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158 lines
3.5 KiB
158 lines
3.5 KiB
use super::*;
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/// An iterator that may be empty.
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#[derive(Debug, Clone)]
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pub struct MaybeIter<I, T>(Option<I>)
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where I: Iterator<Item=T>;
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pub trait OptionIterExt<I, T>: Sized
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where I: Iterator<Item=T>
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{
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/// Map this `Option<Iterator>` into an iterator that will yield the items of the iterator if it is present.
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fn map_into_iter(self) -> MaybeIter<I, T>;
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}
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impl<E, T, I, Into: IntoIterator<IntoIter=I, Item=T>> OptionIterExt<I, T> for Result<Into, E>
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where I: Iterator<Item = T>
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{
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#[inline] fn map_into_iter(self) -> MaybeIter<I, T> {
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MaybeIter(self.ok().map(|x| x.into_iter()))
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}
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}
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impl<T, I, Into: IntoIterator<IntoIter=I, Item=T>> OptionIterExt<I, T> for Option<Into>
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where I: Iterator<Item = T>
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{
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#[inline] fn map_into_iter(self) -> MaybeIter<I, T> {
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MaybeIter(self.map(|x| x.into_iter()))
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}
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}
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impl<I, T> Iterator for MaybeIter<I, T>
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where I: Iterator<Item=T>
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{
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type Item = T;
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fn next(&mut self) -> Option<Self::Item>
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{
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if let Some(ref mut iter) = self.0
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{
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iter.next()
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} else {
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None
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}
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}
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fn size_hint(&self) -> (usize, Option<usize>) {
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match &self.0 {
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Some(i) => i.size_hint(),
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None => (0, Some(0)),
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}
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}
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}
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impl<I, T> FusedIterator for MaybeIter<I, T>
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where I: Iterator<Item=T> + FusedIterator{}
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impl<I, T> ExactSizeIterator for MaybeIter<I, T>
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where I: Iterator<Item=T> + ExactSizeIterator{}
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impl<I, T> DoubleEndedIterator for MaybeIter<I, T>
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where I: Iterator<Item=T> + DoubleEndedIterator
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{
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fn next_back(&mut self) -> Option<Self::Item> {
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if let Some(ref mut iter) = self.0
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{
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iter.next_back()
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} else {
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None
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}
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}
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}
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/// An iterator that deduplicates an iterator over references by pointer identity.
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#[derive(Debug, Clone)]
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pub struct DedupedRefIter<'a, I, T: ?Sized + 'a>(I, BTreeSet<*const T>)
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where I: Iterator<Item = &'a T>;
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pub trait DedupIterExt<'a, I, T: ?Sized + 'a>
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where I: Iterator<Item = &'a T>
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{
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/// Deduplicate this iterator by pointer identity.
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fn dedup_ref(self) -> DedupedRefIter<'a, I, T>;
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}
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impl<'a, I, T:?Sized+'a, IntoIter> DedupIterExt<'a, I, T> for IntoIter
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where IntoIter: IntoIterator<IntoIter=I>,
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I: Iterator<Item= &'a T>
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{
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fn dedup_ref(self) -> DedupedRefIter<'a, I, T> {
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DedupedRefIter(self.into_iter(), BTreeSet::new())
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}
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}
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impl<'a, I, T:?Sized + 'a> Iterator for DedupedRefIter<'a, I, T>
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where I: Iterator<Item = &'a T>
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{
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type Item = &'a T;
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fn next(&mut self) -> Option<Self::Item>
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{
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Some(loop {
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if let Some(next) = self.0.next()
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{
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if self.1.insert(next as *const T) {
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break next;
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}
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} else {
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return None;
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}
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})
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}
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fn size_hint(&self) -> (usize, Option<usize>) {
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match self.0.size_hint()
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{
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(0, h) => (0, h),
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(_, h) => (1, h),
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}
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}
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}
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impl<'a, I, T:?Sized + 'a> DoubleEndedIterator for DedupedRefIter<'a, I, T>
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where I: Iterator<Item = &'a T> + DoubleEndedIterator
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{
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fn next_back(&mut self) -> Option<Self::Item> {
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Some(loop {
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if let Some(next) = self.0.next_back()
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{
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if self.1.insert(next as *const T) {
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break next;
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}
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} else {
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return None;
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}
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})
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}
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}
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impl<'a, I, T:?Sized + 'a> FusedIterator for DedupedRefIter<'a, I, T>
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where I: Iterator<Item = &'a T> + FusedIterator{}
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pub trait ContainsAllExt<T>
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{
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fn contains_all<V: AsRef<[T]>>(&self, items: V) -> bool;
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}
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impl<T, S> ContainsAllExt<T> for S
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where S: AsRef<[T]>,
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T: PartialEq,
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{
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fn contains_all<V: AsRef<[T]>>(&self, items: V) -> bool {
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let s = self.as_ref();
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for x in items.as_ref().iter()
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{
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if !s.contains(x) {
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return false;
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}
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}
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true
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}
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}
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