collections::bitv: replace internal iterators with external ones
This commit is contained in:
Andrew Poelstra
parent
da0d4be378
commit
a7f335a09c
@ -15,7 +15,7 @@ use core::prelude::*;
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use core::cmp;
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use core::default::Default;
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use core::fmt;
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use core::iter::{Map, Zip};
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use core::iter::{Map, Take, Zip};
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use core::ops;
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use core::slice;
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use core::uint;
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@ -382,21 +382,6 @@ impl cmp::PartialEq for Bitv {
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impl cmp::Eq for Bitv {}
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#[inline]
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fn iterate_bits(base: uint, bits: uint, f: |uint| -> bool) -> bool {
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if bits == 0 {
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return true;
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}
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for i in range(0u, uint::BITS) {
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if bits & (1 << i) != 0 {
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if !f(base + i) {
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return false;
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}
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}
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}
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return true;
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}
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/// An iterator for `Bitv`.
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pub struct Bits<'a> {
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bitv: &'a Bitv,
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@ -553,39 +538,45 @@ impl BitvSet {
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BitPositions {set: self, next_idx: 0}
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}
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pub fn difference(&self, other: &BitvSet, f: |&uint| -> bool) -> bool {
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for (i, w1, w2) in self.commons(other) {
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if !iterate_bits(i, w1 & !w2, |b| f(&b)) {
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return false
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}
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};
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/* everything we have that they don't also shows up */
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self.outliers(other).advance(|(mine, i, w)|
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!mine || iterate_bits(i, w, |b| f(&b))
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)
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pub fn difference<'a>(&'a self, other: &'a BitvSet) -> TwoBitPositions<'a> {
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TwoBitPositions {
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set: self,
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other: other,
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merge: |w1, w2| w1 & !w2,
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current_word: 0,
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next_idx: 0
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}
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}
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pub fn symmetric_difference(&self, other: &BitvSet, f: |&uint| -> bool)
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-> bool {
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for (i, w1, w2) in self.commons(other) {
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if !iterate_bits(i, w1 ^ w2, |b| f(&b)) {
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return false
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}
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};
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self.outliers(other).advance(|(_, i, w)| iterate_bits(i, w, |b| f(&b)))
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pub fn symmetric_difference<'a>(&'a self, other: &'a BitvSet) -> TwoBitPositions<'a> {
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TwoBitPositions {
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set: self,
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other: other,
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merge: |w1, w2| w1 ^ w2,
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current_word: 0,
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next_idx: 0
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}
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}
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pub fn intersection(&self, other: &BitvSet, f: |&uint| -> bool) -> bool {
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self.commons(other).advance(|(i, w1, w2)| iterate_bits(i, w1 & w2, |b| f(&b)))
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pub fn intersection<'a>(&'a self, other: &'a BitvSet) -> Take<TwoBitPositions<'a>> {
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let min = cmp::min(self.capacity(), other.capacity());
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TwoBitPositions {
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set: self,
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other: other,
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merge: |w1, w2| w1 & w2,
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current_word: 0,
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next_idx: 0
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}.take(min)
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}
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pub fn union(&self, other: &BitvSet, f: |&uint| -> bool) -> bool {
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for (i, w1, w2) in self.commons(other) {
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if !iterate_bits(i, w1 | w2, |b| f(&b)) {
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return false
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}
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};
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self.outliers(other).advance(|(_, i, w)| iterate_bits(i, w, |b| f(&b)))
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pub fn union<'a>(&'a self, other: &'a BitvSet) -> TwoBitPositions<'a> {
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TwoBitPositions {
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set: self,
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other: other,
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merge: |w1, w2| w1 | w2,
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current_word: 0,
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next_idx: 0
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}
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}
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}
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@ -634,7 +625,7 @@ impl Set<uint> for BitvSet {
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}
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fn is_disjoint(&self, other: &BitvSet) -> bool {
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self.intersection(other, |_| false)
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self.intersection(other).count() > 0
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}
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fn is_subset(&self, other: &BitvSet) -> bool {
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@ -737,6 +728,14 @@ pub struct BitPositions<'a> {
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next_idx: uint
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}
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pub struct TwoBitPositions<'a> {
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set: &'a BitvSet,
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other: &'a BitvSet,
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merge: |uint, uint|: 'a -> uint,
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current_word: uint,
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next_idx: uint
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}
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impl<'a> Iterator<uint> for BitPositions<'a> {
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#[inline]
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fn next(&mut self) -> Option<uint> {
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@ -757,6 +756,41 @@ impl<'a> Iterator<uint> for BitPositions<'a> {
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}
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}
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impl<'a> Iterator<uint> for TwoBitPositions<'a> {
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#[inline]
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fn next(&mut self) -> Option<uint> {
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while self.next_idx < self.set.capacity() ||
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self.next_idx < self.other.capacity() {
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let bit_idx = self.next_idx % uint::BITS;
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if bit_idx == 0 {
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let &BitvSet(ref s_bitv) = self.set;
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let &BitvSet(ref o_bitv) = self.other;
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// Merging the two words is a bit of an awkward dance since
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// one Bitv might be longer than the other
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let word_idx = self.next_idx / uint::BITS;
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let w1 = if word_idx < s_bitv.storage.len() {
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*s_bitv.storage.get(word_idx)
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} else { 0 };
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let w2 = if word_idx < o_bitv.storage.len() {
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*o_bitv.storage.get(word_idx)
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} else { 0 };
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self.current_word = (self.merge)(w1, w2);
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}
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self.next_idx += 1;
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if self.current_word & (1 << bit_idx) != 0 {
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return Some(self.next_idx - 1);
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}
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}
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return None;
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}
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fn size_hint(&self) -> (uint, Option<uint>) {
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let cap = cmp::max(self.set.capacity(), self.other.capacity());
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(0, Some(cap - self.next_idx))
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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 std::prelude::*;
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@ -1274,8 +1308,8 @@ mod tests {
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let mut i = 0;
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let expected = [3, 5, 11, 77];
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a.intersection(&b, |x| {
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assert_eq!(*x, expected[i]);
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a.intersection(&b).advance(|x| {
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assert_eq!(x, expected[i]);
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i += 1;
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true
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});
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@ -1298,8 +1332,8 @@ mod tests {
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let mut i = 0;
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let expected = [1, 5, 500];
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a.difference(&b, |x| {
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assert_eq!(*x, expected[i]);
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a.difference(&b).advance(|x| {
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assert_eq!(x, expected[i]);
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i += 1;
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true
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});
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@ -1324,8 +1358,8 @@ mod tests {
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let mut i = 0;
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let expected = [1, 5, 11, 14, 220];
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a.symmetric_difference(&b, |x| {
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assert_eq!(*x, expected[i]);
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a.symmetric_difference(&b).advance(|x| {
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assert_eq!(x, expected[i]);
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i += 1;
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true
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});
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@ -1353,8 +1387,8 @@ mod tests {
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let mut i = 0;
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let expected = [1, 3, 5, 9, 11, 13, 19, 24, 160];
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a.union(&b, |x| {
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assert_eq!(*x, expected[i]);
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a.union(&b).advance(|x| {
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assert_eq!(x, expected[i]);
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i += 1;
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true
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});
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