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Update NSScanner to use BinaryFloatingPoint #631

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Merged
merged 3 commits into from
Sep 13, 2016
Merged

Update NSScanner to use BinaryFloatingPoint #631

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9e1bc68
Update NSScanner to use BinaryFloatingPoint
xwu Sep 13, 2016
eda6740
Make another fix and add test [NSScanner]
xwu Sep 13, 2016
596cab2
Fixup typos [TestNSScanner]
xwu Sep 13, 2016
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39 changes: 7 additions & 32 deletions Foundation/NSScanner.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -224,37 +224,12 @@ internal protocol _IntegerLike : Integer, _BitShiftable {
static var min: Self { get }
}

internal protocol _FloatArithmeticType {
static func +(lhs: Self, rhs: Self) -> Self
static func -(lhs: Self, rhs: Self) -> Self
static func *(lhs: Self, rhs: Self) -> Self
static func /(lhs: Self, rhs: Self) -> Self
}

internal protocol _FloatLike : FloatingPoint, _FloatArithmeticType {
init(_ value: Int)
init(_ value: Double)
static var max: Self { get }
static var min: Self { get }
}

extension Int : _IntegerLike { }
extension Int32 : _IntegerLike { }
extension Int64 : _IntegerLike { }
extension UInt32 : _IntegerLike { }
extension UInt64 : _IntegerLike { }

// these might be good to have in the stdlib
extension Float : _FloatLike {
static var max: Float { return FLT_MAX }
static var min: Float { return FLT_MIN }
}

extension Double : _FloatLike {
static var max: Double { return DBL_MAX }
static var min: Double { return DBL_MIN }
}

private func numericValue(_ ch: unichar) -> Int {
if (ch >= unichar(unicodeScalarLiteral: "0") && ch <= unichar(unicodeScalarLiteral: "9")) {
return Int(ch) - Int(unichar(unicodeScalarLiteral: "0"))
Expand Down Expand Up @@ -366,7 +341,7 @@ extension String {
return true
}

internal func scan<T: _FloatLike>(_ skipSet: CharacterSet?, locale: Locale?, locationToScanFrom: inout Int, to: (T) -> Void) -> Bool {
internal func scan<T: BinaryFloatingPoint>(_ skipSet: CharacterSet?, locale: Locale?, locationToScanFrom: inout Int, to: (T) -> Void) -> Bool {
let ds_chars = decimalSep(locale).utf16
let ds = ds_chars[ds_chars.startIndex]
var buf = _NSStringBuffer(string: self, start: locationToScanFrom, end: length)
Expand All @@ -388,13 +363,13 @@ extension String {
if numeral == -1 {
break
}
// if (localResult >= T.max / T(10)) && ((localResult > T.max / T(10)) || T(numericValue(buf.currentCharacter) - (neg ? 1 : 0)) >= T.max - localResult * T(10)) is evidently too complex; so break it down to more "edible chunks"
let limit1 = localResult >= T.max / T(10)
let limit2 = localResult > T.max / T(10)
let limit3 = T(numeral - (neg ? 1 : 0)) >= T.max - localResult * T(10)
// if (localResult >= T.greatestFiniteMagnitude / T(10)) && ((localResult > T.greatestFiniteMagnitude / T(10)) || T(numericValue(buf.currentCharacter) - (neg ? 1 : 0)) >= T.greatestFiniteMagnitude - localResult * T(10)) is evidently too complex; so break it down to more "edible chunks"
let limit1 = localResult >= T.greatestFiniteMagnitude / T(10)
let limit2 = localResult > T.greatestFiniteMagnitude / T(10)
let limit3 = T(numeral - (neg ? 1 : 0)) >= T.greatestFiniteMagnitude - localResult * T(10)
if (limit1) && (limit2 || limit3) {
// apply the clamps and advance past the ending of the buffer where there are still digits
localResult = neg ? T.min : T.max
localResult = neg ? -T.infinity : T.infinity
neg = false
repeat {
buf.advance()
Expand Down Expand Up @@ -425,7 +400,7 @@ extension String {
return true
}

internal func scanHex<T: _FloatLike>(_ skipSet: CharacterSet?, locale: Locale?, locationToScanFrom: inout Int, to: (T) -> Void) -> Bool {
internal func scanHex<T: BinaryFloatingPoint>(_ skipSet: CharacterSet?, locale: Locale?, locationToScanFrom: inout Int, to: (T) -> Void) -> Bool {
NSUnimplemented()
}
}
Expand Down
8 changes: 8 additions & 0 deletions TestFoundation/TestNSScanner.swift
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Expand Up @@ -24,6 +24,7 @@ class TestNSScanner : XCTestCase {
static var allTests: [(String, (TestNSScanner) -> () throws -> Void)] {
return [
("test_scanInteger", test_scanInteger),
("test_scanFloat", test_scanFloat),
]
}

Expand All @@ -33,4 +34,11 @@ class TestNSScanner : XCTestCase {
XCTAssert(scanner.scanInteger(&value), "An Integer should be found in the string `123`.")
XCTAssertEqual(value, 123, "Scanned Integer value of the string `123` should be `123`.")
}

func test_scanFloat() {
let scanner = Scanner(string: "-350000000000000000000000000000000000000000")
var value: Float = 0
XCTAssert(scanner.scanFloat(&value), "A Float should be found in the string `-350000000000000000000000000000000000000000`.")
XCTAssert(value.isInfinite, "Scanned Float value of the string `-350000000000000000000000000000000000000000` should be infinite`.")
}
}