src/libextra/deque.rs - external/github.com/rust-lang/rust - Git at Google

 // Copyright 2012-2013 The Rust Project Developers. See the COPYRIGHT
 // file at the top-level directory of this distribution and at
 // http://rust-lang.org/COPYRIGHT.
 //
 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.

 //! A double-ended queue implemented as a circular buffer
 use core::prelude::*;

 use core::uint;
 use core::util::replace;
 use core::vec;
 use core::cast::transmute;

 static initial_capacity: uint = 32u; // 2^5

 #[allow(missing_doc)]
 pub struct Deque<T> {
     priv nelts: uint,
     priv lo: uint,
     priv hi: uint,
     priv elts: ~[Option<T>]
 }

 impl<T> Container for Deque<T> {
     /// Return the number of elements in the deque
     fn len(&const self) -> uint { self.nelts }

     /// Return true if the deque contains no elements
     fn is_empty(&const self) -> bool { self.len() == 0 }
 }

 impl<T> Mutable for Deque<T> {
     /// Clear the deque, removing all values.
     fn clear(&mut self) {
         for self.elts.mut_iter().advance |x| { *x = None }
         self.nelts = 0;
         self.lo = 0;
         self.hi = 0;
     }
 }

 impl<T> Deque<T> {
     /// Create an empty Deque
     pub fn new() -> Deque<T> {
         Deque{nelts: 0, lo: 0, hi: 0,
               elts: vec::from_fn(initial_capacity, |_| None)}
     }

     /// Return a reference to the first element in the deque
     ///
     /// Fails if the deque is empty
     pub fn peek_front<'a>(&'a self) -> &'a T { get(self.elts, self.lo) }

     /// Return a reference to the last element in the deque
     ///
     /// Fails if the deque is empty
     pub fn peek_back<'a>(&'a self) -> &'a T { get(self.elts, self.hi - 1u) }

     /// Retrieve an element in the deque by index
     ///
     /// Fails if there is no element with the given index
     pub fn get<'a>(&'a self, i: int) -> &'a T {
         let idx = (self.lo + (i as uint)) % self.elts.len();
         get(self.elts, idx)
     }

     /// Iterate over the elements in the deque
     pub fn each(&self, f: &fn(&T) -> bool) -> bool {
         self.eachi(|_i, e| f(e))
     }

     /// Iterate over the elements in the deque by index
     pub fn eachi(&self, f: &fn(uint, &T) -> bool) -> bool {
         uint::range(0, self.nelts, |i| f(i, self.get(i as int)))
     }

     /// Remove and return the first element in the deque
     ///
     /// Fails if the deque is empty
     pub fn pop_front(&mut self) -> T {
         let result = self.elts[self.lo].swap_unwrap();
         self.lo = (self.lo + 1u) % self.elts.len();
         self.nelts -= 1u;
         result
     }

     /// Remove and return the last element in the deque
     ///
     /// Fails if the deque is empty
     pub fn pop_back(&mut self) -> T {
         if self.hi == 0u {
             self.hi = self.elts.len() - 1u;
         } else { self.hi -= 1u; }
         let result = self.elts[self.hi].swap_unwrap();
         self.elts[self.hi] = None;
         self.nelts -= 1u;
         result
     }

     /// Prepend an element to the deque
     pub fn add_front(&mut self, t: T) {
         let oldlo = self.lo;
         if self.lo == 0u {
             self.lo = self.elts.len() - 1u;
         } else { self.lo -= 1u; }
         if self.lo == self.hi {
             self.elts = grow(self.nelts, oldlo, self.elts);
             self.lo = self.elts.len() - 1u;
             self.hi = self.nelts;
         }
         self.elts[self.lo] = Some(t);
         self.nelts += 1u;
     }

     /// Append an element to the deque
     pub fn add_back(&mut self, t: T) {
         if self.lo == self.hi && self.nelts != 0u {
             self.elts = grow(self.nelts, self.lo, self.elts);
             self.lo = 0u;
             self.hi = self.nelts;
         }
         self.elts[self.hi] = Some(t);
         self.hi = (self.hi + 1u) % self.elts.len();
         self.nelts += 1u;
     }

     /// Reserve capacity for exactly `n` elements in the given deque,
     /// doing nothing if `self`'s capacity is already equal to or greater
     /// than the requested capacity
     ///
     /// # Arguments
     ///
     /// * n - The number of elements to reserve space for
     pub fn reserve(&mut self, n: uint) {
         self.elts.reserve(n);
     }

     /// Reserve capacity for at least `n` elements in the given deque,
     /// over-allocating in case the caller needs to reserve additional
     /// space.
     ///
     /// Do nothing if `self`'s capacity is already equal to or greater
     /// than the requested capacity.
     ///
     /// # Arguments
     ///
     /// * n - The number of elements to reserve space for
     pub fn reserve_at_least(&mut self, n: uint) {
         self.elts.reserve_at_least(n);
     }

     /// Front-to-back iterator.
     pub fn iter<'a>(&'a self) -> DequeIterator<'a, T> {
     DequeIterator { idx: self.lo, nelts: self.nelts, used: 0, vec: self.elts }
     }

     /// Front-to-back iterator which returns mutable values.
     pub fn mut_iter<'a>(&'a mut self) -> DequeMutIterator<'a, T> {
     DequeMutIterator { idx: self.lo, nelts: self.nelts, used: 0, vec: self.elts }
     }

     /// Back-to-front iterator.
     pub fn rev_iter<'a>(&'a self) -> DequeRevIterator<'a, T> {
     DequeRevIterator { idx: self.hi - 1u, nelts: self.nelts, used: 0, vec: self.elts }
     }

     /// Back-to-front iterator which returns mutable values.
     pub fn mut_rev_iter<'a>(&'a mut self) -> DequeMutRevIterator<'a, T> {
     DequeMutRevIterator { idx: self.hi - 1u, nelts: self.nelts, used: 0, vec: self.elts }
     }
 }

 macro_rules! iterator {
     (impl $name:ident -> $elem:ty, $step:expr) => {
         impl<'self, T> Iterator<$elem> for $name<'self, T> {
             #[inline]
             fn next(&mut self) -> Option<$elem> {
                 if self.used >= self.nelts {
                     return None;
                 }
                 let ret = unsafe {
                     match self.vec[self.idx % self.vec.len()] {
                         Some(ref e) => Some(transmute(e)),
                         None => None
                     }
                 };
                 self.idx += $step;
                 self.used += 1;
                 ret
             }
         }
     }
 }

 /// Deque iterator
 pub struct DequeIterator<'self, T> {
     priv idx: uint,
     priv nelts: uint,
     priv used: uint,
     priv vec: &'self [Option<T>]
 }
 iterator!{impl DequeIterator -> &'self T, 1}

 /// Deque reverse iterator
 pub struct DequeRevIterator<'self, T> {
     priv idx: uint,
     priv nelts: uint,
     priv used: uint,
     priv vec: &'self [Option<T>]
 }
 iterator!{impl DequeRevIterator -> &'self T, -1}

 /// Deque mutable iterator
 pub struct DequeMutIterator<'self, T> {
     priv idx: uint,
     priv nelts: uint,
     priv used: uint,
     priv vec: &'self mut [Option<T>]

 }
 iterator!{impl DequeMutIterator -> &'self mut T, 1}

 /// Deque mutable reverse iterator
 pub struct DequeMutRevIterator<'self, T> {
     priv idx: uint,
     priv nelts: uint,
     priv used: uint,
     priv vec: &'self mut [Option<T>]
 }
 iterator!{impl DequeMutRevIterator -> &'self mut T, -1}

 /// Grow is only called on full elts, so nelts is also len(elts), unlike
 /// elsewhere.
 fn grow<T>(nelts: uint, lo: uint, elts: &mut [Option<T>]) -> ~[Option<T>] {
     assert_eq!(nelts, elts.len());
     let mut rv = ~[];

     do rv.grow_fn(nelts + 1) |i| {
         replace(&mut elts[(lo + i) % nelts], None)
     }

     rv
 }

 fn get<'r, T>(elts: &'r [Option<T>], i: uint) -> &'r T {
     match elts[i] { Some(ref t) => t, _ => fail!() }
 }

 #[cfg(test)]
 mod tests {
     use super::*;
     use core::cmp::Eq;
     use core::kinds::Copy;
     use core;

     #[test]
     fn test_simple() {
         let mut d = Deque::new();
         assert_eq!(d.len(), 0u);
         d.add_front(17);
         d.add_front(42);
         d.add_back(137);
         assert_eq!(d.len(), 3u);
         d.add_back(137);
         assert_eq!(d.len(), 4u);
         debug!(d.peek_front());
         assert_eq!(*d.peek_front(), 42);
         debug!(d.peek_back());
         assert_eq!(*d.peek_back(), 137);
         let mut i: int = d.pop_front();
         debug!(i);
         assert_eq!(i, 42);
         i = d.pop_back();
         debug!(i);
         assert_eq!(i, 137);
         i = d.pop_back();
         debug!(i);
         assert_eq!(i, 137);
         i = d.pop_back();
         debug!(i);
         assert_eq!(i, 17);
         assert_eq!(d.len(), 0u);
         d.add_back(3);
         assert_eq!(d.len(), 1u);
         d.add_front(2);
         assert_eq!(d.len(), 2u);
         d.add_back(4);
         assert_eq!(d.len(), 3u);
         d.add_front(1);
         assert_eq!(d.len(), 4u);
         debug!(d.get(0));
         debug!(d.get(1));
         debug!(d.get(2));
         debug!(d.get(3));
         assert_eq!(*d.get(0), 1);
         assert_eq!(*d.get(1), 2);
         assert_eq!(*d.get(2), 3);
         assert_eq!(*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 mut deq = Deque::new();
         assert_eq!(deq.len(), 0);
         deq.add_front(a);
         deq.add_front(b);
         deq.add_back(c);
         assert_eq!(deq.len(), 3);
         deq.add_back(d);
         assert_eq!(deq.len(), 4);
         assert_eq!(*deq.peek_front(), b);
         assert_eq!(*deq.peek_back(), d);
         assert_eq!(deq.pop_front(), b);
         assert_eq!(deq.pop_back(), d);
         assert_eq!(deq.pop_back(), c);
         assert_eq!(deq.pop_back(), a);
         assert_eq!(deq.len(), 0);
         deq.add_back(c);
         assert_eq!(deq.len(), 1);
         deq.add_front(b);
         assert_eq!(deq.len(), 2);
         deq.add_back(d);
         assert_eq!(deq.len(), 3);
         deq.add_front(a);
         assert_eq!(deq.len(), 4);
         assert_eq!(*deq.get(0), a);
         assert_eq!(*deq.get(1), b);
         assert_eq!(*deq.get(2), c);
         assert_eq!(*deq.get(3), d);
     }

     #[cfg(test)]
     fn test_parameterized<T:Copy + Eq>(a: T, b: T, c: T, d: T) {
         let mut deq = Deque::new();
         assert_eq!(deq.len(), 0);
         deq.add_front(copy a);
         deq.add_front(copy b);
         deq.add_back(copy c);
         assert_eq!(deq.len(), 3);
         deq.add_back(copy d);
         assert_eq!(deq.len(), 4);
         assert_eq!(copy *deq.peek_front(), copy b);
         assert_eq!(copy *deq.peek_back(), copy d);
         assert_eq!(deq.pop_front(), copy b);
         assert_eq!(deq.pop_back(), copy d);
         assert_eq!(deq.pop_back(), copy c);
         assert_eq!(deq.pop_back(), copy a);
         assert_eq!(deq.len(), 0);
         deq.add_back(copy c);
         assert_eq!(deq.len(), 1);
         deq.add_front(copy b);
         assert_eq!(deq.len(), 2);
         deq.add_back(copy d);
         assert_eq!(deq.len(), 3);
         deq.add_front(copy a);
         assert_eq!(deq.len(), 4);
         assert_eq!(copy *deq.get(0), copy a);
         assert_eq!(copy *deq.get(1), copy b);
         assert_eq!(copy *deq.get(2), copy c);
         assert_eq!(copy *deq.get(3), copy d);
     }

     #[deriving(Eq)]
     enum Taggy { One(int), Two(int, int), Three(int, int, int), }

     #[deriving(Eq)]
     enum Taggypar<T> {
         Onepar(int), Twopar(int, int), Threepar(int, int, int),
     }

     #[deriving(Eq)]
     struct RecCy {
         x: int,
         y: int,
         t: Taggy
     }

     #[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);
     }

     #[test]
     fn test_eachi() {
         let mut deq = Deque::new();
         deq.add_back(1);
         deq.add_back(2);
         deq.add_back(3);

         for deq.eachi |i, e| {
             assert_eq!(*e, i + 1);
         }

         deq.pop_front();

         for deq.eachi |i, e| {
             assert_eq!(*e, i + 2);
         }

     }

     #[test]
     fn test_reserve() {
         let mut d = Deque::new();
         d.add_back(0u64);
         d.reserve(50);
         assert_eq!(d.elts.capacity(), 50);
         let mut d = Deque::new();
         d.add_back(0u32);
         d.reserve(50);
         assert_eq!(d.elts.capacity(), 50);
     }

     #[test]
     fn test_reserve_at_least() {
         let mut d = Deque::new();
         d.add_back(0u64);
         d.reserve_at_least(50);
         assert_eq!(d.elts.capacity(), 64);
         let mut d = Deque::new();
         d.add_back(0u32);
         d.reserve_at_least(50);
         assert_eq!(d.elts.capacity(), 64);
     }

     #[test]
     fn test_iter() {
         let mut d = Deque::new();
         for core::int::range(0,5) |i| {
             d.add_back(i);
         }
         assert_eq!(d.iter().collect::<~[&int]>(), ~[&0,&1,&2,&3,&4]);

         for core::int::range(6,9) |i| {
             d.add_front(i);
         }
         assert_eq!(d.iter().collect::<~[&int]>(), ~[&8,&7,&6,&0,&1,&2,&3,&4]);
     }

     #[test]
     fn test_rev_iter() {
         let mut d = Deque::new();
         for core::int::range(0,5) |i| {
             d.add_back(i);
         }
         assert_eq!(d.rev_iter().collect::<~[&int]>(), ~[&4,&3,&2,&1,&0]);

         for core::int::range(6,9) |i| {
             d.add_front(i);
         }
         assert_eq!(d.rev_iter().collect::<~[&int]>(), ~[&4,&3,&2,&1,&0,&6,&7,&8]);
     }
 }
	// Copyright 2012-2013 The Rust Project Developers. See the COPYRIGHT
	// file at the top-level directory of this distribution and at
	// http://rust-lang.org/COPYRIGHT.
	//
	// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
	// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
	// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
	// option. This file may not be copied, modified, or distributed
	// except according to those terms.

	//! A double-ended queue implemented as a circular buffer
	use core::prelude::*;

	use core::uint;
	use core::util::replace;
	use core::vec;
	use core::cast::transmute;

	static initial_capacity: uint = 32u; // 2^5

	#[allow(missing_doc)]
	pub struct Deque<T> {
	priv nelts: uint,
	priv lo: uint,
	priv hi: uint,
	priv elts: ~[Option<T>]
	}

	impl<T> Container for Deque<T> {
	/// Return the number of elements in the deque
	fn len(&const self) -> uint { self.nelts }

	/// Return true if the deque contains no elements
	fn is_empty(&const self) -> bool { self.len() == 0 }
	}

	impl<T> Mutable for Deque<T> {
	/// Clear the deque, removing all values.
	fn clear(&mut self) {
	for self.elts.mut_iter().advance \|x\| { *x = None }
	self.nelts = 0;
	self.lo = 0;
	self.hi = 0;
	}
	}

	impl<T> Deque<T> {
	/// Create an empty Deque
	pub fn new() -> Deque<T> {
	Deque{nelts: 0, lo: 0, hi: 0,
	elts: vec::from_fn(initial_capacity, \|_\| None)}
	}

	/// Return a reference to the first element in the deque
	///
	/// Fails if the deque is empty
	pub fn peek_front<'a>(&'a self) -> &'a T { get(self.elts, self.lo) }

	/// Return a reference to the last element in the deque
	///
	/// Fails if the deque is empty
	pub fn peek_back<'a>(&'a self) -> &'a T { get(self.elts, self.hi - 1u) }

	/// Retrieve an element in the deque by index
	///
	/// Fails if there is no element with the given index
	pub fn get<'a>(&'a self, i: int) -> &'a T {
	let idx = (self.lo + (i as uint)) % self.elts.len();
	get(self.elts, idx)
	}

	/// Iterate over the elements in the deque
	pub fn each(&self, f: &fn(&T) -> bool) -> bool {
	self.eachi(\|_i, e\| f(e))
	}

	/// Iterate over the elements in the deque by index
	pub fn eachi(&self, f: &fn(uint, &T) -> bool) -> bool {
	uint::range(0, self.nelts, \|i\| f(i, self.get(i as int)))
	}

	/// Remove and return the first element in the deque
	///
	/// Fails if the deque is empty
	pub fn pop_front(&mut self) -> T {
	let result = self.elts[self.lo].swap_unwrap();
	self.lo = (self.lo + 1u) % self.elts.len();
	self.nelts -= 1u;
	result
	}

	/// Remove and return the last element in the deque
	///
	/// Fails if the deque is empty
	pub fn pop_back(&mut self) -> T {
	if self.hi == 0u {
	self.hi = self.elts.len() - 1u;
	} else { self.hi -= 1u; }
	let result = self.elts[self.hi].swap_unwrap();
	self.elts[self.hi] = None;
	self.nelts -= 1u;
	result
	}

	/// Prepend an element to the deque
	pub fn add_front(&mut self, t: T) {
	let oldlo = self.lo;
	if self.lo == 0u {
	self.lo = self.elts.len() - 1u;
	} else { self.lo -= 1u; }
	if self.lo == self.hi {
	self.elts = grow(self.nelts, oldlo, self.elts);
	self.lo = self.elts.len() - 1u;
	self.hi = self.nelts;
	}
	self.elts[self.lo] = Some(t);
	self.nelts += 1u;
	}

	/// Append an element to the deque
	pub fn add_back(&mut self, t: T) {
	if self.lo == self.hi && self.nelts != 0u {
	self.elts = grow(self.nelts, self.lo, self.elts);
	self.lo = 0u;
	self.hi = self.nelts;
	}
	self.elts[self.hi] = Some(t);
	self.hi = (self.hi + 1u) % self.elts.len();
	self.nelts += 1u;
	}

	/// Reserve capacity for exactly `n` elements in the given deque,
	/// doing nothing if `self`'s capacity is already equal to or greater
	/// than the requested capacity
	///
	/// # Arguments
	///
	/// * n - The number of elements to reserve space for
	pub fn reserve(&mut self, n: uint) {
	self.elts.reserve(n);
	}

	/// Reserve capacity for at least `n` elements in the given deque,
	/// over-allocating in case the caller needs to reserve additional
	/// space.
	///
	/// Do nothing if `self`'s capacity is already equal to or greater
	/// than the requested capacity.
	///
	/// # Arguments
	///
	/// * n - The number of elements to reserve space for
	pub fn reserve_at_least(&mut self, n: uint) {
	self.elts.reserve_at_least(n);
	}

	/// Front-to-back iterator.
	pub fn iter<'a>(&'a self) -> DequeIterator<'a, T> {
	DequeIterator { idx: self.lo, nelts: self.nelts, used: 0, vec: self.elts }
	}

	/// Front-to-back iterator which returns mutable values.
	pub fn mut_iter<'a>(&'a mut self) -> DequeMutIterator<'a, T> {
	DequeMutIterator { idx: self.lo, nelts: self.nelts, used: 0, vec: self.elts }
	}

	/// Back-to-front iterator.
	pub fn rev_iter<'a>(&'a self) -> DequeRevIterator<'a, T> {
	DequeRevIterator { idx: self.hi - 1u, nelts: self.nelts, used: 0, vec: self.elts }
	}

	/// Back-to-front iterator which returns mutable values.
	pub fn mut_rev_iter<'a>(&'a mut self) -> DequeMutRevIterator<'a, T> {
	DequeMutRevIterator { idx: self.hi - 1u, nelts: self.nelts, used: 0, vec: self.elts }
	}
	}

	macro_rules! iterator {
	(impl $name:ident -> $elem:ty, $step:expr) => {
	impl<'self, T> Iterator<$elem> for $name<'self, T> {
	#[inline]
	fn next(&mut self) -> Option<$elem> {
	if self.used >= self.nelts {
	return None;
	}
	let ret = unsafe {
	match self.vec[self.idx % self.vec.len()] {
	Some(ref e) => Some(transmute(e)),
	None => None
	}
	};
	self.idx += $step;
	self.used += 1;
	ret
	}
	}
	}
	}

	/// Deque iterator
	pub struct DequeIterator<'self, T> {
	priv idx: uint,
	priv nelts: uint,
	priv used: uint,
	priv vec: &'self [Option<T>]
	}
	iterator!{impl DequeIterator -> &'self T, 1}

	/// Deque reverse iterator
	pub struct DequeRevIterator<'self, T> {
	priv idx: uint,
	priv nelts: uint,
	priv used: uint,
	priv vec: &'self [Option<T>]
	}
	iterator!{impl DequeRevIterator -> &'self T, -1}

	/// Deque mutable iterator
	pub struct DequeMutIterator<'self, T> {
	priv idx: uint,
	priv nelts: uint,
	priv used: uint,
	priv vec: &'self mut [Option<T>]

	}
	iterator!{impl DequeMutIterator -> &'self mut T, 1}

	/// Deque mutable reverse iterator
	pub struct DequeMutRevIterator<'self, T> {
	priv idx: uint,
	priv nelts: uint,
	priv used: uint,
	priv vec: &'self mut [Option<T>]
	}
	iterator!{impl DequeMutRevIterator -> &'self mut T, -1}

	/// Grow is only called on full elts, so nelts is also len(elts), unlike
	/// elsewhere.
	fn grow<T>(nelts: uint, lo: uint, elts: &mut [Option<T>]) -> ~[Option<T>] {
	assert_eq!(nelts, elts.len());
	let mut rv = ~[];

	do rv.grow_fn(nelts + 1) \|i\| {
	replace(&mut elts[(lo + i) % nelts], None)
	}

	rv
	}

	fn get<'r, T>(elts: &'r [Option<T>], i: uint) -> &'r T {
	match elts[i] { Some(ref t) => t, _ => fail!() }
	}

	#[cfg(test)]
	mod tests {
	use super::*;
	use core::cmp::Eq;
	use core::kinds::Copy;
	use core;

	#[test]
	fn test_simple() {
	let mut d = Deque::new();
	assert_eq!(d.len(), 0u);
	d.add_front(17);
	d.add_front(42);
	d.add_back(137);
	assert_eq!(d.len(), 3u);
	d.add_back(137);
	assert_eq!(d.len(), 4u);
	debug!(d.peek_front());
	assert_eq!(*d.peek_front(), 42);
	debug!(d.peek_back());
	assert_eq!(*d.peek_back(), 137);
	let mut i: int = d.pop_front();
	debug!(i);
	assert_eq!(i, 42);
	i = d.pop_back();
	debug!(i);
	assert_eq!(i, 137);
	i = d.pop_back();
	debug!(i);
	assert_eq!(i, 137);
	i = d.pop_back();
	debug!(i);
	assert_eq!(i, 17);
	assert_eq!(d.len(), 0u);
	d.add_back(3);
	assert_eq!(d.len(), 1u);
	d.add_front(2);
	assert_eq!(d.len(), 2u);
	d.add_back(4);
	assert_eq!(d.len(), 3u);
	d.add_front(1);
	assert_eq!(d.len(), 4u);
	debug!(d.get(0));
	debug!(d.get(1));
	debug!(d.get(2));
	debug!(d.get(3));
	assert_eq!(*d.get(0), 1);
	assert_eq!(*d.get(1), 2);
	assert_eq!(*d.get(2), 3);
	assert_eq!(*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 mut deq = Deque::new();
	assert_eq!(deq.len(), 0);
	deq.add_front(a);
	deq.add_front(b);
	deq.add_back(c);
	assert_eq!(deq.len(), 3);
	deq.add_back(d);
	assert_eq!(deq.len(), 4);
	assert_eq!(*deq.peek_front(), b);
	assert_eq!(*deq.peek_back(), d);
	assert_eq!(deq.pop_front(), b);
	assert_eq!(deq.pop_back(), d);
	assert_eq!(deq.pop_back(), c);
	assert_eq!(deq.pop_back(), a);
	assert_eq!(deq.len(), 0);
	deq.add_back(c);
	assert_eq!(deq.len(), 1);
	deq.add_front(b);
	assert_eq!(deq.len(), 2);
	deq.add_back(d);
	assert_eq!(deq.len(), 3);
	deq.add_front(a);
	assert_eq!(deq.len(), 4);
	assert_eq!(*deq.get(0), a);
	assert_eq!(*deq.get(1), b);
	assert_eq!(*deq.get(2), c);
	assert_eq!(*deq.get(3), d);
	}

	#[cfg(test)]
	fn test_parameterized<T:Copy + Eq>(a: T, b: T, c: T, d: T) {
	let mut deq = Deque::new();
	assert_eq!(deq.len(), 0);
	deq.add_front(copy a);
	deq.add_front(copy b);
	deq.add_back(copy c);
	assert_eq!(deq.len(), 3);
	deq.add_back(copy d);
	assert_eq!(deq.len(), 4);
	assert_eq!(copy *deq.peek_front(), copy b);
	assert_eq!(copy *deq.peek_back(), copy d);
	assert_eq!(deq.pop_front(), copy b);
	assert_eq!(deq.pop_back(), copy d);
	assert_eq!(deq.pop_back(), copy c);
	assert_eq!(deq.pop_back(), copy a);
	assert_eq!(deq.len(), 0);
	deq.add_back(copy c);
	assert_eq!(deq.len(), 1);
	deq.add_front(copy b);
	assert_eq!(deq.len(), 2);
	deq.add_back(copy d);
	assert_eq!(deq.len(), 3);
	deq.add_front(copy a);
	assert_eq!(deq.len(), 4);
	assert_eq!(copy *deq.get(0), copy a);
	assert_eq!(copy *deq.get(1), copy b);
	assert_eq!(copy *deq.get(2), copy c);
	assert_eq!(copy *deq.get(3), copy d);
	}

	#[deriving(Eq)]
	enum Taggy { One(int), Two(int, int), Three(int, int, int), }

	#[deriving(Eq)]
	enum Taggypar<T> {
	Onepar(int), Twopar(int, int), Threepar(int, int, int),
	}

	#[deriving(Eq)]
	struct RecCy {
	x: int,
	y: int,
	t: Taggy
	}

	#[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);
	}

	#[test]
	fn test_eachi() {
	let mut deq = Deque::new();
	deq.add_back(1);
	deq.add_back(2);
	deq.add_back(3);

	for deq.eachi \|i, e\| {
	assert_eq!(*e, i + 1);
	}

	deq.pop_front();

	for deq.eachi \|i, e\| {
	assert_eq!(*e, i + 2);
	}

	}

	#[test]
	fn test_reserve() {
	let mut d = Deque::new();
	d.add_back(0u64);
	d.reserve(50);
	assert_eq!(d.elts.capacity(), 50);
	let mut d = Deque::new();
	d.add_back(0u32);
	d.reserve(50);
	assert_eq!(d.elts.capacity(), 50);
	}

	#[test]
	fn test_reserve_at_least() {
	let mut d = Deque::new();
	d.add_back(0u64);
	d.reserve_at_least(50);
	assert_eq!(d.elts.capacity(), 64);
	let mut d = Deque::new();
	d.add_back(0u32);
	d.reserve_at_least(50);
	assert_eq!(d.elts.capacity(), 64);
	}

	#[test]
	fn test_iter() {
	let mut d = Deque::new();
	for core::int::range(0,5) \|i\| {
	d.add_back(i);
	}
	assert_eq!(d.iter().collect::<~[&int]>(), ~[&0,&1,&2,&3,&4]);

	for core::int::range(6,9) \|i\| {
	d.add_front(i);
	}
	assert_eq!(d.iter().collect::<~[&int]>(), ~[&8,&7,&6,&0,&1,&2,&3,&4]);
	}

	#[test]
	fn test_rev_iter() {
	let mut d = Deque::new();
	for core::int::range(0,5) \|i\| {
	d.add_back(i);
	}
	assert_eq!(d.rev_iter().collect::<~[&int]>(), ~[&4,&3,&2,&1,&0]);

	for core::int::range(6,9) \|i\| {
	d.add_front(i);
	}
	assert_eq!(d.rev_iter().collect::<~[&int]>(), ~[&4,&3,&2,&1,&0,&6,&7,&8]);
	}
	}