Gave it another go in new environment (Monterey, Xcode 14) got different results:
CFString ascii len:9 CF:N NS(CF):N S(CF):N S(NS):N
CFString ascii len:10 CF:Y NS(CF):Y S(CF):N S(NS):N
CFString utf8 len:9 CF:N NS(CF):N S(CF):N S(NS):N
CFString utf8 len:10 CF:Y NS(CF):Y S(CF):N S(NS):N
CFString utf16LE len:1 CF:Y NS(CF):Y S(CF):N S(NS):N
CFString utf16BE len:1 CF:N NS(CF):N S(CF):N S(NS):N
CFString_chars len:1 CF:Y NS(CF):Y S(CF):N S(NS):N
NSString utf8 len:9 NS:N S(NS):N
NSString utf8 len:10 NS:Y S(NS):N
NSString utf16LE len:1 NS:Y S(NS):N
NSString utf16BE len:20 NS:N S(NS):N
NSString_chars len:1 NS:Y S(NS):N
String utf8 len:20 S:N
String utf16LE len:20 S:N
String_chars len:20 S:N
CFData len:14 CF:Y NS(CF):Y S(CF):N S(NS):N
CFData len:15 CF:Y NS(CF):Y S(CF):Y* S(NS):Y*
NSData len:1 NS:Y S(NS):N
NSData len:20 NS:Y S(NS):N
Data len:14 S:N
Data len:15 S:Y*
i.e. no longer we can have a bridged String that can be mutated via some spooky action at a distance – which is a good thing, e.g. we won't be able breaking Set type invariants, etc. We can still do it with Data though.
Updated source code (kCFAllocatorNull vs nil error fixed).
import Foundation
func test_CFString_bytes<T>(_ testName: String, count: Int, value1: T, value2: T, encoding: CFStringBuiltInEncodings, printDetails: Bool = false) {
let size = count * MemoryLayout<T>.size
let bytes = malloc(size)!
let chars = bytes.assumingMemoryBound(to: T.self)
for i in 0 ..< count {
chars[i] = value1
}
let p = bytes.assumingMemoryBound(to: UInt8.self)
let cf = CFStringCreateWithBytesNoCopy(nil, p, size, encoding.rawValue, false, kCFAllocatorNull)!
let ns = cf as NSString
let sc = cf as String
let sn = ns as String
let cf1 = "\(cf)"
let ns1 = "\(ns)"
let sc1 = "\(sc)"
let sn1 = "\(sn)"
chars.pointee = value2
let cf2 = "\(cf)"
let ns2 = "\(ns)"
let sc2 = "\(sc)"
let sn2 = "\(sn)"
if printDetails {
print("cf1: \(cf1)")
print("ns1: \(ns1)")
print("sc1: \(sc1)")
print("sn1: \(sn1)")
print("-- modification --")
print("cf2: \(cf2)")
print("ns2: \(ns2)")
print("sc2: \(sc2)")
print("sn2: \(sn2)")
}
print("\(testName)\tlen:\(count)\tCF:\(neq(cf1,cf2))\tNS(CF):\(neq(ns1,ns2))\tS(CF):\(neq(sc1,sc2,true))\tS(NS):\(neq(sn1,sn2,true))")
}
func test_CFString_chars(_ testName: String, count: Int, value1: UniChar, value2: UniChar, printDetails: Bool = false) {
let size = count * MemoryLayout<UniChar>.size
let bytes = malloc(size)!
let chars = bytes.assumingMemoryBound(to: UniChar.self)
for i in 0 ..< count {
chars[i] = value1
}
let cf = CFStringCreateWithCharactersNoCopy(nil, chars, count, kCFAllocatorNull)!
let ns = cf as NSString
let sc = cf as String
let sn = ns as String
let cf1 = "\(cf)"
let ns1 = "\(ns)"
let sc1 = "\(sc)"
let sn1 = "\(sn)"
chars.pointee = value2
let cf2 = "\(cf)"
let ns2 = "\(ns)"
let sc2 = "\(sc)"
let sn2 = "\(sn)"
if printDetails {
print("cf1: \(cf1)")
print("ns1: \(ns1)")
print("sc1: \(sc1)")
print("sn1: \(sn1)")
print("-- modification --")
print("cf2: \(cf2)")
print("ns2: \(ns2)")
print("sc2: \(sc2)")
print("sn2: \(sn2)")
}
print("\(testName)\tlen:\(count)\tCF:\(neq(cf1,cf2))\tNS(CF):\(neq(ns1,ns2))\tS(CF):\(neq(sc1,sc2,true))\tS(NS):\(neq(sn1,sn2,true))")
}
func test_NSString_bytes<T>(_ testName: String, count: Int, value1: T, value2: T, encoding: String.Encoding, printDetails: Bool = false) {
let size = count * MemoryLayout<T>.size
let bytes = malloc(size)!
let chars = bytes.assumingMemoryBound(to: T.self)
for i in 0 ..< count {
chars[i] = value1
}
let ns = NSString(bytesNoCopy: bytes, length: size, encoding: encoding.rawValue, freeWhenDone: false)!
let sn = ns as String
let ns1 = "\(ns)"
let sn1 = "\(sn)"
chars.pointee = value2
let ns2 = "\(ns)"
let sn2 = "\(sn)"
if printDetails {
print("ns1: \(ns1)")
print("sn1: \(sn1)")
print("-- modification --")
print("ns2: \(ns2)")
print("sn2: \(sn2)")
}
print("\(testName)\tlen:\(count)\t \tNS:\(neq(ns1,ns2)) \tS(NS):\(neq(sn1,sn2,true))")
}
func test_NSString_chars(_ testName: String, count: Int, value1: UniChar, value2: UniChar, printDetails: Bool = false) {
let size = count * MemoryLayout<UniChar>.size
let bytes = malloc(size)!
let chars = bytes.assumingMemoryBound(to: UniChar.self)
for i in 0 ..< count {
chars[i] = value1
}
let ns = NSString(charactersNoCopy: chars, length: count, freeWhenDone: false)
let sn = ns as String
let ns1 = "\(ns)"
let sn1 = "\(sn)"
chars.pointee = value2
let ns2 = "\(ns)"
let sn2 = "\(sn)"
if printDetails {
print("ns1: \(ns1)")
print("sn1: \(sn1)")
print("-- modification --")
print("ns2: \(ns2)")
print("sn2: \(sn2)")
}
print("\(testName)\tlen:\(count)\t \tNS:\(neq(ns1,ns2)) \tS(NS):\(neq(sn1,sn2,true))")
}
func test_String_bytes<T>(_ testName: String, count: Int, value1: T, value2: T, encoding: String.Encoding, printDetails: Bool = false) {
let size = count * MemoryLayout<T>.size
let bytes = malloc(size)!
let chars = bytes.assumingMemoryBound(to: T.self)
for i in 0 ..< count {
chars[i] = value1
}
let s = String(bytesNoCopy: bytes, length: size, encoding: encoding, freeWhenDone: false)!
let s1 = "\(s)"
chars.pointee = value2
let s2 = "\(s)"
if printDetails {
print("s1: \(s1)")
print("-- modification --")
print("s2: \(s2)")
}
print("\(testName)\tlen:\(count)\t \t \tS:\(neq(s1,s2,true))")
}
func test_String_chars(_ testName: String, count: Int, value1: unichar, value2: unichar, printDetails: Bool = false) {
let size = count * MemoryLayout<unichar>.size
let bytes = malloc(size)!
let chars = bytes.assumingMemoryBound(to: unichar.self)
for i in 0 ..< count {
chars[i] = value1
}
let s = String(utf16CodeUnitsNoCopy: chars, count: count, freeWhenDone: false)
let s1 = "\(s)"
chars.pointee = value2
let s2 = "\(s)"
if printDetails {
print("s1: \(s1)")
print("-- modification --")
print("s2: \(s2)")
}
print("\(testName)\tlen:\(count)\t \t \tS:\(neq(s1,s2,true))")
}
func test_CFData_bytes(_ testName: String, count: Int, value1: UInt8, value2: UInt8, printDetails: Bool = false) {
let bytes = malloc(count)!
let chars = bytes.assumingMemoryBound(to: UInt8.self)
for i in 0 ..< count {
chars[i] = value1
}
let cf = CFDataCreateWithBytesNoCopy(nil, chars, count, kCFAllocatorNull)!
let ns = cf as NSData
let sc = cf as Data
let sn = ns as Data
let cf1 = "\(cf)"
let ns1 = "\(ns)"
let sc1 = "\(sc.hexString)"
let sn1 = "\(sn.hexString)"
chars.pointee = value2
let cf2 = "\(cf)"
let ns2 = "\(ns)"
let sc2 = "\(sc.hexString)"
let sn2 = "\(sn.hexString)"
if printDetails {
print("cf1: \(cf1)")
print("ns1: \(ns1)")
print("sc1: \(sc1)")
print("sn1: \(sn1)")
print("-- modification --")
print("cf2: \(cf2)")
print("ns2: \(ns2)")
print("sc2: \(sc2)")
print("sn2: \(sn2)")
}
print("\(testName)\tlen:\(count)\tCF:\(neq(cf1,cf2))\tNS(CF):\(neq(ns1,ns2))\tS(CF):\(neq(sc1,sc2,true))\tS(NS):\(neq(sn1,sn2,true))")
}
func test_NSData_bytes(_ testName: String, count: Int, value1: UInt8, value2: UInt8, printDetails: Bool = false) {
let bytes = malloc(count)!
let chars = bytes.assumingMemoryBound(to: UInt8.self)
for i in 0 ..< count {
chars[i] = value1
}
let ns = NSData(bytesNoCopy: bytes, length: count, freeWhenDone: false)
let sn = ns as Data
let ns1 = "\(ns)"
let sn1 = "\(sn.hexString)"
chars.pointee = value2
let ns2 = "\(ns)"
let sn2 = "\(sn.hexString)"
if printDetails {
print("ns1: \(ns1)")
print("sn1: \(sn1)")
print("-- modification --")
print("ns2: \(ns2)")
print("sn2: \(sn2)")
}
print("\(testName)\tlen:\(count)\t \tNS:\(neq(ns1,ns2)) \tS(NS):\(neq(sn1,sn2,true))")
}
func test_Data_bytes(_ testName: String, count: Int, value1: UInt8, value2: UInt8, printDetails: Bool = false) {
let bytes = malloc(count)!
let chars = bytes.assumingMemoryBound(to: UInt8.self)
for i in 0 ..< count {
chars[i] = value1
}
let s = Data(bytesNoCopy: bytes, count: count, deallocator: .none)
let s1 = "\(s.hexString)"
chars.pointee = value2
let s2 = "\(s.hexString)"
if printDetails {
print("s1: \(s1)")
print("-- modification --")
print("s2: \(s2)")
}
print("\(testName)\tlen:\(count)\t \t \tS:\(neq(s1,s2,true))")
}
func test() {
test_CFString_bytes("CFString ascii ", count: 9, value1: UInt8(0x41), value2: UInt8(0x42), encoding: .ASCII)
test_CFString_bytes("CFString ascii ", count: 10, value1: UInt8(0x41), value2: UInt8(0x42), encoding: .ASCII)
test_CFString_bytes("CFString utf8 ", count: 9, value1: UInt8(0x41), value2: UInt8(0x42), encoding: .UTF8)
test_CFString_bytes("CFString utf8 ", count: 10, value1: UInt8(0x41), value2: UInt8(0x42), encoding: .UTF8)
test_CFString_bytes("CFString utf16LE ", count: 1, value1: UInt16(0x41), value2: UInt16(0x42), encoding: .UTF16LE)
test_CFString_bytes("CFString utf16BE ", count: 1, value1: UInt16(0x4100), value2: UInt16(0x4200), encoding: .UTF16BE)
test_CFString_chars("CFString_chars ", count: 1, value1: 0x41, value2: 0x42)
test_NSString_bytes("NSString utf8 ", count: 9, value1: UInt8(0x41), value2: UInt8(0x42), encoding: .utf8)
test_NSString_bytes("NSString utf8 ", count: 10, value1: UInt8(0x41), value2: UInt8(0x42), encoding: .utf8)
test_NSString_bytes("NSString utf16LE ", count: 1, value1: UInt16(0x41), value2: UInt16(0x42), encoding: .utf16LittleEndian)
test_NSString_bytes("NSString utf16BE ", count: 20, value1: UInt16(0x4100), value2: UInt16(0x4200), encoding: .utf16BigEndian)
test_NSString_chars("NSString_chars ", count: 1, value1: 0x41, value2: 0x42)
test_String_bytes( "String utf8 ", count: 20, value1: UInt8(0x41), value2: UInt8(0x42), encoding: .utf8)
test_String_bytes( "String utf16LE ", count: 20, value1: UInt16(0x41), value2: UInt16(0x42), encoding: .utf16LittleEndian)
test_String_chars( "String_chars ", count: 20, value1: 0x41, value2: 0x42)
test_CFData_bytes( "CFData ", count: 14, value1: 0x41, value2: 0x42)
test_CFData_bytes( "CFData ", count: 15, value1: 0x41, value2: 0x42)
test_NSData_bytes( "NSData ", count: 1, value1: 0x41, value2: 0x42)
test_NSData_bytes( "NSData ", count: 20, value1: 0x41, value2: 0x42)
test_Data_bytes( "Data ", count: 14, value1: 0x41, value2: 0x42)
test_Data_bytes( "Data ", count: 15, value1: 0x41, value2: 0x42)
print()
}
func neq<T: Equatable>(_ a: T, _ b: T, _ dangerous: Bool = false) -> String {
(a != b ? "Y" : "N") + (a != b && dangerous ? "*" : " ")
}
extension Data {
var hexString: String {
reduce("") { r, e in
r + String(format: "%02x", e)
}
}
}
test()