fastnbt crate

Documentation: docs.rs

Fast deserializer and parser for Minecraft: Java Edition's NBT format.

Includes

• a serde based deserializer for NBT for deserialization.
• a lower level parser using the Read trait.

The derserializer allows you to avoid allocations where possible. Strings can be deserialized to &'a str where 'a is the lifetime of the data being deserialized. The borrow module contains more types for avoiding allocations.

See the documentation for more information.

toml [dependencies] fastnbt = "1"

fastnbt follows Semver, so any version 1 code you write should remain valid. Some things that this project does not count as a breaking change are:

• Minimum Rust version change. Outside of corporate environments this should not be too difficult, and I don't see much need for NBT in those environments.
• Improving the deserializer such that valid NBT that did not deserialize, then deserializes. Any of these cases I consider a bug.
• Data format when serializing types from fastnbt. Types in fastnbt implement serde::Serialise to enable spitting out to other data formats, but may change structure in future.

Changes that make fastnbt incompatible with WebAssembly are considered breaking changes.

Comparison to other NBT crates

There are other crates for NBT out there, this tries to give an honest comparison to them. The Hemtite nbt crate was the only other crate I found with serde deserialization.

| Feature | fastnbt | Hematite nbt | note | | ------- | --------- | -------------- | ---- | | Benchmark world render time (relative)* | 1.00 | 1.37 | fastnbt is ~37% faster. See note. | | Deserialization | yes | yes | | | Serialization | no | yes | | | Value-like type | yes | yes | fastnbt is careful to preserve exact types. | | Long Array (MC 1.12+) | yes | yes | | | Minecraft specialized unicode | yes | yes | | | Deserialize from reader | no | yes | | | WASM compatible | yes | unknown | |

* This is rendering the overworld of Etho's Lets Play Episode 550. Exact relative figures are 1000±13 for fastnbt and 1370±7 for hematite-nbt. This used the anvil tiles executable, swapping out the deserializer only, so performance tweaks in rendering chunks are not counted.