Merge pull request kodecocodes#194 from chris-pilcher/bit-set-swift3

Chris Pilcher · web-flow · commit a603c3381b16 · 2016-09-06T21:23:08.000+12:00
Updating Bit Set to Swift 3
diff --git a/Bit Set/BitSet.playground/Sources/BitSet.swift b/Bit Set/BitSet.playground/Sources/BitSet.swift
@@ -11,7 +11,7 @@ public struct BitSet {
   */
   private let N = 64
   public typealias Word = UInt64
-  private(set) public var words: [Word]
+  fileprivate(set) public var words: [Word]
 
   private let allOnes = ~Word()
 
@@ -22,11 +22,11 @@ public struct BitSet {
 
     // Round up the count to the next multiple of 64.
     let n = (size + (N-1)) / N
-    words = .init(count: n, repeatedValue: 0)
+    words = [Word](repeating: 0, count: n)
   }
 
   /* Converts a bit index into an array index and a mask inside the word. */
-  private func indexOf(i: Int) -> (Int, Word) {
+  private func indexOf(_ i: Int) -> (Int, Word) {
     precondition(i >= 0)
     precondition(i < size)
     let o = i / N
@@ -52,7 +52,7 @@ public struct BitSet {
     that we're not using, or bitwise operations between two differently sized
     BitSets will go wrong.
   */
-  private mutating func clearUnusedBits() {
+  fileprivate mutating func clearUnusedBits() {
     words[words.count - 1] &= lastWordMask()
   }
 
@@ -63,7 +63,7 @@ public struct BitSet {
   }
 
   /* Sets the bit at the specified index to 1. */
-  public mutating func set(i: Int) {
+  public mutating func set(_ i: Int) {
     let (j, m) = indexOf(i)
     words[j] |= m
   }
@@ -77,7 +77,7 @@ public struct BitSet {
   }
 
   /* Sets the bit at the specified index to 0. */
-  public mutating func clear(i: Int) {
+  public mutating func clear(_ i: Int) {
     let (j, m) = indexOf(i)
     words[j] &= ~m
   }
@@ -90,14 +90,14 @@ public struct BitSet {
   }
 
   /* Changes 0 into 1 and 1 into 0. Returns the new value of the bit. */
-  public mutating func flip(i: Int) -> Bool {
+  public mutating func flip(_ i: Int) -> Bool {
     let (j, m) = indexOf(i)
     words[j] ^= m
     return (words[j] & m) != 0
   }
 
   /* Determines whether the bit at the specific index is 1 (true) or 0 (false). */
-  public func isSet(i: Int) -> Bool {
+  public func isSet(_ i: Int) -> Bool {
     let (j, m) = indexOf(i)
     return (words[j] & m) != 0
   }
@@ -158,7 +158,7 @@ extension BitSet: Hashable {
   /* Based on the hashing code from Java's BitSet. */
   public var hashValue: Int {
     var h = Word(1234)
-    for i in words.count.stride(to: 0, by: -1) {
+    for i in stride(from: words.count, to: 0, by: -1) {
       h ^= words[i - 1] &* Word(i)
     }
     return Int((h >> 32) ^ h)
@@ -167,13 +167,13 @@ extension BitSet: Hashable {
 
 // MARK: - Bitwise operations
 
-extension BitSet: BitwiseOperationsType {
+extension BitSet: BitwiseOperations {
   public static var allZeros: BitSet {
     return BitSet(size: 64)
   }
 }
 
-private func copyLargest(lhs: BitSet, _ rhs: BitSet) -> BitSet {
+private func copyLargest(_ lhs: BitSet, _ rhs: BitSet) -> BitSet {
   return (lhs.words.count > rhs.words.count) ? lhs : rhs
 }
 
diff --git a/Bit Set/BitSet.swift b/Bit Set/BitSet.swift
@@ -11,7 +11,7 @@ public struct BitSet {
   */
   private let N = 64
   public typealias Word = UInt64
-  private(set) public var words: [Word]
+  fileprivate(set) public var words: [Word]
 
   private let allOnes = ~Word()
 
@@ -22,11 +22,11 @@ public struct BitSet {
 
     // Round up the count to the next multiple of 64.
     let n = (size + (N-1)) / N
-    words = .init(count: n, repeatedValue: 0)
+    words = [Word](repeating: 0, count: n)
   }
 
   /* Converts a bit index into an array index and a mask inside the word. */
-  private func indexOf(i: Int) -> (Int, Word) {
+  private func indexOf(_ i: Int) -> (Int, Word) {
     precondition(i >= 0)
     precondition(i < size)
     let o = i / N
@@ -52,7 +52,7 @@ public struct BitSet {
     that we're not using, or bitwise operations between two differently sized
     BitSets will go wrong.
   */
-  private mutating func clearUnusedBits() {
+  fileprivate mutating func clearUnusedBits() {
     words[words.count - 1] &= lastWordMask()
   }
 
@@ -63,7 +63,7 @@ public struct BitSet {
   }
 
   /* Sets the bit at the specified index to 1. */
-  public mutating func set(i: Int) {
+  public mutating func set(_ i: Int) {
     let (j, m) = indexOf(i)
     words[j] |= m
   }
@@ -77,7 +77,7 @@ public struct BitSet {
   }
 
   /* Sets the bit at the specified index to 0. */
-  public mutating func clear(i: Int) {
+  public mutating func clear(_ i: Int) {
     let (j, m) = indexOf(i)
     words[j] &= ~m
   }
@@ -90,14 +90,14 @@ public struct BitSet {
   }
 
   /* Changes 0 into 1 and 1 into 0. Returns the new value of the bit. */
-  public mutating func flip(i: Int) -> Bool {
+  public mutating func flip(_ i: Int) -> Bool {
     let (j, m) = indexOf(i)
     words[j] ^= m
     return (words[j] & m) != 0
   }
 
   /* Determines whether the bit at the specific index is 1 (true) or 0 (false). */
-  public func isSet(i: Int) -> Bool {
+  public func isSet(_ i: Int) -> Bool {
     let (j, m) = indexOf(i)
     return (words[j] & m) != 0
   }
@@ -158,7 +158,7 @@ extension BitSet: Hashable {
   /* Based on the hashing code from Java's BitSet. */
   public var hashValue: Int {
     var h = Word(1234)
-    for i in words.count.stride(to: 0, by: -1) {
+    for i in stride(from: words.count, to: 0, by: -1) {
       h ^= words[i - 1] &* Word(i)
     }
     return Int((h >> 32) ^ h)
@@ -167,13 +167,13 @@ extension BitSet: Hashable {
 
 // MARK: - Bitwise operations
 
-extension BitSet: BitwiseOperationsType {
+extension BitSet: BitwiseOperations {
   public static var allZeros: BitSet {
     return BitSet(size: 64)
   }
 }
 
-private func copyLargest(lhs: BitSet, _ rhs: BitSet) -> BitSet {
+private func copyLargest(_ lhs: BitSet, _ rhs: BitSet) -> BitSet {
   return (lhs.words.count > rhs.words.count) ? lhs : rhs
 }
 
diff --git a/Bit Set/README.markdown b/Bit Set/README.markdown
@@ -18,15 +18,15 @@ public struct BitSet {
 
   private let N = 64
   public typealias Word = UInt64
-  private(set) public var words: [Word]
+  fileprivate(set) public var words: [Word]
 
   public init(size: Int) {
     precondition(size > 0)
     self.size = size
 
     // Round up the count to the next multiple of 64.
     let n = (size + (N-1)) / N
-    words = .init(count: n, repeatedValue: 0)
+    words = [Word](repeating: 0, count: n)
   }
 ```
 
@@ -47,7 +47,7 @@ then the `BitSet` allocates an array of three words. Each word has 64 bits and t
 Most of the operations on `BitSet` take the index of the bit as a parameter, so it's useful to have a way to find which word contains that bit.
 
 ```swift
-  private func indexOf(i: Int) -> (Int, Word) {
+  private func indexOf(_ i: Int) -> (Int, Word) {
     precondition(i >= 0)
     precondition(i < size)
     let o = i / N
@@ -77,7 +77,7 @@ Note that the mask is always 64 bits because we look at the data one word at a t
 Now that we know where to find a bit, setting it to 1 is easy:
 
 ```swift
-  public mutating func set(i: Int) {
+  public mutating func set(_ i: Int) {
     let (j, m) = indexOf(i)
     words[j] |= m
   }
@@ -88,7 +88,7 @@ This looks up the word index and the mask, then performs a bitwise OR between th
 Clearing the bit -- i.e. changing it to 0 -- is just as easy:
 
 ```swift
-  public mutating func clear(i: Int) {
+  public mutating func clear(_ i: Int) {
     let (j, m) = indexOf(i)
     words[j] &= ~m
   }
@@ -99,7 +99,7 @@ Instead of a bitwise OR we now do a bitwise AND with the inverse of the mask. So
 To see if a bit is set we also use the bitwise AND but without inverting:
 
 ```swift
-  public func isSet(i: Int) -> Bool {
+  public func isSet(_ i: Int) -> Bool {
     let (j, m) = indexOf(i)
     return (words[j] & m) != 0
   }
@@ -127,15 +127,15 @@ print(bits)
 This will print the three words that the 140-bit `BitSet` uses to store everything:
 
 ```swift
-0010000000000000000000000000000000000000000000000000000000000000 
-0000000000000000000000000000000000010000000000000000000000000000 
-1000000000000000000000000000000000000000000000000000000000000000 
+0010000000000000000000000000000000000000000000000000000000000000
+0000000000000000000000000000000000010000000000000000000000000000
+1000000000000000000000000000000000000000000000000000000000000000
 ```
 
 Something else that's fun to do with bits is flipping them. This changes 0 into 1 and 1 into 0. Here's `flip()`:
 
 ```swift
-  public mutating func flip(i: Int) -> Bool {
+  public mutating func flip(_ i: Int) -> Bool {
     let (j, m) = indexOf(i)
     words[j] ^= m
     return (words[j] & m) != 0
@@ -170,17 +170,17 @@ There is also `setAll()` to make all the bits 1. However, this has to deal with
 First, we copy ones into all the words in our array. The array is now:
 
 ```swift
-1111111111111111111111111111111111111111111111111111111111111111 
-1111111111111111111111111111111111111111111111111111111111111111 
-1111111111111111111111111111111111111111111111111111111111111111 
+1111111111111111111111111111111111111111111111111111111111111111
+1111111111111111111111111111111111111111111111111111111111111111
+1111111111111111111111111111111111111111111111111111111111111111
 ```
 
 But this is incorrect... Since we don't use most of the last word, we should leave those bits at 0:
 
 ```swift
-1111111111111111111111111111111111111111111111111111111111111111 
-1111111111111111111111111111111111111111111111111111111111111111 
-1111111111110000000000000000000000000000000000000000000000000000 
+1111111111111111111111111111111111111111111111111111111111111111
+1111111111111111111111111111111111111111111111111111111111111111
+1111111111110000000000000000000000000000000000000000000000000000
 ```
 
 Instead of 192 one-bits we now have only 140 one-bits. The fact that the last word may not be completely filled up means that we always have to treat this last word specially.
@@ -189,7 +189,7 @@ Setting those "leftover" bits to 0 is what the `clearUnusedBits()` helper functi
 
 This uses some advanced bit manipulation, so pay close attention:
 
-```swift 
+```swift
   private func lastWordMask() -> Word {
     let diff = words.count*N - size       // 1
     if diff > 0 {
@@ -199,7 +199,7 @@ This uses some advanced bit manipulation, so pay close attention:
       return ~Word()
     }
   }
-  
+
   private mutating func clearUnusedBits() {
     words[words.count - 1] &= lastWordMask()   // 4
   }  
@@ -211,15 +211,15 @@ Here's what it does, step-by-step:
 
 2) Create a mask that is all 0's, except the highest bit that's still valid is a 1. In our example, that would be:
 
-	0000000000010000000000000000000000000000000000000000000000000000 
+	0000000000010000000000000000000000000000000000000000000000000000
 
 3) Subtract 1 to turn it into:
 
-	1111111111100000000000000000000000000000000000000000000000000000 
+	1111111111100000000000000000000000000000000000000000000000000000
 
 and add the high bit back in to get:
 
-	1111111111110000000000000000000000000000000000000000000000000000 
+	1111111111110000000000000000000000000000000000000000000000000000
 
 There are now 12 one-bits in this word because `140 - 2*64 = 12`.
 
@@ -236,7 +236,7 @@ The first one only uses the first 4 bits; the second one uses 8 bits. The first
 	00100011  
 	-------- OR
 	10101111
-	
+
 That is wrong since two of those 1-bits aren't supposed to be here. The correct way to do it is:
 
 	10000000       unused bits set to 0 first!
