auto merge of #7562 : blake2-ppc/rust/deque, r=cmr
Fix an assertion in grow when using add_front. Speeds up grow (and the functions that use it) by a lot. We retain the vector instead of creating it anew for each grow. The struct field hi is removed since it is redundant, and all iterators are updated to use a representation closer to the Deque itself, it should make it work even if deque sizes are not powers of two. Deque::with_capacity is also implemented, but .reserve() is not yet done.
This commit is contained in:
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commit
c1c7768b32
@ -11,17 +11,17 @@
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//! A double-ended queue implemented as a circular buffer
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use std::uint;
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use std::util::replace;
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use std::vec;
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use std::cast::transmute;
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use std::iterator::FromIterator;
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static INITIAL_CAPACITY: uint = 32u; // 2^5
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static INITIAL_CAPACITY: uint = 8u; // 2^3
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static MINIMUM_CAPACITY: uint = 2u;
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#[allow(missing_doc)]
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#[deriving(Clone)]
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pub struct Deque<T> {
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priv nelts: uint,
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priv lo: uint,
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priv hi: uint,
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priv elts: ~[Option<T>]
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}
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@ -39,26 +39,36 @@ impl<T> Mutable for Deque<T> {
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for self.elts.mut_iter().advance |x| { *x = None }
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self.nelts = 0;
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self.lo = 0;
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self.hi = 0;
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}
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}
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impl<T> Deque<T> {
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/// Create an empty Deque
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pub fn new() -> Deque<T> {
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Deque{nelts: 0, lo: 0, hi: 0,
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elts: vec::from_fn(INITIAL_CAPACITY, |_| None)}
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Deque::with_capacity(INITIAL_CAPACITY)
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}
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/// Create an empty Deque with space for at least `n` elements.
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pub fn with_capacity(n: uint) -> Deque<T> {
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Deque{nelts: 0, lo: 0,
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elts: vec::from_fn(uint::max(MINIMUM_CAPACITY, n), |_| None)}
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}
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/// Return a reference to the first element in the deque
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///
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/// Fails if the deque is empty
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pub fn peek_front<'a>(&'a self) -> &'a T { get(self.elts, self.lo) }
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pub fn peek_front<'a>(&'a self) -> &'a T { get(self.elts, self.raw_index(0)) }
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/// Return a reference to the last element in the deque
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///
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/// Fails if the deque is empty
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pub fn peek_back<'a>(&'a self) -> &'a T { get(self.elts, self.hi - 1u) }
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pub fn peek_back<'a>(&'a self) -> &'a T {
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if self.nelts > 0 {
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get(self.elts, self.raw_index(self.nelts - 1))
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} else {
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fail!("peek_back: empty deque");
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}
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}
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/// Retrieve an element in the deque by index
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///
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@ -68,16 +78,6 @@ impl<T> Deque<T> {
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get(self.elts, idx)
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}
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/// Iterate over the elements in the deque
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pub fn each(&self, f: &fn(&T) -> bool) -> bool {
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self.eachi(|_i, e| f(e))
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}
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/// Iterate over the elements in the deque by index
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pub fn eachi(&self, f: &fn(uint, &T) -> bool) -> bool {
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uint::range(0, self.nelts, |i| f(i, self.get(i as int)))
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}
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/// Remove and return the first element in the deque
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///
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/// Fails if the deque is empty
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@ -88,43 +88,39 @@ impl<T> Deque<T> {
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result
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}
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/// Return index in underlying vec for a given logical element index
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fn raw_index(&self, idx: uint) -> uint {
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raw_index(self.lo, self.elts.len(), idx)
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}
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/// Remove and return the last element in the deque
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///
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/// Fails if the deque is empty
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pub fn pop_back(&mut self) -> T {
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if self.hi == 0u {
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self.hi = self.elts.len() - 1u;
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} else { self.hi -= 1u; }
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let result = self.elts[self.hi].swap_unwrap();
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self.elts[self.hi] = None;
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self.nelts -= 1u;
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result
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self.nelts -= 1;
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let hi = self.raw_index(self.nelts);
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self.elts[hi].swap_unwrap()
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}
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/// Prepend an element to the deque
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pub fn add_front(&mut self, t: T) {
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let oldlo = self.lo;
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if self.nelts == self.elts.len() {
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grow(self.nelts, &mut self.lo, &mut self.elts);
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}
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if self.lo == 0u {
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self.lo = self.elts.len() - 1u;
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} else { self.lo -= 1u; }
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if self.lo == self.hi {
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self.elts = grow(self.nelts, oldlo, self.elts);
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self.lo = self.elts.len() - 1u;
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self.hi = self.nelts;
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}
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self.elts[self.lo] = Some(t);
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self.nelts += 1u;
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}
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/// Append an element to the deque
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pub fn add_back(&mut self, t: T) {
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if self.lo == self.hi && self.nelts != 0u {
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self.elts = grow(self.nelts, self.lo, self.elts);
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self.lo = 0u;
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self.hi = self.nelts;
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if self.nelts == self.elts.len() {
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grow(self.nelts, &mut self.lo, &mut self.elts);
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}
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self.elts[self.hi] = Some(t);
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self.hi = (self.hi + 1u) % self.elts.len();
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let hi = self.raw_index(self.nelts);
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self.elts[hi] = Some(t);
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self.nelts += 1u;
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}
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@ -155,42 +151,39 @@ impl<T> Deque<T> {
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/// Front-to-back iterator.
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pub fn iter<'a>(&'a self) -> DequeIterator<'a, T> {
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DequeIterator { idx: self.lo, nelts: self.nelts, used: 0, vec: self.elts }
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DequeIterator{index: 0, nelts: self.nelts, elts: self.elts, lo: self.lo}
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}
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/// Front-to-back iterator which returns mutable values.
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pub fn mut_iter<'a>(&'a mut self) -> DequeMutIterator<'a, T> {
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DequeMutIterator { idx: self.lo, nelts: self.nelts, used: 0, vec: self.elts }
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DequeMutIterator{index: 0, nelts: self.nelts, elts: self.elts, lo: self.lo}
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}
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/// Back-to-front iterator.
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pub fn rev_iter<'a>(&'a self) -> DequeRevIterator<'a, T> {
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DequeRevIterator { idx: self.hi - 1u, nelts: self.nelts, used: 0, vec: self.elts }
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DequeRevIterator{index: self.nelts-1, nelts: self.nelts, elts: self.elts,
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lo: self.lo}
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}
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/// Back-to-front iterator which returns mutable values.
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pub fn mut_rev_iter<'a>(&'a mut self) -> DequeMutRevIterator<'a, T> {
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DequeMutRevIterator { idx: self.hi - 1u, nelts: self.nelts, used: 0, vec: self.elts }
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DequeMutRevIterator{index: self.nelts-1, nelts: self.nelts, elts: self.elts,
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lo: self.lo}
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}
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}
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macro_rules! iterator {
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(impl $name:ident -> $elem:ty, $step:expr) => {
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(impl $name:ident -> $elem:ty, $getter:ident, $step:expr) => {
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impl<'self, T> Iterator<$elem> for $name<'self, T> {
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#[inline]
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fn next(&mut self) -> Option<$elem> {
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if self.used >= self.nelts {
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if self.nelts == 0 {
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return None;
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}
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let ret = unsafe {
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match self.vec[self.idx % self.vec.len()] {
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Some(ref e) => Some(transmute(e)),
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None => None
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}
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};
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self.idx += $step;
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self.used += 1;
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ret
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let raw_index = raw_index(self.lo, self.elts.len(), self.index);
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self.index += $step;
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self.nelts -= 1;
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Some(self.elts[raw_index]. $getter ())
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}
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}
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}
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@ -198,64 +191,115 @@ macro_rules! iterator {
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/// Deque iterator
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pub struct DequeIterator<'self, T> {
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priv idx: uint,
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priv lo: uint,
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priv nelts: uint,
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priv used: uint,
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priv vec: &'self [Option<T>]
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priv index: uint,
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priv elts: &'self [Option<T>],
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}
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iterator!{impl DequeIterator -> &'self T, 1}
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iterator!{impl DequeIterator -> &'self T, get_ref, 1}
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/// Deque reverse iterator
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pub struct DequeRevIterator<'self, T> {
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priv idx: uint,
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priv lo: uint,
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priv nelts: uint,
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priv used: uint,
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priv vec: &'self [Option<T>]
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priv index: uint,
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priv elts: &'self [Option<T>],
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}
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iterator!{impl DequeRevIterator -> &'self T, -1}
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iterator!{impl DequeRevIterator -> &'self T, get_ref, -1}
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/// Deque mutable iterator
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pub struct DequeMutIterator<'self, T> {
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priv idx: uint,
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priv lo: uint,
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priv nelts: uint,
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priv used: uint,
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priv vec: &'self mut [Option<T>]
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priv index: uint,
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priv elts: &'self mut [Option<T>],
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}
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iterator!{impl DequeMutIterator -> &'self mut T, 1}
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iterator!{impl DequeMutIterator -> &'self mut T, get_mut_ref, 1}
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/// Deque mutable reverse iterator
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pub struct DequeMutRevIterator<'self, T> {
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priv idx: uint,
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priv lo: uint,
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priv nelts: uint,
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priv used: uint,
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priv vec: &'self mut [Option<T>]
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priv index: uint,
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priv elts: &'self mut [Option<T>],
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}
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iterator!{impl DequeMutRevIterator -> &'self mut T, -1}
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iterator!{impl DequeMutRevIterator -> &'self mut T, get_mut_ref, -1}
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/// Grow is only called on full elts, so nelts is also len(elts), unlike
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/// elsewhere.
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fn grow<T>(nelts: uint, lo: uint, elts: &mut [Option<T>]) -> ~[Option<T>] {
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fn grow<T>(nelts: uint, loptr: &mut uint, elts: &mut ~[Option<T>]) {
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assert_eq!(nelts, elts.len());
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let mut rv = ~[];
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let lo = *loptr;
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let newlen = nelts * 2;
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elts.reserve(newlen);
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do rv.grow_fn(nelts + 1) |i| {
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replace(&mut elts[(lo + i) % nelts], None)
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/* fill with None */
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for uint::range(elts.len(), elts.capacity()) |_| {
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elts.push(None);
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}
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rv
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/*
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Move the shortest half into the newly reserved area.
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lo ---->|
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nelts ----------->|
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[o o o|o o o o o]
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A [. . .|o o o o o o o o|. . . . .]
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B [o o o|. . . . . . . .|o o o o o]
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*/
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assert!(newlen - nelts/2 >= nelts);
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if lo <= (nelts - lo) { // A
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for uint::range(0, lo) |i| {
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elts.swap(i, nelts + i);
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}
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} else { // B
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for uint::range(lo, nelts) |i| {
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elts.swap(i, newlen - nelts + i);
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}
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*loptr += newlen - nelts;
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}
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}
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fn get<'r, T>(elts: &'r [Option<T>], i: uint) -> &'r T {
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match elts[i] { Some(ref t) => t, _ => fail!() }
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}
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/// Return index in underlying vec for a given logical element index
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fn raw_index(lo: uint, len: uint, index: uint) -> uint {
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if lo >= len - index {
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lo + index - len
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} else {
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lo + index
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}
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}
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impl<A: Eq> Eq for Deque<A> {
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fn eq(&self, other: &Deque<A>) -> bool {
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self.nelts == other.nelts &&
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self.iter().zip(other.iter()).all(|(a, b)| a.eq(b))
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}
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fn ne(&self, other: &Deque<A>) -> bool {
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!self.eq(other)
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}
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}
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impl<A, T: Iterator<A>> FromIterator<A, T> for Deque<A> {
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fn from_iterator(iterator: &mut T) -> Deque<A> {
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let mut deq = Deque::new();
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for iterator.advance |elt| {
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deq.add_back(elt);
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}
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deq
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}
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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use std::cmp::Eq;
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use std::kinds::Copy;
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use std::int;
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use std::{int, uint};
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use extra::test;
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#[test]
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fn test_simple() {
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@ -369,6 +413,61 @@ mod tests {
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assert_eq!(copy *deq.get(3), copy d);
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}
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#[test]
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fn test_add_front_grow() {
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let mut deq = Deque::new();
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for int::range(0, 66) |i| {
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deq.add_front(i);
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}
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assert_eq!(deq.len(), 66);
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for int::range(0, 66) |i| {
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assert_eq!(*deq.get(i), 65 - i);
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}
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let mut deq = Deque::new();
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for int::range(0, 66) |i| {
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deq.add_back(i);
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}
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for int::range(0, 66) |i| {
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assert_eq!(*deq.get(i), i);
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}
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}
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#[bench]
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fn bench_new(b: &mut test::BenchHarness) {
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do b.iter {
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let _ = Deque::new::<u64>();
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}
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}
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#[bench]
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fn bench_add_back(b: &mut test::BenchHarness) {
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let mut deq = Deque::new();
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do b.iter {
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deq.add_back(0);
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}
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}
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#[bench]
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fn bench_add_front(b: &mut test::BenchHarness) {
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let mut deq = Deque::new();
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do b.iter {
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deq.add_front(0);
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}
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}
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#[bench]
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fn bench_grow(b: &mut test::BenchHarness) {
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let mut deq = Deque::new();
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do b.iter {
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for 65.times {
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deq.add_front(1);
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}
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}
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}
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#[deriving(Eq)]
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enum Taggy { One(int), Two(int, int), Three(int, int, int), }
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@ -417,22 +516,13 @@ mod tests {
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}
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#[test]
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fn test_eachi() {
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let mut deq = Deque::new();
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deq.add_back(1);
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deq.add_back(2);
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deq.add_back(3);
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for deq.eachi |i, e| {
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assert_eq!(*e, i + 1);
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}
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deq.pop_front();
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for deq.eachi |i, e| {
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assert_eq!(*e, i + 2);
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}
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fn test_with_capacity() {
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let mut d = Deque::with_capacity(0);
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d.add_back(1);
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assert_eq!(d.len(), 1);
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let mut d = Deque::with_capacity(50);
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d.add_back(1);
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assert_eq!(d.len(), 1);
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}
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#[test]
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@ -462,6 +552,8 @@ mod tests {
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#[test]
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fn test_iter() {
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let mut d = Deque::new();
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assert_eq!(d.iter().next(), None);
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for int::range(0,5) |i| {
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d.add_back(i);
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}
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@ -476,6 +568,8 @@ mod tests {
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#[test]
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fn test_rev_iter() {
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let mut d = Deque::new();
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assert_eq!(d.rev_iter().next(), None);
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for int::range(0,5) |i| {
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d.add_back(i);
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}
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@ -486,4 +580,104 @@ mod tests {
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}
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assert_eq!(d.rev_iter().collect::<~[&int]>(), ~[&4,&3,&2,&1,&0,&6,&7,&8]);
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}
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#[test]
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fn test_mut_iter() {
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let mut d = Deque::new();
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assert!(d.mut_iter().next().is_none());
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for uint::range(0,3) |i| {
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d.add_front(i);
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}
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for d.mut_iter().enumerate().advance |(i, elt)| {
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assert_eq!(*elt, 2 - i);
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*elt = i;
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||||
}
|
||||
|
||||
{
|
||||
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());
|
||||
}
|
||||
}
|
||||
|
||||
@ -682,7 +682,7 @@ impl<
|
||||
> Encodable<S> for Deque<T> {
|
||||
fn encode(&self, s: &mut S) {
|
||||
do s.emit_seq(self.len()) |s| {
|
||||
for self.eachi |i, e| {
|
||||
for self.iter().enumerate().advance |(i, e)| {
|
||||
s.emit_seq_elt(i, |s| e.encode(s));
|
||||
}
|
||||
}
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user