auto merge of #8604 : kballard/rust/iter-size-hint, r=graydon
Implement `size_hint()` on the new std::vec Iterators. Add or update `size_hint()` on std::iterator Iterators where appropriate. r? @thestinger
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@ -18,7 +18,7 @@
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*/
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use cmp;
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use num::{Zero, One, Integer, Saturating};
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use num::{Zero, One, Integer, CheckedAdd, Saturating};
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use option::{Option, Some, None};
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use ops::{Add, Mul, Sub};
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use cmp::Ord;
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@ -838,7 +838,7 @@ fn size_hint(&self) -> (uint, Option<uint>) {
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let lower = a_lower.saturating_add(b_lower);
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let upper = match (a_upper, b_upper) {
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(Some(x), Some(y)) => Some(x.saturating_add(y)),
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(Some(x), Some(y)) => x.checked_add(&y),
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_ => None
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};
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@ -1115,6 +1115,21 @@ fn next(&mut self) -> Option<A> {
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if self.peeked.is_some() { self.peeked.take() }
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else { self.iter.next() }
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}
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#[inline]
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fn size_hint(&self) -> (uint, Option<uint>) {
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let (lo, hi) = self.iter.size_hint();
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if self.peeked.is_some() {
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let lo = lo.saturating_add(1);
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let hi = match hi {
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Some(x) => x.checked_add(&1),
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None => None
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};
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(lo, hi)
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} else {
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(lo, hi)
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}
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}
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}
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impl<'self, A, T: Iterator<A>> Peekable<A, T> {
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@ -1122,15 +1137,12 @@ impl<'self, A, T: Iterator<A>> Peekable<A, T> {
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/// or None if the iterator is exhausted.
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#[inline]
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pub fn peek(&'self mut self) -> Option<&'self A> {
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if self.peeked.is_none() {
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self.peeked = self.iter.next();
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}
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match self.peeked {
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Some(ref value) => Some(value),
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None => {
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self.peeked = self.iter.next();
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match self.peeked {
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Some(ref value) => Some(value),
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None => None,
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}
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},
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None => None,
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}
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}
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}
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@ -1376,7 +1388,7 @@ fn size_hint(&self) -> (uint, Option<uint>) {
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let (blo, bhi) = self.backiter.map_default((0, Some(0)), |it| it.size_hint());
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let lo = flo.saturating_add(blo);
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match (self.iter.size_hint(), fhi, bhi) {
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((0, Some(0)), Some(a), Some(b)) => (lo, Some(a.saturating_add(b))),
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((0, Some(0)), Some(a), Some(b)) => (lo, a.checked_add(&b)),
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_ => (lo, None)
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}
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}
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@ -1482,6 +1494,12 @@ impl<'self, A, St> Iterator<A> for Unfoldr<'self, A, St> {
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fn next(&mut self) -> Option<A> {
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(self.f)(&mut self.state)
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}
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#[inline]
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fn size_hint(&self) -> (uint, Option<uint>) {
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// no possible known bounds at this point
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(0, None)
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}
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}
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/// An infinite iterator starting at `start` and advancing by `step` with each
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@ -1525,6 +1543,9 @@ fn next(&mut self) -> Option<A> {
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None
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}
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}
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// FIXME: #8606 Implement size_hint() on Range
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// Blocked on #8605 Need numeric trait for converting to `Option<uint>`
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}
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impl<A: Sub<A, A> + Integer + Ord + Clone> DoubleEndedIterator<A> for Range<A> {
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@ -65,7 +65,7 @@
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use cmp;
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use iterator::*;
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use libc::c_void;
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use num::Zero;
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use num::{Integer, Zero, CheckedAdd, Saturating};
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use option::{None, Option, Some};
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use ptr::to_unsafe_ptr;
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use ptr;
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@ -209,6 +209,7 @@ pub struct SplitIterator<'self, T> {
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}
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impl<'self, T> Iterator<&'self [T]> for SplitIterator<'self, T> {
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#[inline]
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fn next(&mut self) -> Option<&'self [T]> {
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if self.finished { return None; }
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@ -230,6 +231,21 @@ fn next(&mut self) -> Option<&'self [T]> {
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}
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}
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}
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#[inline]
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fn size_hint(&self) -> (uint, Option<uint>) {
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if self.finished {
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return (0, Some(0))
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}
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// if the predicate doesn't match anything, we yield one slice
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// if it matches every element, we yield N+1 empty slices where
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// N is either the number of elements or the number of splits.
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match (self.v.len(), self.n) {
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(0,_) => (1, Some(1)),
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(_,0) => (1, Some(1)),
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(l,n) => (1, cmp::min(l,n).checked_add(&1u))
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}
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}
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}
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/// An iterator over the slices of a vector separated by elements that
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@ -242,6 +258,7 @@ pub struct RSplitIterator<'self, T> {
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}
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impl<'self, T> Iterator<&'self [T]> for RSplitIterator<'self, T> {
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#[inline]
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fn next(&mut self) -> Option<&'self [T]> {
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if self.finished { return None; }
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@ -263,6 +280,18 @@ fn next(&mut self) -> Option<&'self [T]> {
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}
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}
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}
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#[inline]
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fn size_hint(&self) -> (uint, Option<uint>) {
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if self.finished {
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return (0, Some(0))
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}
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match (self.v.len(), self.n) {
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(0,_) => (1, Some(1)),
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(_,0) => (1, Some(1)),
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(l,n) => (1, cmp::min(l,n).checked_add(&1u))
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}
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}
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}
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// Appending
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@ -453,6 +482,7 @@ pub struct WindowIter<'self, T> {
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}
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impl<'self, T> Iterator<&'self [T]> for WindowIter<'self, T> {
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#[inline]
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fn next(&mut self) -> Option<&'self [T]> {
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if self.size > self.v.len() {
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None
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@ -462,6 +492,16 @@ fn next(&mut self) -> Option<&'self [T]> {
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ret
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}
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}
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#[inline]
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fn size_hint(&self) -> (uint, Option<uint>) {
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if self.size > self.v.len() {
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(0, Some(0))
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} else {
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let x = self.v.len() - self.size;
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(x.saturating_add(1), x.checked_add(&1u))
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}
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}
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}
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/// An iterator over a vector in (non-overlapping) chunks (`size`
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@ -476,6 +516,7 @@ pub struct ChunkIter<'self, T> {
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}
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impl<'self, T> Iterator<&'self [T]> for ChunkIter<'self, T> {
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#[inline]
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fn next(&mut self) -> Option<&'self [T]> {
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if self.v.len() == 0 {
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None
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@ -487,9 +528,21 @@ fn next(&mut self) -> Option<&'self [T]> {
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Some(fst)
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}
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}
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#[inline]
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fn size_hint(&self) -> (uint, Option<uint>) {
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if self.v.len() == 0 {
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(0, Some(0))
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} else {
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let (n, rem) = self.v.len().div_rem(&self.size);
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let n = if rem > 0 { n+1 } else { n };
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(n, Some(n))
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}
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}
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}
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impl<'self, T> DoubleEndedIterator<&'self [T]> for ChunkIter<'self, T> {
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#[inline]
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fn next_back(&mut self) -> Option<&'self [T]> {
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if self.v.len() == 0 {
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None
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@ -2236,6 +2289,7 @@ fn indexable(&self) -> uint {
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exact
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}
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#[inline]
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fn idx(&self, index: uint) -> Option<&'self T> {
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unsafe {
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if index < self.indexable() {
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@ -2281,6 +2335,7 @@ pub struct MoveIterator<T> {
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}
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impl<T> Iterator<T> for MoveIterator<T> {
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#[inline]
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fn next(&mut self) -> Option<T> {
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// this is peculiar, but is required for safety with respect
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// to dtors. It traverses the first half of the vec, and
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@ -2298,6 +2353,12 @@ fn next(&mut self) -> Option<T> {
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self.v.pop_opt()
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}
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#[inline]
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fn size_hint(&self) -> (uint, Option<uint>) {
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let l = self.v.len();
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(l, Some(l))
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}
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}
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/// An iterator that moves out of a vector in reverse order.
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@ -2307,9 +2368,16 @@ pub struct MoveRevIterator<T> {
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}
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impl<T> Iterator<T> for MoveRevIterator<T> {
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#[inline]
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fn next(&mut self) -> Option<T> {
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self.v.pop_opt()
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}
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#[inline]
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fn size_hint(&self) -> (uint, Option<uint>) {
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let l = self.v.len();
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(l, Some(l))
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}
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}
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impl<A> FromIterator<A> for ~[A] {
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