311 lines
9.9 KiB
Rust
311 lines
9.9 KiB
Rust
//! A deque. Untested as of yet. Likely buggy
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import option::{some, none};
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import dvec::{DVec, dvec};
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trait t<T> {
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fn size() -> uint;
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fn add_front(T);
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fn add_back(T);
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fn pop_front() -> T;
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fn pop_back() -> T;
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fn peek_front() -> T;
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fn peek_back() -> T;
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fn get(int) -> T;
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}
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// FIXME (#2343) eventually, a proper datatype plus an exported impl would
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// be preferrable.
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fn create<T: copy>() -> t<T> {
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type cell<T> = option<T>;
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let initial_capacity: uint = 32u; // 2^5
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/**
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* Grow is only called on full elts, so nelts is also len(elts), unlike
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* elsewhere.
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*/
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fn grow<T: copy>(nelts: uint, lo: uint, -elts: ~[mut cell<T>]) ->
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~[mut cell<T>] {
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assert (nelts == vec::len(elts));
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let mut rv = ~[mut];
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let mut i = 0u;
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let nalloc = uint::next_power_of_two(nelts + 1u);
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while i < nalloc {
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if i < nelts {
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vec::push(rv, elts[(lo + i) % nelts]);
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} else { vec::push(rv, none); }
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i += 1u;
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}
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return rv;
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}
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fn get<T: copy>(elts: DVec<cell<T>>, i: uint) -> T {
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match elts.get_elt(i) { some(t) => t, _ => fail }
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}
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type repr<T> = {mut nelts: uint,
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mut lo: uint,
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mut hi: uint,
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elts: DVec<cell<T>>};
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impl <T: copy> repr<T>: t<T> {
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fn size() -> uint { return self.nelts; }
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fn add_front(t: T) {
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let oldlo: uint = self.lo;
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if self.lo == 0u {
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self.lo = self.elts.len() - 1u;
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} else { self.lo -= 1u; }
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if self.lo == self.hi {
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self.elts.swap(|v| grow(self.nelts, oldlo, v));
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self.lo = self.elts.len() - 1u;
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self.hi = self.nelts;
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}
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self.elts.set_elt(self.lo, some(t));
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self.nelts += 1u;
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}
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fn add_back(t: T) {
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if self.lo == self.hi && self.nelts != 0u {
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self.elts.swap(|v| grow(self.nelts, self.lo, v));
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self.lo = 0u;
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self.hi = self.nelts;
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}
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self.elts.set_elt(self.hi, some(t));
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self.hi = (self.hi + 1u) % self.elts.len();
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self.nelts += 1u;
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}
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/**
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* We actually release (turn to none()) the T we're popping so
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* that we don't keep anyone's refcount up unexpectedly.
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*/
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fn pop_front() -> T {
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let t: T = get(self.elts, self.lo);
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self.elts.set_elt(self.lo, none);
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self.lo = (self.lo + 1u) % self.elts.len();
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self.nelts -= 1u;
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return t;
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}
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fn pop_back() -> T {
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if self.hi == 0u {
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self.hi = self.elts.len() - 1u;
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} else { self.hi -= 1u; }
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let t: T = get(self.elts, self.hi);
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self.elts.set_elt(self.hi, none);
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self.nelts -= 1u;
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return t;
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}
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fn peek_front() -> T { return get(self.elts, self.lo); }
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fn peek_back() -> T { return get(self.elts, self.hi - 1u); }
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fn get(i: int) -> T {
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let idx = (self.lo + (i as uint)) % self.elts.len();
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return get(self.elts, idx);
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}
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}
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let repr: repr<T> = {
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mut nelts: 0u,
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mut lo: 0u,
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mut hi: 0u,
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elts:
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dvec::from_vec(
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vec::to_mut(
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vec::from_elem(initial_capacity, none)))
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};
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repr as t::<T>
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}
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#[cfg(test)]
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mod tests {
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#[test]
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fn test_simple() {
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let d: deque::t<int> = deque::create::<int>();
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assert (d.size() == 0u);
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d.add_front(17);
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d.add_front(42);
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d.add_back(137);
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assert (d.size() == 3u);
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d.add_back(137);
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assert (d.size() == 4u);
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log(debug, d.peek_front());
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assert (d.peek_front() == 42);
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log(debug, d.peek_back());
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assert (d.peek_back() == 137);
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let mut i: int = d.pop_front();
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log(debug, i);
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assert (i == 42);
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i = d.pop_back();
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log(debug, i);
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assert (i == 137);
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i = d.pop_back();
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log(debug, i);
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assert (i == 137);
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i = d.pop_back();
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log(debug, i);
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assert (i == 17);
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assert (d.size() == 0u);
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d.add_back(3);
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assert (d.size() == 1u);
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d.add_front(2);
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assert (d.size() == 2u);
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d.add_back(4);
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assert (d.size() == 3u);
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d.add_front(1);
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assert (d.size() == 4u);
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log(debug, d.get(0));
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log(debug, d.get(1));
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log(debug, d.get(2));
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log(debug, d.get(3));
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assert (d.get(0) == 1);
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assert (d.get(1) == 2);
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assert (d.get(2) == 3);
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assert (d.get(3) == 4);
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}
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fn test_boxes(a: @int, b: @int, c: @int, d: @int) {
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let deq: deque::t<@int> = deque::create::<@int>();
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assert (deq.size() == 0u);
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deq.add_front(a);
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deq.add_front(b);
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deq.add_back(c);
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assert (deq.size() == 3u);
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deq.add_back(d);
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assert (deq.size() == 4u);
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assert (deq.peek_front() == b);
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assert (deq.peek_back() == d);
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assert (deq.pop_front() == b);
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assert (deq.pop_back() == d);
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assert (deq.pop_back() == c);
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assert (deq.pop_back() == a);
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assert (deq.size() == 0u);
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deq.add_back(c);
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assert (deq.size() == 1u);
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deq.add_front(b);
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assert (deq.size() == 2u);
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deq.add_back(d);
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assert (deq.size() == 3u);
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deq.add_front(a);
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assert (deq.size() == 4u);
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assert (deq.get(0) == a);
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assert (deq.get(1) == b);
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assert (deq.get(2) == c);
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assert (deq.get(3) == d);
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}
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type eqfn<T> = fn@(T, T) -> bool;
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fn test_parameterized<T: copy owned>(
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e: eqfn<T>, a: T, b: T, c: T, d: T) {
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let deq: deque::t<T> = deque::create::<T>();
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assert (deq.size() == 0u);
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deq.add_front(a);
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deq.add_front(b);
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deq.add_back(c);
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assert (deq.size() == 3u);
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deq.add_back(d);
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assert (deq.size() == 4u);
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assert (e(deq.peek_front(), b));
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assert (e(deq.peek_back(), d));
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assert (e(deq.pop_front(), b));
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assert (e(deq.pop_back(), d));
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assert (e(deq.pop_back(), c));
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assert (e(deq.pop_back(), a));
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assert (deq.size() == 0u);
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deq.add_back(c);
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assert (deq.size() == 1u);
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deq.add_front(b);
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assert (deq.size() == 2u);
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deq.add_back(d);
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assert (deq.size() == 3u);
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deq.add_front(a);
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assert (deq.size() == 4u);
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assert (e(deq.get(0), a));
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assert (e(deq.get(1), b));
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assert (e(deq.get(2), c));
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assert (e(deq.get(3), d));
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}
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enum taggy { one(int), two(int, int), three(int, int, int), }
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enum taggypar<T> {
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onepar(int), twopar(int, int), threepar(int, int, int),
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}
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type reccy = {x: int, y: int, t: taggy};
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#[test]
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fn test() {
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fn inteq(&&a: int, &&b: int) -> bool { return a == b; }
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fn intboxeq(&&a: @int, &&b: @int) -> bool { return a == b; }
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fn taggyeq(a: taggy, b: taggy) -> bool {
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match a {
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one(a1) => match b {
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one(b1) => return a1 == b1,
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_ => return false
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},
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two(a1, a2) => match b {
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two(b1, b2) => return a1 == b1 && a2 == b2,
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_ => return false
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},
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three(a1, a2, a3) => match b {
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three(b1, b2, b3) => return a1 == b1 && a2 == b2 && a3 == b3,
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_ => return false
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}
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}
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}
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fn taggypareq<T>(a: taggypar<T>, b: taggypar<T>) -> bool {
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match a {
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onepar::<T>(a1) => match b {
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onepar::<T>(b1) => return a1 == b1,
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_ => return false
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},
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twopar::<T>(a1, a2) => match b {
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twopar::<T>(b1, b2) => return a1 == b1 && a2 == b2,
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_ => return false
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},
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threepar::<T>(a1, a2, a3) => match b {
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threepar::<T>(b1, b2, b3) => {
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return a1 == b1 && a2 == b2 && a3 == b3
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}
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_ => return false
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}
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}
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}
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fn reccyeq(a: reccy, b: reccy) -> bool {
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return a.x == b.x && a.y == b.y && taggyeq(a.t, b.t);
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}
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debug!("*** test boxes");
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test_boxes(@5, @72, @64, @175);
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debug!("*** end test boxes");
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debug!("test parameterized: int");
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let eq1: eqfn<int> = inteq;
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test_parameterized::<int>(eq1, 5, 72, 64, 175);
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debug!("*** test parameterized: @int");
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let eq2: eqfn<@int> = intboxeq;
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test_parameterized::<@int>(eq2, @5, @72, @64, @175);
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debug!("*** end test parameterized @int");
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debug!("test parameterized: taggy");
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let eq3: eqfn<taggy> = taggyeq;
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test_parameterized::<taggy>(eq3, one(1), two(1, 2), three(1, 2, 3),
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two(17, 42));
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debug!("*** test parameterized: taggypar<int>");
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let eq4: eqfn<taggypar<int>> = |x,y| taggypareq::<int>(x, y);
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test_parameterized::<taggypar<int>>(eq4, onepar::<int>(1),
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twopar::<int>(1, 2),
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threepar::<int>(1, 2, 3),
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twopar::<int>(17, 42));
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debug!("*** end test parameterized: taggypar::<int>");
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debug!("*** test parameterized: reccy");
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let reccy1: reccy = {x: 1, y: 2, t: one(1)};
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let reccy2: reccy = {x: 345, y: 2, t: two(1, 2)};
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let reccy3: reccy = {x: 1, y: 777, t: three(1, 2, 3)};
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let reccy4: reccy = {x: 19, y: 252, t: two(17, 42)};
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let eq5: eqfn<reccy> = reccyeq;
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test_parameterized::<reccy>(eq5, reccy1, reccy2, reccy3, reccy4);
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debug!("*** end test parameterized: reccy");
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debug!("*** done");
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}
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}
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