1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94
use std::collections::HashMap; use std::cell::RefCell; use std::fmt::{Debug, Display, Error, Formatter}; use std::cmp::{PartialOrd, Ord, Ordering}; #[cfg(test)] mod test; thread_local! { static INTERNER_TLS: RefCell<Interner> = RefCell::new(Interner::new()) } pub struct Interner { map: HashMap<String, InternedString>, strings: Vec<String>, } #[derive(Copy, Clone, Hash, Eq, PartialEq)] pub struct InternedString { index: u32 } pub fn intern(s: &str) -> InternedString { write(|interner| { match interner.map.get(s) { Some(&v) => { return v; } None => { } } let index = interner.strings.len() as u32; let result = InternedString { index: index }; interner.map.insert(s.to_string(), result); interner.strings.push(s.to_string()); return result; }) } pub fn read<F,R>(f: F) -> R where F: FnOnce(&Interner) -> R { INTERNER_TLS.with(|interner| f(&*interner.borrow())) } fn write<F,R>(f: F) -> R where F: FnOnce(&mut Interner) -> R { INTERNER_TLS.with(|interner| f(&mut *interner.borrow_mut())) } impl Interner { fn new() -> Interner { Interner { map: HashMap::new(), strings: vec![] } } pub fn data(&self, i: InternedString) -> &str { &self.strings[i.index()] } } impl InternedString { fn index(&self) -> usize { self.index as usize } pub fn starts_with(&self, prefix: &str) -> bool { read(|interner| interner.data(*self).starts_with(prefix)) } } impl Debug for InternedString { fn fmt(&self, fmt: &mut Formatter) -> Result<(), Error> { read(|interner| Debug::fmt(&interner.data(*self), fmt)) } } impl Display for InternedString { fn fmt(&self, fmt: &mut Formatter) -> Result<(), Error> { read(|interner| Display::fmt(&interner.data(*self), fmt)) } } impl PartialOrd<InternedString> for InternedString { fn partial_cmp(&self, other: &InternedString) -> Option<Ordering> { read(|interner| PartialOrd::partial_cmp(interner.data(*self), interner.data(*other))) } } impl Ord for InternedString { fn cmp(&self, other: &InternedString) -> Ordering { read(|interner| Ord::cmp(interner.data(*self), interner.data(*other))) } }