mozilla-central/third_party/rust/smallvec/src
Name Description Size
arbitrary.rs 570
lib.rs Small vectors in various sizes. These store a certain number of elements inline, and fall back to the heap for larger allocations. This can be a useful optimization for improving cache locality and reducing allocator traffic for workloads that fit within the inline buffer. ## `no_std` support By default, `smallvec` does not depend on `std`. However, the optional `write` feature implements the `std::io::Write` trait for vectors of `u8`. When this feature is enabled, `smallvec` depends on `std`. ## Optional features ### `serde` When this optional dependency is enabled, `SmallVec` implements the `serde::Serialize` and `serde::Deserialize` traits. ### `write` When this feature is enabled, `SmallVec<[u8; _]>` implements the `std::io::Write` trait. This feature is not compatible with `#![no_std]` programs. ### `union` **This feature requires Rust 1.49.** When the `union` feature is enabled `smallvec` will track its state (inline or spilled) without the use of an enum tag, reducing the size of the `smallvec` by one machine word. This means that there is potentially no space overhead compared to `Vec`. Note that `smallvec` can still be larger than `Vec` if the inline buffer is larger than two machine words. To use this feature add `features = ["union"]` in the `smallvec` section of Cargo.toml. Note that this feature requires Rust 1.49. Tracking issue: [rust-lang/rust#55149](https://github.com/rust-lang/rust/issues/55149) ### `const_generics` **This feature requires Rust 1.51.** When this feature is enabled, `SmallVec` works with any arrays of any size, not just a fixed list of sizes. ### `const_new` **This feature requires Rust 1.51.** This feature exposes the functions [`SmallVec::new_const`], [`SmallVec::from_const`], and [`smallvec_inline`] which enables the `SmallVec` to be initialized from a const context. For details, see the [Rust Reference](https://doc.rust-lang.org/reference/const_eval.html#const-functions). ### `drain_filter` **This feature is unstable.** It may change to match the unstable `drain_filter` method in libstd. Enables the `drain_filter` method, which produces an iterator that calls a user-provided closure to determine which elements of the vector to remove and yield from the iterator. ### `drain_keep_rest` **This feature is unstable.** It may change to match the unstable `drain_keep_rest` method in libstd. Enables the `DrainFilter::keep_rest` method. ### `specialization` **This feature is unstable and requires a nightly build of the Rust toolchain.** When this feature is enabled, `SmallVec::from(slice)` has improved performance for slices of `Copy` types. (Without this feature, you can use `SmallVec::from_slice` to get optimal performance for `Copy` types.) Tracking issue: [rust-lang/rust#31844](https://github.com/rust-lang/rust/issues/31844) ### `may_dangle` **This feature is unstable and requires a nightly build of the Rust toolchain.** This feature makes the Rust compiler less strict about use of vectors that contain borrowed references. For details, see the [Rustonomicon](https://doc.rust-lang.org/1.42.0/nomicon/dropck.html#an-escape-hatch). Tracking issue: [rust-lang/rust#34761](https://github.com/rust-lang/rust/issues/34761) 79053
specialization.rs Implementations that require `default fn`. 611
tests.rs 26074