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).

1 files changed, 705 insertions, 0 deletions

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());
+    }
+}