/rust-string-comparison

Choose Your Favorite String in Rust!

Choose Your Favorite String in Rust!

Memory efficiency

Type Crate Mutable Clone Hash Size1 SSO
String std Yes O(n) O(n) 24 bytes No
Box<str> std No O(n) O(n) 16 bytes + niche No
Arc<str> std No O(1) O(n) 16 bytes + niche No
FastStr faststr No O(1) O(n) 40 bytes + niche 24 bytes2
CompactString compact_str Yes O(n) O(n) 24 bytes + niche 23 bytes
SmolStr smol_str No O(1) O(n) 24 bytes + niche 22 bytes/WS3
Yarn byteyarn No O(1) O(n) 16 bytes + niche 15 bytes
ArcStr arcstr No O(1) O(n) 8 bytes + niche No
UStr ustr No O(1) O(1) 8 bytes + niche No
EcoString ecow Yes O(1)4 O(n) 16 bytes 15 bytes

Convention

Type Crate From String From Box<str> From Arc<str> From &'static str
String std - O(1) No O(n)
Box<str> std O(n) - No O(n)
Arc<str> std O(n) O(n) - O(n)
FastStr faststr O(n) O(n) O(1) O(1)
CompactString compact_str O(1) O(1) No O(1)
SmolStr smol_str O(n) O(n) O(1) O(1)
Yarn byteyarn O(n) O(1) No O(1)
ArcStr arcstr O(n) O(n) O(n) O(1)5
UStr ustr O(n) No No O(n)
EcoString ecow O(n) No No O(n)

Integration

Type Crate no-std MSRV serde bytes rkyv
FastStr faststr No 1.60 Yes Yes No
CompactString compact_str Yes 1.60 Yes Yes Yes
SmolStr smol_str Yes 1.60 Yes No No
Yarn byteyarn No 1.71 No No No
ArcStr arcstr Yes 1.57 Yes No No
UStr ustr No 1.60 Yes No No
EcoString ecow Yes 1.65 Yes No No

Audit

Type Crate Unsafe Dependencies6 License
FastStr faststr UTF-87 2 MIT/Apache
CompactString compact_str Yes 6 MIT
SmolStr smol_str Yes 0 MIT/Apache
Yarn byteyarn Yes 1 Apache 2.0
ArcStr arcstr Yes 0 Apache-2.0 OR MIT OR Zlib
UStr ustr Yes 4 BSD-2-Clause-Patent
EcoString ecow Yes 0 MIT/Apache

Footnotes

  1. based on x86_64 ↩

  2. not stable ↩

  3. SSO is also available for consecutive newlines and spaces ↩

  4. copy on write ↩

  5. only available for literal ↩

  6. optional or dev dependencies not counted ↩

  7. only used in UTF-8 validation ↩