45 lines
1.1 KiB
Rust
45 lines
1.1 KiB
Rust
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/// A simple map based on a vector for small integer keys. Space requirements
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/// are O(highest integer key).
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import option::none;
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import option::some;
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// FIXME: Should not be @; there's a bug somewhere in rustc that requires this
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// to be.
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type smallintmap[T] = @{mutable v: [mutable option::t<T>]};
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fn mk[@T]() -> smallintmap<T> {
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let v: [mutable option::t<T>] = ~[mutable];
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ret @{mutable v: v};
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}
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fn insert[@T](m: &smallintmap<T>, key: uint, val: &T) {
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vec::grow_set[option::t<T>](m.v, key, none[T], some[T](val));
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}
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fn find[@T](m: &smallintmap<T>, key: uint) -> option::t<T> {
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if key < vec::len[option::t<T>](m.v) { ret m.v.(key); }
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ret none[T];
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}
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fn get[@T](m: &smallintmap<T>, key: uint) -> T {
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alt find[T](m, key) {
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none[T]. { log_err "smallintmap::get(): key not present"; fail; }
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some[T](v) { ret v; }
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}
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}
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fn contains_key[@T](m: &smallintmap<T>, key: uint) -> bool {
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ret !option::is_none(find[T](m, key));
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}
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fn truncate[@T](m: &smallintmap<T>, len: uint) {
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m.v = vec::slice_mut[option::t<T>](m.v, 0u, len);
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}
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fn max_key[T](m: &smallintmap<T>) -> uint {
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ret vec::len[option::t<T>](m.v);
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}
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