[Foundation] add additional conformances and functionality to NSRange

Author: phausler

stdlib/public/SDK/Foundation/NSRange.swift

@@ -12,33 +12,117 @@
 
 @_exported import Foundation // Clang module
 
+extension NSRange : Hashable {
+    public var hashValue: Int { 
+        return Int(bitPattern: UInt(location) ^ UInt(location))
+    }
+
+    public static func==(_ lhs: NSRange, _ rhs: NSRange) -> Bool {
+        return lhs.location == rhs.location && rhs.length == rhs.length
+    }
+}
+
+extension NSRange : CustomStringConvertible, CustomDebugStringConvertible {
+    public var description: String { return "{\(location), \(length)}" }
+    public var debugDescription: String { return "{\(location), \(length)}" }
+}
+
+extension NSRange {
+    public init?(_ string: String) {
+        if string.isEmpty {
+            // fail early if the string is empty
+            return nil
+        }
+        let scanner = Scanner(string: string)
+        let digitSet = CharacterSet.decimalDigits
+        let _ = scanner.scanUpToCharacters(from: digitSet, into: nil)
+        if scanner.isAtEnd {
+            // fail early if there are no decimal digits
+            return nil
+        }
+        var location = 0
+        guard scanner.scanInt(&location) else {
+            return nil
+        }
+        if scanner.isAtEnd {
+            // return early if there are no more characters after the first int in the string
+            return nil
+        }
+        let _ = scanner.scanUpToCharacters(from: digitSet, into: nil)
+        if scanner.isAtEnd {
+            // return early if there are no integer characters after the first int in the string
+            return nil
+        }
+        var length = 0
+        guard scanner.scanInt(&length) else {
+            return nil
+        }
+        
+        self.location = location
+        self.length = length
+    }
+}
+
+extension NSRange {
+    public var lowerBound: Int { return location }
+    
+    public var upperBound: Int { return location + length }
+    
+    public func contains(_ index: Int) -> Bool { return (!(index < location) && (index - location) < length) }
+    
+    public mutating func formUnion(_ other: NSRange) {
+        self = union(other)
+    }
+
+    public func union(_ other: NSRange) -> NSRange {
+        let max1 = location + length
+        let max2 = other.location + other.length
+        let maxend = (max1 < max2) ? max2 : max1
+        let minloc = location < other.location ? location : other.location
+        return NSRange(location: minloc, length: maxend - minloc)
+    }
+
+    public func intersection(_ other: NSRange) -> NSRange? {
+        let max1 = location + length
+        let max2 = other.location + other.length
+        let minend = (max1 < max2) ? max1 : max2
+        if other.location <= location && location < max2 {
+            return NSRange(location: location, length: minend - location)
+        } else if location <= other.location && other.location < max1 {
+            return NSRange(location: other.location, length: minend - other.location);
+        }
+        return nil
+    }
+}
+
+
 //===----------------------------------------------------------------------===//
 // Ranges
 //===----------------------------------------------------------------------===//
 
 extension NSRange {
-  public init(_ x: Range<Int>) {
-    location = x.lowerBound
-    length = x.count
-  }
-
-  // FIXME(ABI)#75 (Conditional Conformance): this API should be an extension on Range.
-  // Can't express it now because the compiler does not support conditional
-  // extensions with type equality constraints.
-  public func toRange() -> Range<Int>? {
-    if location == NSNotFound { return nil }
-    return location..<(location+length)
-  }
+    public init(_ x: Range<Int>) {
+        location = x.lowerBound
+        length = x.count
+    }
+
+    // FIXME(ABI)#75 (Conditional Conformance): this API should be an extension on Range.
+    // Can't express it now because the compiler does not support conditional
+    // extensions with type equality constraints.
+    public func toRange() -> Range<Int>? {
+        if location == NSNotFound { return nil }
+        return location..<(location+length)
+    }
 }
 
 extension NSRange : CustomReflectable {
-  public var customMirror: Mirror {
-    return Mirror(self, children: ["location": location, "length": length])
-  }
+    public var customMirror: Mirror {
+        return Mirror(self, children: ["location": location, "length": length])
+    }
 }
 
 extension NSRange : CustomPlaygroundQuickLookable {
-  public var customPlaygroundQuickLook: PlaygroundQuickLook {
-    return .range(Int64(location), Int64(length))
-  }
+    public var customPlaygroundQuickLook: PlaygroundQuickLook {
+        return .range(Int64(location), Int64(length))
+    }
 }

test/Compatibility/bridging-nsnumber-and-nsvalue.swift.gyb

@@ -45,7 +45,6 @@ extension Equatable {
   }
 }
 extension Hashable { public var hashValue: Int { fatalError("trill hiphy") } }
-extension NSRange: Hashable {}
 extension CGSize: Hashable {}
 extension CGPoint: Hashable {}
 extension CGRect: Hashable {}

test/Constraints/bridging-nsnumber-and-nsvalue.swift.gyb

@@ -29,7 +29,6 @@ coercionTypes = {
     'CGRect',
     'CGPoint',
     'CGSize',
-    'NSRange',
   ],
 }
 }%
@@ -41,7 +40,6 @@ extension Equatable {
   }
 }
 extension Hashable { public var hashValue: Int { fatalError("trill hiphy") } }
-extension NSRange: Hashable {}
 extension CGSize: Hashable {}
 extension CGPoint: Hashable {}
 extension CGRect: Hashable {}