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//===----------------------------------------------------------------------===//
//
// This source file is part of the Swift Collections open source project
//
// Copyright (c) 2021 - 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
extension BitArray {
internal mutating func _copy(
from range: Range<Int>,
to target: Int
) {
_update { handle in
handle.copy(from: range, to: target)
}
}
internal mutating func _copy(
from range: Range<Int>,
in source: UnsafeBufferPointer<_Word>,
to target: Int
) {
_update { handle in
handle.copy(from: range, in: source, to: target)
}
}
internal mutating func _copy(
from source: BitArray,
to target: Int
) {
_copy(from: source[...], to: target)
}
internal mutating func _copy(
from source: BitArray.SubSequence,
to target: Int
) {
let range = source._bounds
source.base._storage.withUnsafeBufferPointer { words in
self._copy(from: range, in: words, to: target)
}
}
internal mutating func _copy<S: Sequence>(
from source: S,
to range: Range<Int>
) where S.Element == Bool {
_update { $0.copy(from: source, to: range) }
}
}
extension BitArray._UnsafeHandle {
internal mutating func _copy(
bits: _Word, count: UInt, to target: _BitPosition
) {
assert(count <= _Word.capacity)
assert(count == _Word.capacity || bits.shiftedDown(by: count).isEmpty)
assert(target.value + count <= _count)
let start = target.split
let end = _BitPosition(target.value + count).endSplit
let words = _mutableWords
if start.word == end.word {
let mask = _Word(from: start.bit, to: end.bit)
words[start.word].formIntersection(mask.complement())
words[start.word].formUnion(bits.shiftedUp(by: start.bit))
return
}
assert(start.word + 1 == end.word)
words[start.word].formIntersection(_Word(upTo: start.bit))
words[start.word].formUnion(bits.shiftedUp(by: start.bit))
words[end.word].formIntersection(_Word(upTo: end.bit).complement())
words[end.word].formUnion(
bits.shiftedDown(by: UInt(_Word.capacity) &- start.bit))
}
internal mutating func copy(
from range: Range<Int>,
to target: Int
) {
assert(
range.lowerBound >= 0 && range.upperBound <= self.count,
"Source range out of bounds")
copy(from: range, in: _words, to: target)
}
internal mutating func copy(
from range: Range<Int>,
in source: UnsafeBufferPointer<_Word>,
to target: Int
) {
ensureMutable()
assert(
range.lowerBound >= 0 && range.upperBound <= source.count * _Word.capacity,
"Source range out of bounds")
assert(
target >= 0 && target + range.count <= count,
"Target out of bounds")
guard !range.isEmpty else { return }
func goForward() -> Bool {
let target = _BitPosition(target).split
let lowerSource = _BitPosition(range.lowerBound).split
let upperSource = _BitPosition(range.upperBound).endSplit
let targetPtr = _words._ptr(at: target.word)
let lowerSourcePtr = source._ptr(at: lowerSource.word)
let upperSourcePtr = source._ptr(at: upperSource.word)
if targetPtr < lowerSourcePtr || targetPtr > upperSourcePtr {
return true
}
if targetPtr == lowerSourcePtr, target.bit < lowerSource.bit {
return true
}
if targetPtr == upperSourcePtr, target.bit >= upperSource.bit {
return true
}
return false
}
if goForward() {
// Copy forward from a disjoint or following overlapping range.
var src = _ChunkedBitsForwardIterator(words: source, range: range)
var dst = _BitPosition(target)
while let (bits, count) = src.next() {
_copy(bits: bits, count: count, to: dst)
dst.value += count
}
assert(dst.value == target + range.count)
} else {
// Copy backward from a non-following overlapping range.
var src = _ChunkedBitsBackwardIterator(words: source, range: range)
var dst = _BitPosition(target + range.count)
while let (bits, count) = src.next() {
dst.value -= count
_copy(bits: bits, count: count, to: dst)
}
assert(dst.value == target)
}
}
}
extension BitArray._UnsafeHandle {
internal mutating func copy(
from source: some Sequence<Bool>,
to range: Range<Int>
) {
assert(range.lowerBound >= 0 && range.upperBound <= self.count)
var pos = _BitPosition(range.lowerBound)
var it = source.makeIterator()
if pos.bit > 0 {
let (bits, count) = it._nextChunk(
maximumCount: UInt(_Word.capacity) - pos.bit)
_copy(bits: bits, count: count, to: pos)
pos.value += count
}
while true {
let (bits, count) = it._nextChunk()
guard count > 0 else { break }
assert(pos.bit == 0)
_copy(bits: bits, count: count, to: pos)
pos.value += count
}
precondition(pos.value == range.upperBound)
}
}
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