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//===----------------------------------------------------------------------===//
//
// This source file is part of the Swift Collections open source project
//
// Copyright (c) 2023 - 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 swift(>=5.8)
@available(macOS 13.3, iOS 16.4, watchOS 9.4, tvOS 16.4, *)
extension BigString: Hashable {
public func hash(into hasher: inout Hasher) {
hashCharacters(into: &hasher)
}
}
@available(macOS 13.3, iOS 16.4, watchOS 9.4, tvOS 16.4, *)
extension BigString {
internal func hashCharacters(into hasher: inout Hasher) {
// FIXME: Implement properly normalized comparisons & hashing.
// This is somewhat tricky as we shouldn't just normalize individual pieces of the string
// split up on random Character boundaries -- Unicode does not promise that
// norm(a + c) == norm(a) + norm(b) in this case.
// To do this properly, we'll probably need to expose new stdlib entry points. :-/
var it = self.makeIterator()
while let character = it.next() {
let s = String(character)
s._withNFCCodeUnits { hasher.combine($0) }
}
hasher.combine(0xFF as UInt8)
}
/// Feed the UTF-8 encoding of `self` into hasher, with a terminating byte.
internal func hashUTF8(into hasher: inout Hasher) {
for chunk in self._rope {
var string = chunk.string
string.withUTF8 {
hasher.combine(bytes: .init($0))
}
}
hasher.combine(0xFF as UInt8)
}
/// Feed the UTF-8 encoding of `self[start..<end]` into hasher, with a terminating byte.
internal func hashUTF8(into hasher: inout Hasher, from start: Index, to end: Index) {
assert(start <= end)
_foreachChunk(from: start, to: end) { str in
var str = str
str.withUTF8 {
let buffer = UnsafeRawBufferPointer($0)
hasher.combine(bytes: buffer)
}
}
hasher.combine(0xFF as UInt8)
}
}
#endif
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