stdlib: move _BitMap to its own file

Author: gribozavr

stdlib/public/core/CMakeLists.txt

@@ -114,6 +114,7 @@ set(SWIFTLIB_ESSENTIAL
   UnicodeScalar.swift
   UnicodeTrie.swift.gyb
   Unmanaged.swift
+  UnsafeBitMap.swift
   UnsafeBufferPointer.swift.gyb
   UnsafePointer.swift.gyb
   WriteBackMutableSlice.swift

stdlib/public/core/GroupInfo.json

@@ -140,5 +140,6 @@
     "Process.swift",
     "Tuple.swift",
     "NewtypeWrapper.swift",
+    "UnsafeBitMap.swift"
   ]
 }

stdlib/public/core/HashedCollections.swift.gyb

@@ -2455,60 +2455,6 @@ collections = [
 ]
 }%
 
-/// A wrapper around a bitmap storage with room for at least `bitCount` bits.
-internal struct _BitMap {
-  internal let values: UnsafeMutablePointer<UInt>
-  internal let bitCount: Int
-
-  internal static func wordIndex(_ i: Int) -> Int {
-    // Note: We perform the operation on UInts to get faster unsigned math
-    // (shifts).
-    return Int(bitPattern: UInt(bitPattern: i) / UInt(UInt._sizeInBits))
-  }
-
-  internal static func bitIndex(_ i: Int) -> UInt {
-    // Note: We perform the operation on UInts to get faster unsigned math
-    // (shifts).
-    return UInt(bitPattern: i) % UInt(UInt._sizeInBits)
-  }
-
-  internal static func sizeInWords(forCapacity bitCount: Int) -> Int {
-    return bitCount + Int._sizeInBytes - 1 / Int._sizeInBytes
-  }
-
-  internal init(storage: UnsafeMutablePointer<UInt>, bitCount: Int) {
-    self.bitCount = bitCount
-    self.values = storage
-  }
-
-  internal var numberOfWords: Int {
-    return _BitMap.sizeInWords(forCapacity: bitCount)
-  }
-
-  internal func initializeToZero() {
-    values.initialize(with: 0, count: numberOfWords)
-  }
-
-  internal subscript(i: Int) -> Bool {
-    get {
-      _sanityCheck(i < Int(bitCount) && i >= 0, "index out of bounds")
-      let word = values[_BitMap.wordIndex(i)]
-      let bit = word & (1 << _BitMap.bitIndex(i))
-      return bit != 0
-    }
-    nonmutating set {
-      _sanityCheck(i < Int(bitCount) && i >= 0, "index out of bounds")
-      let wordIdx = _BitMap.wordIndex(i)
-      let bitMask = 1 << _BitMap.bitIndex(i)
-      if newValue {
-        values[wordIdx] = values[wordIdx] | bitMask
-      } else {
-        values[wordIdx] = values[wordIdx] & ~bitMask
-      }
-    }
-  }
-}
-
 /// Header part of the native storage.
 internal struct _HashedContainerStorageHeader {
   internal init(capacity: Int) {

stdlib/public/core/UnsafeBitMap.swift

@@ -0,0 +1,66 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2016 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See http://swift.org/LICENSE.txt for license information
+// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+/// A wrapper around a bitmap storage with room for at least `bitCount` bits.
+internal struct _BitMap {
+  internal let values: UnsafeMutablePointer<UInt>
+  internal let bitCount: Int
+
+  internal static func wordIndex(_ i: Int) -> Int {
+    // Note: We perform the operation on UInts to get faster unsigned math
+    // (shifts).
+    return Int(bitPattern: UInt(bitPattern: i) / UInt(UInt._sizeInBits))
+  }
+
+  internal static func bitIndex(_ i: Int) -> UInt {
+    // Note: We perform the operation on UInts to get faster unsigned math
+    // (shifts).
+    return UInt(bitPattern: i) % UInt(UInt._sizeInBits)
+  }
+
+  internal static func sizeInWords(forCapacity bitCount: Int) -> Int {
+    return bitCount + Int._sizeInBytes - 1 / Int._sizeInBytes
+  }
+
+  internal init(storage: UnsafeMutablePointer<UInt>, bitCount: Int) {
+    self.bitCount = bitCount
+    self.values = storage
+  }
+
+  internal var numberOfWords: Int {
+    return _BitMap.sizeInWords(forCapacity: bitCount)
+  }
+
+  internal func initializeToZero() {
+    values.initialize(with: 0, count: numberOfWords)
+  }
+
+  internal subscript(i: Int) -> Bool {
+    get {
+      _sanityCheck(i < Int(bitCount) && i >= 0, "index out of bounds")
+      let word = values[_BitMap.wordIndex(i)]
+      let bit = word & (1 << _BitMap.bitIndex(i))
+      return bit != 0
+    }
+    nonmutating set {
+      _sanityCheck(i < Int(bitCount) && i >= 0, "index out of bounds")
+      let wordIdx = _BitMap.wordIndex(i)
+      let bitMask = 1 << _BitMap.bitIndex(i)
+      if newValue {
+        values[wordIdx] = values[wordIdx] | bitMask
+      } else {
+        values[wordIdx] = values[wordIdx] & ~bitMask
+      }
+    }
+  }
+}
+