From 7052371e39268c08067048654a4e115ac86cc51b Mon Sep 17 00:00:00 2001
From: blake2-ppc <blake2-ppc>
Date: Wed, 10 Jul 2013 15:27:14 +0200
Subject: extra: Rename deque::Deque to ringbuf::RingBuf and impl trait Deque

Let RingBuf have a logical name for a concrete type, and Deque is
used for the Deque trait (implemented by RingBuf and dlist).
---
 src/libextra/deque.rs     | 684 --------------------------------------------
 src/libextra/extra.rs     |   2 +-
 src/libextra/ringbuf.rs   | 705 ++++++++++++++++++++++++++++++++++++++++++++++
 src/libextra/serialize.rs |  13 +-
 4 files changed, 713 insertions(+), 691 deletions(-)
 delete mode 100644 src/libextra/deque.rs
 create mode 100644 src/libextra/ringbuf.rs

(limited to 'src/libextra')

diff --git a/src/libextra/deque.rs b/src/libextra/deque.rs
deleted file mode 100644
index 9ce5e2c7ba2..00000000000
--- a/src/libextra/deque.rs
+++ /dev/null
@@ -1,684 +0,0 @@
-// 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 std::num;
-use std::uint;
-use std::vec;
-use std::iterator::FromIterator;
-
-static INITIAL_CAPACITY: uint = 8u; // 2^3
-static MINIMUM_CAPACITY: uint = 2u;
-
-#[allow(missing_doc)]
-#[deriving(Clone)]
-pub struct Deque<T> {
-    priv nelts: uint,
-    priv lo: uint,
-    priv elts: ~[Option<T>]
-}
-
-impl<T> Container for Deque<T> {
-    /// Return the number of elements in the deque
-    fn len(&self) -> uint { self.nelts }
-
-    /// Return true if the deque contains no elements
-    fn is_empty(&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;
-    }
-}
-
-impl<T> Deque<T> {
-    /// Create an empty Deque
-    pub fn new() -> Deque<T> {
-        Deque::with_capacity(INITIAL_CAPACITY)
-    }
-
-    /// Create an empty Deque with space for at least `n` elements.
-    pub fn with_capacity(n: uint) -> Deque<T> {
-        Deque{nelts: 0, lo: 0,
-              elts: vec::from_fn(num::max(MINIMUM_CAPACITY, n), |_| 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.raw_index(0)) }
-
-    /// 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 {
-        if self.nelts > 0 {
-            get(self.elts, self.raw_index(self.nelts - 1))
-        } else {
-            fail!("peek_back: empty deque");
-        }
-    }
-
-    /// 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)
-    }
-
-    /// 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
-    }
-
-    /// Return index in underlying vec for a given logical element index
-    fn raw_index(&self, idx: uint) -> uint {
-        raw_index(self.lo, self.elts.len(), idx)
-    }
-
-    /// Remove and return the last element in the deque
-    ///
-    /// Fails if the deque is empty
-    pub fn pop_back(&mut self) -> T {
-        self.nelts -= 1;
-        let hi = self.raw_index(self.nelts);
-        self.elts[hi].swap_unwrap()
-    }
-
-    /// Prepend an element to the deque
-    pub fn add_front(&mut self, t: T) {
-        if self.nelts == self.elts.len() {
-            grow(self.nelts, &mut self.lo, &mut self.elts);
-        }
-        if self.lo == 0u {
-            self.lo = self.elts.len() - 1u;
-        } else { self.lo -= 1u; }
-        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.nelts == self.elts.len() {
-            grow(self.nelts, &mut self.lo, &mut self.elts);
-        }
-        let hi = self.raw_index(self.nelts);
-        self.elts[hi] = Some(t);
-        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{index: 0, nelts: self.nelts, elts: self.elts, lo: self.lo}
-    }
-
-    /// Front-to-back iterator which returns mutable values.
-    pub fn mut_iter<'a>(&'a mut self) -> DequeMutIterator<'a, T> {
-        DequeMutIterator{index: 0, nelts: self.nelts, elts: self.elts, lo: self.lo}
-    }
-
-    /// Back-to-front iterator.
-    pub fn rev_iter<'a>(&'a self) -> DequeRevIterator<'a, T> {
-        DequeRevIterator{index: self.nelts-1, nelts: self.nelts, elts: self.elts,
-                         lo: self.lo}
-    }
-
-    /// Back-to-front iterator which returns mutable values.
-    pub fn mut_rev_iter<'a>(&'a mut self) -> DequeMutRevIterator<'a, T> {
-        DequeMutRevIterator{index: self.nelts-1, nelts: self.nelts, elts: self.elts,
-                            lo: self.lo}
-    }
-}
-
-macro_rules! iterator {
-    (impl $name:ident -> $elem:ty, $getter:ident, $step:expr) => {
-        impl<'self, T> Iterator<$elem> for $name<'self, T> {
-            #[inline]
-            fn next(&mut self) -> Option<$elem> {
-                if self.nelts == 0 {
-                    return None;
-                }
-                let raw_index = raw_index(self.lo, self.elts.len(), self.index);
-                self.index += $step;
-                self.nelts -= 1;
-                Some(self.elts[raw_index]. $getter ())
-            }
-        }
-    }
-}
-
-/// Deque iterator
-pub struct DequeIterator<'self, T> {
-    priv lo: uint,
-    priv nelts: uint,
-    priv index: uint,
-    priv elts: &'self [Option<T>],
-}
-iterator!{impl DequeIterator -> &'self T, get_ref, 1}
-
-/// Deque reverse iterator
-pub struct DequeRevIterator<'self, T> {
-    priv lo: uint,
-    priv nelts: uint,
-    priv index: uint,
-    priv elts: &'self [Option<T>],
-}
-iterator!{impl DequeRevIterator -> &'self T, get_ref, -1}
-
-/// Deque mutable iterator
-pub struct DequeMutIterator<'self, T> {
-    priv lo: uint,
-    priv nelts: uint,
-    priv index: uint,
-    priv elts: &'self mut [Option<T>],
-}
-iterator!{impl DequeMutIterator -> &'self mut T, get_mut_ref, 1}
-
-/// Deque mutable reverse iterator
-pub struct DequeMutRevIterator<'self, T> {
-    priv lo: uint,
-    priv nelts: uint,
-    priv index: uint,
-    priv elts: &'self mut [Option<T>],
-}
-iterator!{impl DequeMutRevIterator -> &'self mut T, get_mut_ref, -1}
-
-/// Grow is only called on full elts, so nelts is also len(elts), unlike
-/// elsewhere.
-fn grow<T>(nelts: uint, loptr: &mut uint, elts: &mut ~[Option<T>]) {
-    assert_eq!(nelts, elts.len());
-    let lo = *loptr;
-    let newlen = nelts * 2;
-    elts.reserve(newlen);
-
-    /* fill with None */
-    for uint::range(elts.len(), elts.capacity()) |_| {
-        elts.push(None);
-    }
-
-    /*
-      Move the shortest half into the newly reserved area.
-      lo ---->|
-      nelts ----------->|
-        [o o o|o o o o o]
-      A [. . .|o o o o o o o o|. . . . .]
-      B [o o o|. . . . . . . .|o o o o o]
-     */
-
-    assert!(newlen - nelts/2 >= nelts);
-    if lo <= (nelts - lo) { // A
-        for uint::range(0, lo) |i| {
-            elts.swap(i, nelts + i);
-        }
-    } else {                // B
-        for uint::range(lo, nelts) |i| {
-            elts.swap(i, newlen - nelts + i);
-        }
-        *loptr += newlen - nelts;
-    }
-}
-
-fn get<'r, T>(elts: &'r [Option<T>], i: uint) -> &'r T {
-    match elts[i] { Some(ref t) => t, _ => fail!() }
-}
-
-/// Return index in underlying vec for a given logical element index
-fn raw_index(lo: uint, len: uint, index: uint) -> uint {
-    if lo >= len - index {
-        lo + index - len
-    } else {
-        lo + index
-    }
-}
-
-impl<A: Eq> Eq for Deque<A> {
-    fn eq(&self, other: &Deque<A>) -> bool {
-        self.nelts == other.nelts &&
-            self.iter().zip(other.iter()).all(|(a, b)| a.eq(b))
-    }
-    fn ne(&self, other: &Deque<A>) -> bool {
-        !self.eq(other)
-    }
-}
-
-impl<A, T: Iterator<A>> FromIterator<A, T> for Deque<A> {
-    fn from_iterator(iterator: &mut T) -> Deque<A> {
-        let mut deq = Deque::new();
-        for iterator.advance |elt| {
-            deq.add_back(elt);
-        }
-        deq
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use std::cmp::Eq;
-    use std::kinds::Copy;
-    use std::{int, uint};
-    use extra::test;
-
-    #[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);
-    }
-
-    #[test]
-    fn test_add_front_grow() {
-        let mut deq = Deque::new();
-        for int::range(0, 66) |i| {
-            deq.add_front(i);
-        }
-        assert_eq!(deq.len(), 66);
-
-        for int::range(0, 66) |i| {
-            assert_eq!(*deq.get(i), 65 - i);
-        }
-
-        let mut deq = Deque::new();
-        for int::range(0, 66) |i| {
-            deq.add_back(i);
-        }
-
-        for int::range(0, 66) |i| {
-            assert_eq!(*deq.get(i), i);
-        }
-    }
-
-    #[bench]
-    fn bench_new(b: &mut test::BenchHarness) {
-        do b.iter {
-            let _ = Deque::new::<u64>();
-        }
-    }
-
-    #[bench]
-    fn bench_add_back(b: &mut test::BenchHarness) {
-        let mut deq = Deque::new();
-        do b.iter {
-            deq.add_back(0);
-        }
-    }
-
-    #[bench]
-    fn bench_add_front(b: &mut test::BenchHarness) {
-        let mut deq = Deque::new();
-        do b.iter {
-            deq.add_front(0);
-        }
-    }
-
-    #[bench]
-    fn bench_grow(b: &mut test::BenchHarness) {
-        let mut deq = Deque::new();
-        do b.iter {
-            for 65.times {
-                deq.add_front(1);
-            }
-        }
-    }
-
-    #[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_with_capacity() {
-        let mut d = Deque::with_capacity(0);
-        d.add_back(1);
-        assert_eq!(d.len(), 1);
-        let mut d = Deque::with_capacity(50);
-        d.add_back(1);
-        assert_eq!(d.len(), 1);
-    }
-
-    #[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();
-        assert_eq!(d.iter().next(), None);
-
-        for int::range(0,5) |i| {
-            d.add_back(i);
-        }
-        assert_eq!(d.iter().collect::<~[&int]>(), ~[&0,&1,&2,&3,&4]);
-
-        for 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();
-        assert_eq!(d.rev_iter().next(), None);
-
-        for int::range(0,5) |i| {
-            d.add_back(i);
-        }
-        assert_eq!(d.rev_iter().collect::<~[&int]>(), ~[&4,&3,&2,&1,&0]);
-
-        for int::range(6,9) |i| {
-            d.add_front(i);
-        }
-        assert_eq!(d.rev_iter().collect::<~[&int]>(), ~[&4,&3,&2,&1,&0,&6,&7,&8]);
-    }
-
-    #[test]
-    fn test_mut_iter() {
-        let mut d = Deque::new();
-        assert!(d.mut_iter().next().is_none());
-
-        for uint::range(0,3) |i| {
-            d.add_front(i);
-        }
-
-        for d.mut_iter().enumerate().advance |(i, elt)| {
-            assert_eq!(*elt, 2 - i);
-            *elt = i;
-        }
-
-        {
-            let mut it = d.mut_iter();
-            assert_eq!(*it.next().unwrap(), 0);
-            assert_eq!(*it.next().unwrap(), 1);
-            assert_eq!(*it.next().unwrap(), 2);
-            assert!(it.next().is_none());
-        }
-    }
-
-    #[test]
-    fn test_mut_rev_iter() {
-        let mut d = Deque::new();
-        assert!(d.mut_rev_iter().next().is_none());
-
-        for uint::range(0,3) |i| {
-            d.add_front(i);
-        }
-
-        for d.mut_rev_iter().enumerate().advance |(i, elt)| {
-            assert_eq!(*elt, i);
-            *elt = i;
-        }
-
-        {
-            let mut it = d.mut_rev_iter();
-            assert_eq!(*it.next().unwrap(), 0);
-            assert_eq!(*it.next().unwrap(), 1);
-            assert_eq!(*it.next().unwrap(), 2);
-            assert!(it.next().is_none());
-        }
-    }
-
-    #[test]
-    fn test_from_iterator() {
-        use std::iterator;
-        let v = ~[1,2,3,4,5,6,7];
-        let deq: Deque<int> = v.iter().transform(|&x| x).collect();
-        let u: ~[int] = deq.iter().transform(|&x| x).collect();
-        assert_eq!(u, v);
-
-        let mut seq = iterator::Counter::new(0u, 2).take_(256);
-        let deq: Deque<uint> = seq.collect();
-        for deq.iter().enumerate().advance |(i, &x)| {
-            assert_eq!(2*i, x);
-        }
-        assert_eq!(deq.len(), 256);
-    }
-
-    #[test]
-    fn test_clone() {
-        let mut d = Deque::new();
-        d.add_front(17);
-        d.add_front(42);
-        d.add_back(137);
-        d.add_back(137);
-        assert_eq!(d.len(), 4u);
-        let mut e = d.clone();
-        assert_eq!(e.len(), 4u);
-        while !d.is_empty() {
-            assert_eq!(d.pop_back(), e.pop_back());
-        }
-        assert_eq!(d.len(), 0u);
-        assert_eq!(e.len(), 0u);
-    }
-
-    #[test]
-    fn test_eq() {
-        let mut d = Deque::new();
-        assert_eq!(&d, &Deque::with_capacity(0));
-        d.add_front(137);
-        d.add_front(17);
-        d.add_front(42);
-        d.add_back(137);
-        let mut e = Deque::with_capacity(0);
-        e.add_back(42);
-        e.add_back(17);
-        e.add_back(137);
-        e.add_back(137);
-        assert_eq!(&e, &d);
-        e.pop_back();
-        e.add_back(0);
-        assert!(e != d);
-        e.clear();
-        assert_eq!(e, Deque::new());
-    }
-}
diff --git a/src/libextra/extra.rs b/src/libextra/extra.rs
index 18322fcda59..66ee52f53db 100644
--- a/src/libextra/extra.rs
+++ b/src/libextra/extra.rs
@@ -69,9 +69,9 @@ pub mod flatpipes;
 
 pub mod container;
 pub mod bitv;
-pub mod deque;
 pub mod fun_treemap;
 pub mod list;
+pub mod ringbuf;
 pub mod priority_queue;
 pub mod smallintmap;
 
diff --git a/src/libextra/ringbuf.rs b/src/libextra/ringbuf.rs
new file mode 100644
index 00000000000..28eab9d9012
--- /dev/null
+++ b/src/libextra/ringbuf.rs
@@ -0,0 +1,705 @@
+// 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 std::num;
+use std::util;
+use std::uint;
+use std::vec;
+use std::iterator::FromIterator;
+
+use container::Deque;
+
+static INITIAL_CAPACITY: uint = 8u; // 2^3
+static MINIMUM_CAPACITY: uint = 2u;
+
+#[allow(missing_doc)]
+#[deriving(Clone)]
+pub struct RingBuf<T> {
+    priv nelts: uint,
+    priv lo: uint,
+    priv elts: ~[Option<T>]
+}
+
+impl<T> Container for RingBuf<T> {
+    /// Return the number of elements in the RingBuf
+    fn len(&self) -> uint { self.nelts }
+
+    /// Return true if the RingBufcontains no elements
+    fn is_empty(&self) -> bool { self.len() == 0 }
+}
+
+impl<T> Mutable for RingBuf<T> {
+    /// Clear the RingBuf, removing all values.
+    fn clear(&mut self) {
+        for self.elts.mut_iter().advance |x| { *x = None }
+        self.nelts = 0;
+        self.lo = 0;
+    }
+}
+
+impl<T> Deque<T> for RingBuf<T> {
+    /// Return a reference to the first element in the RingBuf
+    fn front<'a>(&'a self) -> Option<&'a T> {
+        if self.nelts > 0 { Some(self.get(0)) } else { None }
+    }
+
+    /// Return a mutable reference to the first element in the RingBuf
+    fn front_mut<'a>(&'a mut self) -> Option<&'a mut T> {
+        if self.nelts > 0 { Some(self.get_mut(0)) } else { None }
+    }
+
+    /// Return a reference to the last element in the RingBuf
+    fn back<'a>(&'a self) -> Option<&'a T> {
+        if self.nelts > 0 { Some(self.get(self.nelts - 1)) } else { None }
+    }
+
+    /// Return a mutable reference to the last element in the RingBuf
+    fn back_mut<'a>(&'a mut self) -> Option<&'a mut T> {
+        if self.nelts > 0 { Some(self.get_mut(self.nelts - 1)) } else { None }
+    }
+
+    /// Remove and return the first element in the RingBuf, or None if it is empty
+    fn pop_front(&mut self) -> Option<T> {
+        let result = util::replace(&mut self.elts[self.lo], None);
+        if result.is_some() {
+            self.lo = (self.lo + 1u) % self.elts.len();
+            self.nelts -= 1u;
+        }
+        result
+    }
+
+    /// Remove and return the last element in the RingBuf, or None if it is empty
+    fn pop_back(&mut self) -> Option<T> {
+        if self.nelts > 0 {
+            self.nelts -= 1;
+            let hi = self.raw_index(self.nelts);
+            util::replace(&mut self.elts[hi], None)
+        } else {
+            None
+        }
+    }
+
+    /// Prepend an element to the RingBuf
+    fn push_front(&mut self, t: T) {
+        if self.nelts == self.elts.len() {
+            grow(self.nelts, &mut self.lo, &mut self.elts);
+        }
+        if self.lo == 0u {
+            self.lo = self.elts.len() - 1u;
+        } else { self.lo -= 1u; }
+        self.elts[self.lo] = Some(t);
+        self.nelts += 1u;
+    }
+
+    /// Append an element to the RingBuf
+    fn push_back(&mut self, t: T) {
+        if self.nelts == self.elts.len() {
+            grow(self.nelts, &mut self.lo, &mut self.elts);
+        }
+        let hi = self.raw_index(self.nelts);
+        self.elts[hi] = Some(t);
+        self.nelts += 1u;
+    }
+}
+
+impl<T> RingBuf<T> {
+    /// Create an empty RingBuf
+    pub fn new() -> RingBuf<T> {
+        RingBuf::with_capacity(INITIAL_CAPACITY)
+    }
+
+    /// Create an empty RingBuf with space for at least `n` elements.
+    pub fn with_capacity(n: uint) -> RingBuf<T> {
+        RingBuf{nelts: 0, lo: 0,
+              elts: vec::from_fn(num::max(MINIMUM_CAPACITY, n), |_| None)}
+    }
+
+    /// Retrieve an element in the RingBuf by index
+    ///
+    /// Fails if there is no element with the given index
+    pub fn get<'a>(&'a self, i: uint) -> &'a T {
+        let idx = self.raw_index(i);
+        match self.elts[idx] {
+            None => fail!(),
+            Some(ref v) => v
+        }
+    }
+
+    /// Retrieve an element in the RingBuf by index
+    ///
+    /// Fails if there is no element with the given index
+    pub fn get_mut<'a>(&'a mut self, i: uint) -> &'a mut T {
+        let idx = self.raw_index(i);
+        match self.elts[idx] {
+            None => fail!(),
+            Some(ref mut v) => v
+        }
+    }
+
+    /// Return index in underlying vec for a given logical element index
+    fn raw_index(&self, idx: uint) -> uint {
+        raw_index(self.lo, self.elts.len(), idx)
+    }
+
+    /// Reserve capacity for exactly `n` elements in the given RingBuf,
+    /// 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 RingBuf,
+    /// 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) -> RingBufIterator<'a, T> {
+        RingBufIterator{index: 0, nelts: self.nelts, elts: self.elts, lo: self.lo}
+    }
+
+    /// Front-to-back iterator which returns mutable values.
+    pub fn mut_iter<'a>(&'a mut self) -> RingBufMutIterator<'a, T> {
+        RingBufMutIterator{index: 0, nelts: self.nelts, elts: self.elts, lo: self.lo}
+    }
+
+    /// Back-to-front iterator.
+    pub fn rev_iter<'a>(&'a self) -> RingBufRevIterator<'a, T> {
+        RingBufRevIterator{index: self.nelts-1, nelts: self.nelts, elts: self.elts,
+                         lo: self.lo}
+    }
+
+    /// Back-to-front iterator which returns mutable values.
+    pub fn mut_rev_iter<'a>(&'a mut self) -> RingBufMutRevIterator<'a, T> {
+        RingBufMutRevIterator{index: self.nelts-1, nelts: self.nelts, elts: self.elts,
+                            lo: self.lo}
+    }
+}
+
+macro_rules! iterator {
+    (impl $name:ident -> $elem:ty, $getter:ident, $step:expr) => {
+        impl<'self, T> Iterator<$elem> for $name<'self, T> {
+            #[inline]
+            fn next(&mut self) -> Option<$elem> {
+                if self.nelts == 0 {
+                    return None;
+                }
+                let raw_index = raw_index(self.lo, self.elts.len(), self.index);
+                self.index += $step;
+                self.nelts -= 1;
+                Some(self.elts[raw_index]. $getter ())
+            }
+        }
+    }
+}
+
+/// RingBuf iterator
+pub struct RingBufIterator<'self, T> {
+    priv lo: uint,
+    priv nelts: uint,
+    priv index: uint,
+    priv elts: &'self [Option<T>],
+}
+iterator!{impl RingBufIterator -> &'self T, get_ref, 1}
+
+/// RingBuf reverse iterator
+pub struct RingBufRevIterator<'self, T> {
+    priv lo: uint,
+    priv nelts: uint,
+    priv index: uint,
+    priv elts: &'self [Option<T>],
+}
+iterator!{impl RingBufRevIterator -> &'self T, get_ref, -1}
+
+/// RingBuf mutable iterator
+pub struct RingBufMutIterator<'self, T> {
+    priv lo: uint,
+    priv nelts: uint,
+    priv index: uint,
+    priv elts: &'self mut [Option<T>],
+}
+iterator!{impl RingBufMutIterator -> &'self mut T, get_mut_ref, 1}
+
+/// RingBuf mutable reverse iterator
+pub struct RingBufMutRevIterator<'self, T> {
+    priv lo: uint,
+    priv nelts: uint,
+    priv index: uint,
+    priv elts: &'self mut [Option<T>],
+}
+iterator!{impl RingBufMutRevIterator -> &'self mut T, get_mut_ref, -1}
+
+/// Grow is only called on full elts, so nelts is also len(elts), unlike
+/// elsewhere.
+fn grow<T>(nelts: uint, loptr: &mut uint, elts: &mut ~[Option<T>]) {
+    assert_eq!(nelts, elts.len());
+    let lo = *loptr;
+    let newlen = nelts * 2;
+    elts.reserve(newlen);
+
+    /* fill with None */
+    for uint::range(elts.len(), elts.capacity()) |_| {
+        elts.push(None);
+    }
+
+    /*
+      Move the shortest half into the newly reserved area.
+      lo ---->|
+      nelts ----------->|
+        [o o o|o o o o o]
+      A [. . .|o o o o o o o o|. . . . .]
+      B [o o o|. . . . . . . .|o o o o o]
+     */
+
+    assert!(newlen - nelts/2 >= nelts);
+    if lo <= (nelts - lo) { // A
+        for uint::range(0, lo) |i| {
+            elts.swap(i, nelts + i);
+        }
+    } else {                // B
+        for uint::range(lo, nelts) |i| {
+            elts.swap(i, newlen - nelts + i);
+        }
+        *loptr += newlen - nelts;
+    }
+}
+
+/// Return index in underlying vec for a given logical element index
+fn raw_index(lo: uint, len: uint, index: uint) -> uint {
+    if lo >= len - index {
+        lo + index - len
+    } else {
+        lo + index
+    }
+}
+
+impl<A: Eq> Eq for RingBuf<A> {
+    fn eq(&self, other: &RingBuf<A>) -> bool {
+        self.nelts == other.nelts &&
+            self.iter().zip(other.iter()).all(|(a, b)| a.eq(b))
+    }
+    fn ne(&self, other: &RingBuf<A>) -> bool {
+        !self.eq(other)
+    }
+}
+
+impl<A, T: Iterator<A>> FromIterator<A, T> for RingBuf<A> {
+    fn from_iterator(iterator: &mut T) -> RingBuf<A> {
+        let mut deq = RingBuf::new();
+        for iterator.advance |elt| {
+            deq.push_back(elt);
+        }
+        deq
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::cmp::Eq;
+    use std::kinds::Copy;
+    use std::{int, uint};
+    use extra::test;
+
+    #[test]
+    fn test_simple() {
+        let mut d = RingBuf::new();
+        assert_eq!(d.len(), 0u);
+        d.push_front(17);
+        d.push_front(42);
+        d.push_back(137);
+        assert_eq!(d.len(), 3u);
+        d.push_back(137);
+        assert_eq!(d.len(), 4u);
+        debug!(d.front());
+        assert_eq!(*d.front().unwrap(), 42);
+        debug!(d.back());
+        assert_eq!(*d.back().unwrap(), 137);
+        let mut i = d.pop_front();
+        debug!(i);
+        assert_eq!(i, Some(42));
+        i = d.pop_back();
+        debug!(i);
+        assert_eq!(i, Some(137));
+        i = d.pop_back();
+        debug!(i);
+        assert_eq!(i, Some(137));
+        i = d.pop_back();
+        debug!(i);
+        assert_eq!(i, Some(17));
+        assert_eq!(d.len(), 0u);
+        d.push_back(3);
+        assert_eq!(d.len(), 1u);
+        d.push_front(2);
+        assert_eq!(d.len(), 2u);
+        d.push_back(4);
+        assert_eq!(d.len(), 3u);
+        d.push_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 = RingBuf::new();
+        assert_eq!(deq.len(), 0);
+        deq.push_front(a);
+        deq.push_front(b);
+        deq.push_back(c);
+        assert_eq!(deq.len(), 3);
+        deq.push_back(d);
+        assert_eq!(deq.len(), 4);
+        assert_eq!(deq.front(), Some(&b));
+        assert_eq!(deq.back(), Some(&d));
+        assert_eq!(deq.pop_front(), Some(b));
+        assert_eq!(deq.pop_back(), Some(d));
+        assert_eq!(deq.pop_back(), Some(c));
+        assert_eq!(deq.pop_back(), Some(a));
+        assert_eq!(deq.len(), 0);
+        deq.push_back(c);
+        assert_eq!(deq.len(), 1);
+        deq.push_front(b);
+        assert_eq!(deq.len(), 2);
+        deq.push_back(d);
+        assert_eq!(deq.len(), 3);
+        deq.push_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 = RingBuf::new();
+        assert_eq!(deq.len(), 0);
+        deq.push_front(copy a);
+        deq.push_front(copy b);
+        deq.push_back(copy c);
+        assert_eq!(deq.len(), 3);
+        deq.push_back(copy d);
+        assert_eq!(deq.len(), 4);
+        assert_eq!(deq.front(), Some(&b));
+        assert_eq!(deq.back(), Some(&d));
+        assert_eq!(deq.pop_front(), Some(copy b));
+        assert_eq!(deq.pop_back(), Some(copy d));
+        assert_eq!(deq.pop_back(), Some(copy c));
+        assert_eq!(deq.pop_back(), Some(copy a));
+        assert_eq!(deq.len(), 0);
+        deq.push_back(copy c);
+        assert_eq!(deq.len(), 1);
+        deq.push_front(copy b);
+        assert_eq!(deq.len(), 2);
+        deq.push_back(copy d);
+        assert_eq!(deq.len(), 3);
+        deq.push_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);
+    }
+
+    #[test]
+    fn test_push_front_grow() {
+        let mut deq = RingBuf::new();
+        for uint::range(0, 66) |i| {
+            deq.push_front(i);
+        }
+        assert_eq!(deq.len(), 66);
+
+        for uint::range(0, 66) |i| {
+            assert_eq!(*deq.get(i), 65 - i);
+        }
+
+        let mut deq = RingBuf::new();
+        for uint::range(0, 66) |i| {
+            deq.push_back(i);
+        }
+
+        for uint::range(0, 66) |i| {
+            assert_eq!(*deq.get(i), i);
+        }
+    }
+
+    #[bench]
+    fn bench_new(b: &mut test::BenchHarness) {
+        do b.iter {
+            let _ = RingBuf::new::<u64>();
+        }
+    }
+
+    #[bench]
+    fn bench_push_back(b: &mut test::BenchHarness) {
+        let mut deq = RingBuf::new();
+        do b.iter {
+            deq.push_back(0);
+        }
+    }
+
+    #[bench]
+    fn bench_push_front(b: &mut test::BenchHarness) {
+        let mut deq = RingBuf::new();
+        do b.iter {
+            deq.push_front(0);
+        }
+    }
+
+    #[bench]
+    fn bench_grow(b: &mut test::BenchHarness) {
+        let mut deq = RingBuf::new();
+        do b.iter {
+            for 65.times {
+                deq.push_front(1);
+            }
+        }
+    }
+
+    #[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_with_capacity() {
+        let mut d = RingBuf::with_capacity(0);
+        d.push_back(1);
+        assert_eq!(d.len(), 1);
+        let mut d = RingBuf::with_capacity(50);
+        d.push_back(1);
+        assert_eq!(d.len(), 1);
+    }
+
+    #[test]
+    fn test_reserve() {
+        let mut d = RingBuf::new();
+        d.push_back(0u64);
+        d.reserve(50);
+        assert_eq!(d.elts.capacity(), 50);
+        let mut d = RingBuf::new();
+        d.push_back(0u32);
+        d.reserve(50);
+        assert_eq!(d.elts.capacity(), 50);
+    }
+
+    #[test]
+    fn test_reserve_at_least() {
+        let mut d = RingBuf::new();
+        d.push_back(0u64);
+        d.reserve_at_least(50);
+        assert_eq!(d.elts.capacity(), 64);
+        let mut d = RingBuf::new();
+        d.push_back(0u32);
+        d.reserve_at_least(50);
+        assert_eq!(d.elts.capacity(), 64);
+    }
+
+    #[test]
+    fn test_iter() {
+        let mut d = RingBuf::new();
+        assert_eq!(d.iter().next(), None);
+
+        for int::range(0,5) |i| {
+            d.push_back(i);
+        }
+        assert_eq!(d.iter().collect::<~[&int]>(), ~[&0,&1,&2,&3,&4]);
+
+        for int::range(6,9) |i| {
+            d.push_front(i);
+        }
+        assert_eq!(d.iter().collect::<~[&int]>(), ~[&8,&7,&6,&0,&1,&2,&3,&4]);
+    }
+
+    #[test]
+    fn test_rev_iter() {
+        let mut d = RingBuf::new();
+        assert_eq!(d.rev_iter().next(), None);
+
+        for int::range(0,5) |i| {
+            d.push_back(i);
+        }
+        assert_eq!(d.rev_iter().collect::<~[&int]>(), ~[&4,&3,&2,&1,&0]);
+
+        for int::range(6,9) |i| {
+            d.push_front(i);
+        }
+        assert_eq!(d.rev_iter().collect::<~[&int]>(), ~[&4,&3,&2,&1,&0,&6,&7,&8]);
+    }
+
+    #[test]
+    fn test_mut_iter() {
+        let mut d = RingBuf::new();
+        assert!(d.mut_iter().next().is_none());
+
+        for uint::range(0,3) |i| {
+            d.push_front(i);
+        }
+
+        for d.mut_iter().enumerate().advance |(i, elt)| {
+            assert_eq!(*elt, 2 - i);
+            *elt = i;
+        }
+
+        {
+            let mut it = d.mut_iter();
+            assert_eq!(*it.next().unwrap(), 0);
+            assert_eq!(*it.next().unwrap(), 1);
+            assert_eq!(*it.next().unwrap(), 2);
+            assert!(it.next().is_none());
+        }
+    }
+
+    #[test]
+    fn test_mut_rev_iter() {
+        let mut d = RingBuf::new();
+        assert!(d.mut_rev_iter().next().is_none());
+
+        for uint::range(0,3) |i| {
+            d.push_front(i);
+        }
+
+        for d.mut_rev_iter().enumerate().advance |(i, elt)| {
+            assert_eq!(*elt, i);
+            *elt = i;
+        }
+
+        {
+            let mut it = d.mut_rev_iter();
+            assert_eq!(*it.next().unwrap(), 0);
+            assert_eq!(*it.next().unwrap(), 1);
+            assert_eq!(*it.next().unwrap(), 2);
+            assert!(it.next().is_none());
+        }
+    }
+
+    #[test]
+    fn test_from_iterator() {
+        use std::iterator;
+        let v = ~[1,2,3,4,5,6,7];
+        let deq: RingBuf<int> = v.iter().transform(|&x| x).collect();
+        let u: ~[int] = deq.iter().transform(|&x| x).collect();
+        assert_eq!(u, v);
+
+        let mut seq = iterator::Counter::new(0u, 2).take_(256);
+        let deq: RingBuf<uint> = seq.collect();
+        for deq.iter().enumerate().advance |(i, &x)| {
+            assert_eq!(2*i, x);
+        }
+        assert_eq!(deq.len(), 256);
+    }
+
+    #[test]
+    fn test_clone() {
+        let mut d = RingBuf::new();
+        d.push_front(17);
+        d.push_front(42);
+        d.push_back(137);
+        d.push_back(137);
+        assert_eq!(d.len(), 4u);
+        let mut e = d.clone();
+        assert_eq!(e.len(), 4u);
+        while !d.is_empty() {
+            assert_eq!(d.pop_back(), e.pop_back());
+        }
+        assert_eq!(d.len(), 0u);
+        assert_eq!(e.len(), 0u);
+    }
+
+    #[test]
+    fn test_eq() {
+        let mut d = RingBuf::new();
+        assert_eq!(&d, &RingBuf::with_capacity(0));
+        d.push_front(137);
+        d.push_front(17);
+        d.push_front(42);
+        d.push_back(137);
+        let mut e = RingBuf::with_capacity(0);
+        e.push_back(42);
+        e.push_back(17);
+        e.push_back(137);
+        e.push_back(137);
+        assert_eq!(&e, &d);
+        e.pop_back();
+        e.push_back(0);
+        assert!(e != d);
+        e.clear();
+        assert_eq!(e, RingBuf::new());
+    }
+}
diff --git a/src/libextra/serialize.rs b/src/libextra/serialize.rs
index 5a9072a68d8..f185f7d7321 100644
--- a/src/libextra/serialize.rs
+++ b/src/libextra/serialize.rs
@@ -23,7 +23,8 @@ use std::hashmap::{HashMap, HashSet};
 use std::trie::{TrieMap, TrieSet};
 use std::uint;
 use std::vec;
-use deque::Deque;
+use ringbuf::RingBuf;
+use container::Deque;
 use dlist::List;
 use treemap::{TreeMap, TreeSet};
 
@@ -679,7 +680,7 @@ impl<D:Decoder,T:Decodable<D>> Decodable<D> for List<T> {
 impl<
     S: Encoder,
     T: Encodable<S>
-> Encodable<S> for Deque<T> {
+> Encodable<S> for RingBuf<T> {
     fn encode(&self, s: &mut S) {
         do s.emit_seq(self.len()) |s| {
             for self.iter().enumerate().advance |(i, e)| {
@@ -689,12 +690,12 @@ impl<
     }
 }
 
-impl<D:Decoder,T:Decodable<D>> Decodable<D> for Deque<T> {
-    fn decode(d: &mut D) -> Deque<T> {
-        let mut deque = Deque::new();
+impl<D:Decoder,T:Decodable<D>> Decodable<D> for RingBuf<T> {
+    fn decode(d: &mut D) -> RingBuf<T> {
+        let mut deque = RingBuf::new();
         do d.read_seq |d, len| {
             for uint::range(0, len) |i| {
-                deque.add_back(d.read_seq_elt(i, |d| Decodable::decode(d)));
+                deque.push_back(d.read_seq_elt(i, |d| Decodable::decode(d)));
             }
         }
         deque
-- 
cgit 1.4.1-3-g733a5