[−][src]Crate rkyv
rkyv
rkyv (archive) is a zero-copy deserialization framework for Rust.
It's similar to other zero-copy deserialization frameworks such as Cap'n Proto and FlatBuffers. However, while the former have external schemas and heavily restricted data types, rkyv allows all serialized types to be defined in code and can serialize a wide variety of types that the others cannot. Additionally, rkyv is designed to have little to no overhead, and in most cases will perform exactly the same as native types.
rkyv has a hashmap implementation that is built for zero-copy
deserialization, so you can serialize your hashmaps with abandon!
The implementation is based off of the standard library's
hashbrown
crate and should have nearly identical performance.
One of the most impactful features made possible by rkyv is the
ability to serialize trait objects and use them as trait objects
without deserialization. See the archive_dyn
crate for more details.
Design
Like serde, rkyv uses Rust's powerful trait
system to serialize data without the need for reflection. Despite
having a wide array of features, you also only pay for what you
use. If your data checks out, the serialization process can be
as simple as a memcpy
! Like serde, this allows rkyv to perform
at speeds similar to handwritten serializers.
Unlike serde, rkyv produces data that is guaranteed deserialization
free. If you wrote your data to disk, you can just mmap
your file
into memory, cast a pointer, and your data is ready to use. This
makes it ideal for high-performance and IO-limited applications.
Tradeoffs
rkyv is designed primarily for loading bulk game data as efficiently as possible. While rkyv is a great format for final data, it lacks a full schema system and isn't well equipped for data migration. Using a serialization library like serde can help fill these gaps, and you can use serde with the same types as rkyv conflict-free.
Features
const_generics
: Improves the implementations for some traits and provides anArchive
implementation for slices with elements that implementArchiveSelf
. Ideal for#[no_std]
environments.inline_more
: Performs more aggressive function inlining.more_portable
: Avoids using sse2-optimized intrinsics since they may cause alignment issues across machines. This feature may go away once any portability bugs are identified and fixed.nightly
: Enables some nightly features, such aslikely
.specialization
: Enables the unfinished specialization feature and provides more efficient implementations of some functions when working withArchiveSelf
types.std
: Enables standard library support.
By default, the std
and inline_more
features are enabled.
Macros
offset_of | Calculates the offset of the specified field from the start of the named struct. |
Structs
Aligned | Wraps a type and aligns it to at least 16 bytes. Mainly used to align byte buffers for ArchiveBuffer. |
ArchiveBuffer | Wraps a byte buffer and writes into it. |
ArchiveWriter | Wraps a type that implements |
RelPtr | A strongly typed pointer which resolves to relative to its position in memory. |
SelfResolver | A resolver that always resolves to the unarchived value. This can be useful
while implementing |
Enums
ArchiveBufferError | The error type returned by an |
Traits
Archive | Writes a type to a |
ArchiveRef | This trait is a counterpart of |
ArchiveSelf | A trait that indicates that some |
Resolve | Creates an archived value when given a value and position. |
Write | A |
WriteExt | Helper functions on |
Type Definitions
Archived | Alias for the archived version of some |
Reference | Alias for the reference for some |
ReferenceResolver | Alias for the resolver of the reference for some |
Resolver | Alias for the resolver for some |
Derive Macros
Archive | Derives |