rust/src/libstd/deque.rs

327 lines
9.9 KiB
Rust

//! A deque. Untested as of yet. Likely buggy
#[forbid(deprecated_mode)];
#[forbid(deprecated_pattern)];
#[forbid(non_camel_case_types)];
use option::{Some, None};
use dvec::DVec;
use core::cmp::{Eq};
trait Deque<T> {
fn size() -> uint;
fn add_front(T);
fn add_back(T);
fn pop_front() -> T;
fn pop_back() -> T;
fn peek_front() -> T;
fn peek_back() -> T;
fn get(int) -> T;
}
// FIXME (#2343) eventually, a proper datatype plus an exported impl would
// be preferrable.
fn create<T: Copy>() -> Deque<T> {
type Cell<T> = Option<T>;
let initial_capacity: uint = 32u; // 2^5
/**
* Grow is only called on full elts, so nelts is also len(elts), unlike
* elsewhere.
*/
fn grow<T: Copy>(nelts: uint, lo: uint, +elts: ~[Cell<T>])
-> ~[Cell<T>] {
let mut elts = move elts;
assert (nelts == vec::len(elts));
let mut rv = ~[];
let mut i = 0u;
let nalloc = uint::next_power_of_two(nelts + 1u);
while i < nalloc {
if i < nelts {
vec::push(rv, elts[(lo + i) % nelts]);
} else { vec::push(rv, None); }
i += 1u;
}
move rv
}
fn get<T: Copy>(elts: &DVec<Cell<T>>, i: uint) -> T {
match (*elts).get_elt(i) { Some(t) => t, _ => fail }
}
type Repr<T> = {mut nelts: uint,
mut lo: uint,
mut hi: uint,
elts: DVec<Cell<T>>};
impl <T: Copy> Repr<T>: Deque<T> {
fn size() -> uint { return self.nelts; }
fn add_front(t: T) {
let oldlo: uint = self.lo;
if self.lo == 0u {
self.lo = self.elts.len() - 1u;
} else { self.lo -= 1u; }
if self.lo == self.hi {
self.elts.swap(|v| grow(self.nelts, oldlo, move v));
self.lo = self.elts.len() - 1u;
self.hi = self.nelts;
}
self.elts.set_elt(self.lo, Some(t));
self.nelts += 1u;
}
fn add_back(t: T) {
if self.lo == self.hi && self.nelts != 0u {
self.elts.swap(|v| grow(self.nelts, self.lo, move v));
self.lo = 0u;
self.hi = self.nelts;
}
self.elts.set_elt(self.hi, Some(t));
self.hi = (self.hi + 1u) % self.elts.len();
self.nelts += 1u;
}
/**
* We actually release (turn to none()) the T we're popping so
* that we don't keep anyone's refcount up unexpectedly.
*/
fn pop_front() -> T {
let t: T = get(&self.elts, self.lo);
self.elts.set_elt(self.lo, None);
self.lo = (self.lo + 1u) % self.elts.len();
self.nelts -= 1u;
return t;
}
fn pop_back() -> T {
if self.hi == 0u {
self.hi = self.elts.len() - 1u;
} else { self.hi -= 1u; }
let t: T = get(&self.elts, self.hi);
self.elts.set_elt(self.hi, None);
self.nelts -= 1u;
return t;
}
fn peek_front() -> T { return get(&self.elts, self.lo); }
fn peek_back() -> T { return get(&self.elts, self.hi - 1u); }
fn get(i: int) -> T {
let idx = (self.lo + (i as uint)) % self.elts.len();
return get(&self.elts, idx);
}
}
let repr: Repr<T> = {
mut nelts: 0u,
mut lo: 0u,
mut hi: 0u,
elts:
dvec::from_vec(
vec::from_elem(initial_capacity, None))
};
(move repr) as Deque::<T>
}
#[cfg(test)]
mod tests {
#[legacy_exports];
#[test]
fn test_simple() {
let d: deque::Deque<int> = deque::create::<int>();
assert (d.size() == 0u);
d.add_front(17);
d.add_front(42);
d.add_back(137);
assert (d.size() == 3u);
d.add_back(137);
assert (d.size() == 4u);
log(debug, d.peek_front());
assert (d.peek_front() == 42);
log(debug, d.peek_back());
assert (d.peek_back() == 137);
let mut i: int = d.pop_front();
log(debug, i);
assert (i == 42);
i = d.pop_back();
log(debug, i);
assert (i == 137);
i = d.pop_back();
log(debug, i);
assert (i == 137);
i = d.pop_back();
log(debug, i);
assert (i == 17);
assert (d.size() == 0u);
d.add_back(3);
assert (d.size() == 1u);
d.add_front(2);
assert (d.size() == 2u);
d.add_back(4);
assert (d.size() == 3u);
d.add_front(1);
assert (d.size() == 4u);
log(debug, d.get(0));
log(debug, d.get(1));
log(debug, d.get(2));
log(debug, d.get(3));
assert (d.get(0) == 1);
assert (d.get(1) == 2);
assert (d.get(2) == 3);
assert (d.get(3) == 4);
}
#[test]
fn test_boxes() {
let a: @int = @5;
let b: @int = @72;
let c: @int = @64;
let d: @int = @175;
let deq: deque::Deque<@int> = deque::create::<@int>();
assert (deq.size() == 0u);
deq.add_front(a);
deq.add_front(b);
deq.add_back(c);
assert (deq.size() == 3u);
deq.add_back(d);
assert (deq.size() == 4u);
assert (deq.peek_front() == b);
assert (deq.peek_back() == d);
assert (deq.pop_front() == b);
assert (deq.pop_back() == d);
assert (deq.pop_back() == c);
assert (deq.pop_back() == a);
assert (deq.size() == 0u);
deq.add_back(c);
assert (deq.size() == 1u);
deq.add_front(b);
assert (deq.size() == 2u);
deq.add_back(d);
assert (deq.size() == 3u);
deq.add_front(a);
assert (deq.size() == 4u);
assert (deq.get(0) == a);
assert (deq.get(1) == b);
assert (deq.get(2) == c);
assert (deq.get(3) == d);
}
fn test_parameterized<T: Copy Eq Owned>(+a: T, +b: T, +c: T, +d: T) {
let deq: deque::Deque<T> = deque::create::<T>();
assert (deq.size() == 0u);
deq.add_front(a);
deq.add_front(b);
deq.add_back(c);
assert (deq.size() == 3u);
deq.add_back(d);
assert (deq.size() == 4u);
assert deq.peek_front() == b;
assert deq.peek_back() == d;
assert deq.pop_front() == b;
assert deq.pop_back() == d;
assert deq.pop_back() == c;
assert deq.pop_back() == a;
assert (deq.size() == 0u);
deq.add_back(c);
assert (deq.size() == 1u);
deq.add_front(b);
assert (deq.size() == 2u);
deq.add_back(d);
assert (deq.size() == 3u);
deq.add_front(a);
assert (deq.size() == 4u);
assert deq.get(0) == a;
assert deq.get(1) == b;
assert deq.get(2) == c;
assert deq.get(3) == d;
}
enum Taggy { One(int), Two(int, int), Three(int, int, int), }
enum Taggypar<T> {
Onepar(int), Twopar(int, int), Threepar(int, int, int),
}
type RecCy = {x: int, y: int, t: Taggy};
impl Taggy : Eq {
pure fn eq(other: &Taggy) -> bool {
match self {
One(a1) => match (*other) {
One(b1) => return a1 == b1,
_ => return false
},
Two(a1, a2) => match (*other) {
Two(b1, b2) => return a1 == b1 && a2 == b2,
_ => return false
},
Three(a1, a2, a3) => match (*other) {
Three(b1, b2, b3) => return a1 == b1 && a2 == b2 && a3 == b3,
_ => return false
}
}
}
pure fn ne(other: &Taggy) -> bool { !self.eq(other) }
}
impl Taggypar<int> : Eq {
//let eq4: EqFn<Taggypar<int>> = |x,y| taggypareq::<int>(x, y);
pure fn eq(other: &Taggypar<int>) -> bool {
match self {
Onepar::<int>(a1) => match (*other) {
Onepar::<int>(b1) => return a1 == b1,
_ => return false
},
Twopar::<int>(a1, a2) => match (*other) {
Twopar::<int>(b1, b2) => return a1 == b1 && a2 == b2,
_ => return false
},
Threepar::<int>(a1, a2, a3) => match (*other) {
Threepar::<int>(b1, b2, b3) => {
return a1 == b1 && a2 == b2 && a3 == b3
}
_ => return false
}
}
}
pure fn ne(other: &Taggypar<int>) -> bool { !self.eq(other) }
}
impl RecCy : Eq {
pure fn eq(other: &RecCy) -> bool {
return self.x == (*other).x && self.y == (*other).y &&
self.t == (*other).t;
}
pure fn ne(other: &RecCy) -> bool { !self.eq(other) }
}
#[test]
fn test_param_int() {
test_parameterized::<int>(5, 72, 64, 175);
}
#[test]
fn test_param_at_int() {
test_parameterized::<@int>(@5, @72, @64, @175);
}
#[test]
fn test_param_taggy() {
test_parameterized::<Taggy>(One(1), Two(1, 2), Three(1, 2, 3),
Two(17, 42));
}
#[test]
fn test_param_taggypar() {
test_parameterized::<Taggypar<int>>(Onepar::<int>(1),
Twopar::<int>(1, 2),
Threepar::<int>(1, 2, 3),
Twopar::<int>(17, 42));
}
#[test]
fn test_param_reccy() {
let reccy1: RecCy = {x: 1, y: 2, t: One(1)};
let reccy2: RecCy = {x: 345, y: 2, t: Two(1, 2)};
let reccy3: RecCy = {x: 1, y: 777, t: Three(1, 2, 3)};
let reccy4: RecCy = {x: 19, y: 252, t: Two(17, 42)};
test_parameterized::<RecCy>(reccy1, reccy2, reccy3, reccy4);
}
}