inherently unsafe and also to work around some bottlenecks safe rust code. So this requires extra scrutiny and do to this diligently testing takes 5 shapes:
- Poor old unit tests - to test general 'obvious' cases and edge cases as well as regressions
- Property based testing on valid json - tests if valid but random generated json parses the same in simd-json and in serde-json (floats here are excloded since slighty different parsing algorihtms lead to slighty different results)
- Property based testing on random 'human readable' data - make sure that randomly generated sequences of pritnable characters don't panic or crash the parser (they might and often error so - they are not valid json!)
- Property based testing on random byte sequences - make sure that no random set of bytes will crash the parser
- Fuzzing (using afl) - fuzz based on upstream simd pass/fail cases
This sure doens't ensure complete safetly but it does go a long way.
Other interesting things
There are also bindings for simdjson available here
License
simdjson-rs itself is licensed under either of
- Apache License, Version 2.0, (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
- MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT) at your option.
However it ports a lot of code from simdjson so their work and copyright on that should be respected along side.
The serde integration is based on their example and serde-json so again, their copyright should as well be respected.