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//===----------------------------------------------------------------------===//
//
// This source file is part of the Swift Collections open source project
//
// Copyright (c) 2022 - 2024 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
//
//===----------------------------------------------------------------------===//
#if !COLLECTIONS_SINGLE_MODULE
import InternalCollectionsUtilities
#endif
// FIXME: These are non-standard extensions generalizing ==.
extension BitSet {
/// Returns a Boolean value indicating whether two bit sets are equal. Two
/// bit sets are considered equal if they contain the same elements.
///
/// - Complexity: O(*max*), where *max* is value of the largest member of
/// either set.
public func isEqualSet(to other: Self) -> Bool {
self._storage == other._storage
}
/// Returns a Boolean value indicating whether a bit set is equal to a counted
/// bit set, i.e., whether they contain the same values.
///
/// - Complexity: O(*max*), where *max* is value of the largest member of
/// either set.
public func isEqualSet(to other: BitSet.Counted) -> Bool {
self.isEqualSet(to: other._bits)
}
/// Returns a Boolean value indicating whether a bit set is equal to a range
/// of integers, i.e., whether they contain the same values.
///
/// - Complexity: O(min(*max*, `other.upperBound`), where *max* is the largest
/// member of `self`.
public func isEqualSet(to other: Range<Int>) -> Bool {
guard let other = other._toUInt() else { return false }
return _read { $0.isEqualSet(to: other) }
}
/// Returns a Boolean value indicating whether this bit set contains the same
/// elements as the given `other` sequence.
///
/// Duplicate items in `other` do not prevent it from comparing equal to
/// `self`.
///
/// let bits: BitSet = [0, 1, 5, 6]
/// let other = [5, 5, 0, 1, 1, 6, 5, 0, 1, 6, 6, 5]
///
/// bits.isEqualSet(to: other) // true
///
/// - Complexity: O(*n*), where *n* is the number of items in `other`.
public func isEqualSet(to other: some Sequence<Int>) -> Bool {
if let other = _specialize(other, for: BitSet.self) {
return isEqualSet(to: other)
}
if let other = _specialize(other, for: BitSet.Counted.self) {
return isEqualSet(to: other)
}
if let other = _specialize(other, for: Range<Int>.self) {
return isEqualSet(to: other)
}
if self.isEmpty {
return other.allSatisfy { _ in false }
}
if other is _UniqueCollection {
// We don't need to create a temporary set.
guard other.underestimatedCount <= self.count else { return false }
var seen = 0
for item in other {
guard let item = UInt(exactly: item) else { return false }
guard self._contains(item) else { return false}
seen &+= 1
}
precondition(
seen <= self.count,
// Otherwise other.underestimatedCount != other.count
"Invalid Collection '\(type(of: other))' (bad underestimatedCount)")
return seen == self.count
}
var seen: BitSet? = BitSet(reservingCapacity: self.max()!)
var it = other.makeIterator()
while let item = it.next() {
guard let item = UInt(exactly: item) else { return false }
guard self._contains(item) else { return false}
seen!._insert(item) // Ignore dupes
if seen!.count == self.count {
// We've seen them all. Stop further accounting.
seen = nil
break
}
}
guard seen == nil else { return false }
while let item = it.next() {
guard let item = UInt(exactly: item) else { return false }
guard self._contains(item) else { return false}
}
return true
}
}
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