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diff --git a/vendor/bytecount/README.md b/vendor/bytecount/README.md new file mode 100644 index 000000000..9847c2a89 --- /dev/null +++ b/vendor/bytecount/README.md @@ -0,0 +1,75 @@ +# bytecount + +Counting bytes really fast + +[](https://travis-ci.org/llogiq/bytecount) +[](https://ci.appveyor.com/project/llogiq/bytecount) +[](https://crates.io/crates/bytecount) +[](#license) + +This uses the "hyperscreamingcount" algorithm by Joshua Landau to count bytes faster than anything else. +The [newlinebench](https://github.com/llogiq/newlinebench) repository has further benchmarks for old versions of this repository. + +To use bytecount in your crate, if you have [cargo-edit](https://github.com/killercup/cargo-edit), just type +`cargo add bytecount` in a terminal with the crate root as the current path. Otherwise you can manually edit your +`Cargo.toml` to add `bytecount = 0.5.1` to your `[dependencies]` section. + +In your crate root (`lib.rs` or `main.rs`, depending on if you are writing a +library or application), add `extern crate bytecount;`. Now you can simply use +`bytecount::count` as follows: + +```Rust +extern crate bytecount; + +fn main() { + let mytext = "some potentially large text, perhaps read from disk?"; + let spaces = bytecount::count(mytext.as_bytes(), b' '); + .. +} +``` + +bytecount supports two features to make use of modern CPU's features to speed up counting considerably. To allow your +users to use them, add the following to your `Cargo.toml`: + +``` +[features] +runtime-dispatch-simd = ["bytecount/runtime-dispatch-simd"] +generic-simd = ["bytecount/generic-simd"] +``` + +The first, `runtime-dispatch-simd`, enables detection of SIMD capabilities at runtime, which allows using the SSE2 and +AVX2 codepaths, but cannot be used with `no_std`. + +Your users can then compile with runtime dispatch using: + +``` +cargo build --release --features runtime-dispatch-simd +``` + +The second, `generic-simd`, uses `packed_simd` to provide a fast +architecture-agnostic SIMD codepath, but requires running on nightly. + +Your users can compile with this codepath using: + +``` +cargo build --release --features generic-simd +``` + +Building for a more specific architecture will also improve performance. +You can do this with + +``` +RUSTFLAGS="-C target-cpu=native" cargo build --release +``` + +The scalar algorithm is explained in depth [here](https://llogiq.github.io/2016/09/27/count.html). + +**Note: Versions until 0.4.0 worked with Rust as of 1.20.0. Version 0.5.0 until 0.6.0 requires Rust 1.26 or later, +and at least 1.27.2 to use SIMD. Versions from 0.6.0 require Rust 1.32.0 or later.** + +## License + +Licensed under either of at your discretion: + +- [Apache 2.0](LICENSE.Apache2) +- [MIT](LICENSE.MIT) |