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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:19:41 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:19:41 +0000 |
commit | 4f9fe856a25ab29345b90e7725509e9ee38a37be (patch) | |
tree | e4ffd8a9374cae7b21f7cbfb352927e0e074aff6 /vendor/elsa/examples/string_interner.rs | |
parent | Adding upstream version 1.68.2+dfsg1. (diff) | |
download | rustc-5cd5bd4daf55da04d2c8e7c06c3067a027cfbfc2.tar.xz rustc-5cd5bd4daf55da04d2c8e7c06c3067a027cfbfc2.zip |
Adding upstream version 1.69.0+dfsg1.upstream/1.69.0+dfsg1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | vendor/elsa/examples/string_interner.rs | 61 |
1 files changed, 61 insertions, 0 deletions
diff --git a/vendor/elsa/examples/string_interner.rs b/vendor/elsa/examples/string_interner.rs new file mode 100644 index 000000000..fd039f7ba --- /dev/null +++ b/vendor/elsa/examples/string_interner.rs @@ -0,0 +1,61 @@ +use std::collections::BTreeSet; +use std::convert::AsRef; + +use elsa::FrozenIndexSet; + +struct StringInterner { + set: FrozenIndexSet<String>, +} + +impl StringInterner { + fn new() -> Self { + StringInterner { + set: FrozenIndexSet::new(), + } + } + + fn get_or_intern<T>(&self, value: T) -> usize + where + T: AsRef<str>, + { + // TODO use Entry in case the standard Entry API gets improved + // (here to avoid premature allocation or double lookup) + self.set.insert_full(value.as_ref().to_string()).0 + } + + fn get<T>(&self, value: T) -> Option<usize> + where + T: AsRef<str>, + { + self.set.get_full(value.as_ref()).map(|(i, _r)| i) + } + + fn resolve(&self, index: usize) -> Option<&str> { + self.set.get_index(index) + } +} + +fn main() { + let interner = StringInterner::new(); + let lonely = interner.get_or_intern("lonely"); + let best_friend = interner.get_or_intern("best friend"); + let threes_a_crowd = interner.get_or_intern("threes a crowd"); + let rando = interner.get_or_intern("rando"); + let _facebook = interner.get_or_intern("facebook"); + + let best_friend_2 = interner.get_or_intern("best friend"); + let best_friend_3 = interner.get("best friend").unwrap(); + + let best_friend_ref = interner.resolve(best_friend).unwrap(); + + let mut set = BTreeSet::new(); + set.insert(lonely); + set.insert(best_friend); + set.insert(threes_a_crowd); + set.insert(rando); + set.insert(best_friend_2); + assert_eq!(set.len(), 4); + assert_eq!(best_friend, best_friend_2); + assert_eq!(best_friend_2, best_friend_3); + assert_eq!(best_friend_ref, "best friend"); +} |