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// Copyright 2014 The Servo Project Developers. See the COPYRIGHT // file at the top-level directory of this distribution. // // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your // option. This file may not be copied, modified, or distributed // except according to those terms. //! //! A library for interning things that are `AsRef<str>`. //! //! Some strings may be interned at compile time using the `string-cache-codegen` crate, or the //! `EmptyStaticAtomSet` may be used that has no compile-time interned strings. An `Atom` is an //! interned string for a given set (either `EmptyStaticAtomSet` or a generated `StaticAtomSet`). //! //! Generated `Atom`s will have assocated macros to intern static strings at compile-time. //! //! # Examples //! //! Here are two examples, one with compile-time `Atom`s, and one without. //! //! ## With compile-time atoms //! //! In `Cargo.toml`: //! ```toml //! [dependencies] //! string_cache = "0.8" //! //! [dev-dependencies] //! string_cache_codegen = "0.5" //! ``` //! //! In `build.rs`: //! //! ```ignore //! extern crate string_cache_codegen; //! //! use std::env; //! use std::path::Path; //! //! fn main() { //! string_cache_codegen::AtomType::new("foo::FooAtom", "foo_atom!") //! .atoms(&["foo", "bar"]) //! .write_to_file(&Path::new(&env::var("OUT_DIR").unwrap()).join("foo_atom.rs")) //! .unwrap() //! } //! ``` //! //! In `lib.rs`: //! //! ```ignore //! extern crate string_cache; //! //! mod foo { //! include!(concat!(env!("OUT_DIR"), "/foo_atom.rs")); //! } //! //! fn use_the_atom(t: &str) { //! match *t { //! foo_atom!("foo") => println!("Found foo!"), //! foo_atom!("bar") => println!("Found bar!"), //! // foo_atom!("baz") => println!("Found baz!"), - would be a compile time error //! _ => { //! println!("String not interned"); //! // We can intern strings at runtime as well //! foo::FooAtom::from(t) //! } //! } //! } //! ``` //! //! ## No compile-time atoms //! //! ``` //! # extern crate string_cache; //! use string_cache::DefaultAtom; //! //! # fn main() { //! let mut interned_stuff = Vec::new(); //! let text = "here is a sentence of text that will be tokenised and //! interned and some repeated tokens is of text and"; //! for word in text.split_whitespace() { //! let seen_before = interned_stuff.iter() //! // We can use impl PartialEq<T> where T is anything string-like //! // to compare to interned strings to either other interned strings, //! // or actual strings Comparing two interned strings is very fast //! // (normally a single cpu operation). //! .filter(|interned_word| interned_word == &word) //! .count(); //! if seen_before > 0 { //! println!(r#"Seen the word "{}" {} times"#, word, seen_before); //! } else { //! println!(r#"Not seen the word "{}" before"#, word); //! } //! // We use the impl From<(Cow<'a, str>, or &'a str, or String)> for //! // Atom<Static> to intern a new string. //! interned_stuff.push(DefaultAtom::from(word)); //! } //! # } //! ``` //! #![cfg_attr(test, deny(warnings))] mod atom; mod dynamic_set; mod static_sets; mod trivial_impls; pub use atom::Atom; pub use static_sets::{EmptyStaticAtomSet, PhfStrSet, StaticAtomSet}; /// Use this if you don’t care about static atoms. pub type DefaultAtom = Atom<EmptyStaticAtomSet>; // Some minor tests of internal layout here. // See ../integration-tests for much more. /// Guard against accidental changes to the sizes of things. #[test] fn assert_sizes() { use std::mem::size_of; assert_eq!(size_of::<DefaultAtom>(), 8); assert_eq!(size_of::<Option<DefaultAtom>>(), size_of::<DefaultAtom>(),); }