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@mikeash
Created April 16, 2015 23:33
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class ArrayImpl<T> {
var space: Int
var count: Int
var ptr: UnsafeMutablePointer<T>
init(count: Int = 0, ptr: UnsafeMutablePointer<T> = nil) {
self.count = count
self.space = count
self.ptr = UnsafeMutablePointer<T>.alloc(count)
self.ptr.initializeFrom(ptr, count: count)
}
func append(obj: T) {
if space == count {
let newSpace = max(space * 2, 16)
let newPtr = UnsafeMutablePointer<T>.alloc(newSpace)
newPtr.moveInitializeFrom(ptr, count: count)
ptr.dealloc(count)
ptr = newPtr
space = newSpace
}
(ptr + count).initialize(obj)
count++
}
func remove(# index: Int) {
(ptr + index).destroy()
(ptr + index).moveInitializeFrom(ptr + index + 1, count: count - index - 1)
count--
}
func copy() -> ArrayImpl<T> {
return ArrayImpl<T>(count: count, ptr: ptr)
}
deinit {
ptr.destroy(count)
ptr.dealloc(count)
}
}
struct Array<T>: Printable, CollectionType {
private var impl: ArrayImpl<T> = ArrayImpl<T>()
private mutating func ensureUnique() {
if !isUniquelyReferencedNonObjC(&impl) {
impl = impl.copy()
}
}
mutating func append(value: T) {
ensureUnique()
impl.append(value)
}
mutating func remove(# index: Int) {
ensureUnique()
impl.remove(index: index)
}
var count: Int {
return impl.count
}
subscript(index: Int) -> T {
get {
return impl.ptr[index]
}
mutating set {
ensureUnique()
impl.ptr[index] = newValue
}
}
var description: String {
var str = ""
for value in self {
if !str.isEmpty {
str += ", "
}
str += toString(value)
}
return "(\(impl.ptr): " + str + ")"
}
typealias Index = Int
var startIndex: Index {
return 0
}
var endIndex: Index {
return count
}
typealias Generator = GeneratorOf<T>
func generate() -> Generator {
var index = 0
return GeneratorOf<T>{
if index < self.count {
return self[index++]
} else {
return nil
}
}
}
}
var array = Array<Int>()
var array2 = array
println((array, array2))
array.append(42)
array2.append(99)
array2.append(43)
println((array, array2))
var array3 = array2
array2[0] = 1
array3[0] = 0
println((array2, array3))
array3.remove(index: 1)
array3.remove(index: 0)
println(array3)
var array4 = Array<Int>()
for i in 0..<100 {
array4.append(i)
}
var array5 = array4
while array4.count > 3 {
array4.remove(index: 1)
}
println((array4, array5))
var strarray = Array<String>()
strarray.append("e")
for i in 0..<100 {
strarray.append("\(i)")
}
println(strarray)
var strarray2 = strarray
while strarray.count > 4 {
strarray.remove(index: 3)
}
while strarray2.count > 4 {
strarray2.remove(index: strarray2.count - 1)
}
println((strarray, strarray2))
for s in strarray {
println(s)
}
@alonecuzzo
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👍

@ttilley
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ttilley commented Sep 14, 2015

don't you want to dealloc space, not count?

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