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Decimal.init(sign:exponent:significand:) should clamp exponent #747

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Merged
merged 1 commit into from
Jul 19, 2024
Merged

Decimal.init(sign:exponent:significand:) should clamp exponent #747

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14 changes: 7 additions & 7 deletions Sources/FoundationEssentials/Decimal/Decimal+Conformances.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -17,12 +17,12 @@ internal import _ForSwiftFoundation
@available(macOS 10.10, iOS 8.0, watchOS 2.0, tvOS 9.0, *)
extension Decimal : CustomStringConvertible {
public init?(string: __shared String, locale: __shared Locale? = nil) {
// Substitute the decimal sign if needed
var decimalString = string
if let decimalSeparator = locale?.decimalSeparator {
decimalString = decimalString.replacing(decimalSeparator, with: ".")
}
guard let value = Decimal.decimal(from: decimalString.utf8, matchEntireString: false).result else {
let decimalSeparator = locale?.decimalSeparator ?? "."
guard let value = Decimal.decimal(
from: string.utf8,
decimalSeparator: decimalSeparator.utf8,
matchEntireString: false
).result else {
return nil
}
self = value
Expand Down Expand Up @@ -239,7 +239,7 @@ extension Decimal /* : FloatingPoint */ {
self = significand
do {
self = try significand._multiplyByPowerOfTen(
power: exponent, roundingMode: .plain)
power: Int(Int16(clamping: exponent)), roundingMode: .plain)
} catch {
guard let actual = error as? Decimal._CalculationError else {
self = .nan
Expand Down
19 changes: 17 additions & 2 deletions Sources/FoundationEssentials/Decimal/Decimal.swift
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Expand Up @@ -223,6 +223,7 @@ extension Decimal {

internal static func decimal(
from stringView: String.UTF8View,
decimalSeparator: String.UTF8View,
matchEntireString: Bool
) -> (result: Decimal?, processedLength: Int) {
func multiplyBy10AndAdd(
Expand All @@ -247,6 +248,20 @@ extension Decimal {
return i
}

func stringViewContainsDecimalSeparator(at index: String.UTF8View.Index) -> Bool {
for indexOffset in 0 ..< decimalSeparator.count {
let stringIndex = stringView.index(index, offsetBy: indexOffset)
let decimalIndex = decimalSeparator.index(
decimalSeparator.startIndex,
offsetBy: indexOffset
)
if stringView[stringIndex] != decimalSeparator[decimalIndex] {
return false
}
}
return true
}

var result = Decimal()
var index = stringView.startIndex
index = skipWhiteSpaces(from: index)
Expand Down Expand Up @@ -298,8 +313,8 @@ extension Decimal {
result = product
}
// Get the decimal point
if index != stringView.endIndex && stringView[index] == UInt8._period {
stringView.formIndex(after: &index)
if index != stringView.endIndex && stringViewContainsDecimalSeparator(at: index) {
stringView.formIndex(&index, offsetBy: decimalSeparator.count)
// Continue to build the mantissa
while index != stringView.endIndex,
let digitValue = stringView[index].digitValue {
Expand Down
4 changes: 3 additions & 1 deletion Sources/FoundationEssentials/JSON/JSONDecoder.swift
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Expand Up @@ -1075,7 +1075,9 @@ extension FixedWidthInteger {
extension Decimal {
init?(entire string: String) {
guard let value = Decimal.decimal(
from: string.utf8, matchEntireString: true
from: string.utf8,
decimalSeparator: ".".utf8,
matchEntireString: true
).result else {
return nil
}
Expand Down
188 changes: 185 additions & 3 deletions Tests/FoundationEssentialsTests/DecimalTests.swift
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Expand Up @@ -109,6 +109,15 @@ final class DecimalTests : XCTestCase {
XCTAssertEqual("-5", Decimal(signOf: Decimal(-3), magnitudeOf: Decimal(-5)).description)
}

func test_DescriptionWithLocale() {
let decimal = Decimal(string: "-123456.789")!
XCTAssertEqual(decimal.toString(with: nil), "-123456.789")
let en = decimal.toString(with: Locale(identifier: "en_GB"))
XCTAssertEqual(en, "-123456.789")
let fr = decimal.toString(with: Locale(identifier: "fr_FR"))
XCTAssertEqual(fr, "-123456,789")
}

func test_BasicConstruction() {
let zero = Decimal()
XCTAssertEqual(20, MemoryLayout<Decimal>.size)
Expand Down Expand Up @@ -252,6 +261,57 @@ final class DecimalTests : XCTestCase {
XCTAssertEqual(zero3.description, "0")
}

func test_stringWithLocale() {

let en_US = Locale(identifier: "en_US")
let fr_FR = Locale(identifier: "fr_FR")

XCTAssertEqual(Decimal(string: "1,234.56")! * 1000, Decimal(1000))
XCTAssertEqual(Decimal(string: "1,234.56", locale: en_US)! * 1000, Decimal(1000))
XCTAssertEqual(Decimal(string: "1,234.56", locale: fr_FR)! * 1000, Decimal(1234))
XCTAssertEqual(Decimal(string: "1.234,56", locale: en_US)! * 1000, Decimal(1234))
XCTAssertEqual(Decimal(string: "1.234,56", locale: fr_FR)! * 1000, Decimal(1000))

XCTAssertEqual(Decimal(string: "-1,234.56")! * 1000, Decimal(-1000))
XCTAssertEqual(Decimal(string: "+1,234.56")! * 1000, Decimal(1000))
XCTAssertEqual(Decimal(string: "+1234.56e3"), Decimal(1234560))
XCTAssertEqual(Decimal(string: "+1234.56E3"), Decimal(1234560))
XCTAssertEqual(Decimal(string: "+123456000E-3"), Decimal(123456))

XCTAssertNil(Decimal(string: ""))
XCTAssertNil(Decimal(string: "x"))
XCTAssertEqual(Decimal(string: "-x"), Decimal.zero)
XCTAssertEqual(Decimal(string: "+x"), Decimal.zero)
XCTAssertEqual(Decimal(string: "-"), Decimal.zero)
XCTAssertEqual(Decimal(string: "+"), Decimal.zero)
XCTAssertEqual(Decimal(string: "-."), Decimal.zero)
XCTAssertEqual(Decimal(string: "+."), Decimal.zero)

XCTAssertEqual(Decimal(string: "-0"), Decimal.zero)
XCTAssertEqual(Decimal(string: "+0"), Decimal.zero)
XCTAssertEqual(Decimal(string: "-0."), Decimal.zero)
XCTAssertEqual(Decimal(string: "+0."), Decimal.zero)
XCTAssertEqual(Decimal(string: "e1"), Decimal.zero)
XCTAssertEqual(Decimal(string: "e-5"), Decimal.zero)
XCTAssertEqual(Decimal(string: ".3e1"), Decimal(3))

XCTAssertEqual(Decimal(string: "."), Decimal.zero)
XCTAssertEqual(Decimal(string: ".", locale: en_US), Decimal.zero)
XCTAssertNil(Decimal(string: ".", locale: fr_FR))

XCTAssertNil(Decimal(string: ","))
XCTAssertEqual(Decimal(string: ",", locale: fr_FR), Decimal.zero)
XCTAssertNil(Decimal(string: ",", locale: en_US))

let s1 = "1234.5678"
XCTAssertEqual(Decimal(string: s1, locale: en_US)?.description, s1)
XCTAssertEqual(Decimal(string: s1, locale: fr_FR)?.description, "1234")

let s2 = "1234,5678"
XCTAssertEqual(Decimal(string: s2, locale: en_US)?.description, "1234")
XCTAssertEqual(Decimal(string: s2, locale: fr_FR)?.description, s1)
}

func testStringPartialMatch() {
// This tests makes sure Decimal still has the
// same behavior that it only requires the beginning
Expand Down Expand Up @@ -736,6 +796,37 @@ final class DecimalTests : XCTestCase {
XCTAssertEqual(-4.98, result.doubleValue, accuracy: 0.0001)
}

func test_Round() throws {
let testCases: [(Double, Double, Int, Decimal.RoundingMode)] = [
// expected, start, scale, round
( 0, 0.5, 0, .down ),
( 1, 0.5, 0, .up ),
( 2, 2.5, 0, .bankers ),
( 4, 3.5, 0, .bankers ),
( 5, 5.2, 0, .plain ),
( 4.5, 4.5, 1, .down ),
( 5.5, 5.5, 1, .up ),
( 6.5, 6.5, 1, .plain ),
( 7.5, 7.5, 1, .bankers ),

( -1, -0.5, 0, .down ),
( -2, -2.5, 0, .up ),
( -2, -2.5, 0, .bankers ),
( -4, -3.5, 0, .bankers ),
( -5, -5.2, 0, .plain ),
( -4.5, -4.5, 1, .down ),
( -5.5, -5.5, 1, .up ),
( -6.5, -6.5, 1, .plain ),
( -7.5, -7.5, 1, .bankers ),
]
for testCase in testCases {
let (expected, start, scale, mode) = testCase
let num = Decimal(start)
let actual = try num._round(scale: scale, roundingMode: mode)
XCTAssertEqual(Decimal(expected), actual, "Failed test case: \(testCase)")
}
}

func test_Maths() {
for i in -2...10 {
for j in 0...5 {
Expand Down Expand Up @@ -767,6 +858,25 @@ final class DecimalTests : XCTestCase {
}
}
}

XCTAssertEqual(Decimal(186243 * 15673 as Int64), Decimal(186243) * Decimal(15673))

XCTAssertEqual(Decimal(string: "5538")! + Decimal(string: "2880.4")!, Decimal(string: "8418.4")!)

XCTAssertEqual(Decimal(string: "5538.0")! - Decimal(string: "2880.4")!, Decimal(string: "2657.6")!)
XCTAssertEqual(Decimal(string: "2880.4")! - Decimal(5538), Decimal(string: "-2657.6")!)
XCTAssertEqual(Decimal(0x10000) - Decimal(0x1000), Decimal(0xf000))
#if !os(watchOS)
XCTAssertEqual(Decimal(0x1_0000_0000) - Decimal(0x1000), Decimal(0xFFFFF000))
XCTAssertEqual(Decimal(0x1_0000_0000_0000) - Decimal(0x1000), Decimal(0xFFFFFFFFF000))
#endif
XCTAssertEqual(Decimal(1234_5678_9012_3456_7899 as UInt64) - Decimal(1234_5678_9012_3456_7890 as UInt64), Decimal(9))
XCTAssertEqual(Decimal(0xffdd_bb00_8866_4422 as UInt64) - Decimal(0x7777_7777), Decimal(0xFFDD_BB00_10EE_CCAB as UInt64))

let highBit = Decimal(_exponent: 0, _length: 8, _isNegative: 0, _isCompact: 1, _reserved: 0, _mantissa: (0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x8000))
let otherBits = Decimal(_exponent: 0, _length: 8, _isNegative: 0, _isCompact: 1, _reserved: 0, _mantissa: (0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0x7fff))
XCTAssertEqual(highBit - otherBits, Decimal(1))
XCTAssertEqual(otherBits + Decimal(1), highBit)
}

func testMisc() throws {
Expand Down Expand Up @@ -805,6 +915,67 @@ final class DecimalTests : XCTestCase {
XCTAssertTrue(Decimal.nan.magnitude.isNaN)
XCTAssertEqual(Decimal.leastFiniteMagnitude.magnitude, -Decimal.leastFiniteMagnitude)

XCTAssertEqual(Decimal(-9), Decimal(1) - Decimal(10))
XCTAssertEqual(Decimal(1.234), abs(Decimal(1.234)))
XCTAssertEqual(Decimal(1.234), abs(Decimal(-1.234)))
XCTAssertEqual((0 as Decimal).magnitude, 0 as Decimal)
XCTAssertEqual((1 as Decimal).magnitude, 1 as Decimal)
XCTAssertEqual((1 as Decimal).magnitude, abs(1 as Decimal))
XCTAssertEqual((1 as Decimal).magnitude, abs(-1 as Decimal))
XCTAssertEqual((-1 as Decimal).magnitude, abs(-1 as Decimal))
XCTAssertEqual((-1 as Decimal).magnitude, abs(1 as Decimal))
XCTAssertEqual(Decimal.greatestFiniteMagnitude.magnitude, Decimal.greatestFiniteMagnitude)

var a = Decimal(1234)
var result = try a._multiplyByPowerOfTen(power: 1, roundingMode: .plain)
XCTAssertEqual(Decimal(12340), result)
a = Decimal(1234)
result = try a._multiplyByPowerOfTen(power: 2, roundingMode: .plain)
XCTAssertEqual(Decimal(123400), result)
a = result
do {
result = try a._multiplyByPowerOfTen(power: 128, roundingMode: .plain)
XCTFail("Expected to throw _CalcuationError.overflow")
} catch {
guard let calculationError = error as? Decimal._CalculationError else {
XCTFail("Expected Decimal._CalculationError, got \(error)")
return
}
XCTAssertEqual(.overflow, calculationError)
}
a = Decimal(1234)
result = try a._multiplyByPowerOfTen(power: -2, roundingMode: .plain)
XCTAssertEqual(Decimal(12.34), result)
a = result
do {
result = try a._multiplyByPowerOfTen(power: -128, roundingMode: .plain)
XCTFail("Expected to throw _CalcuationError.underflow")
} catch {
guard let calculationError = error as? Decimal._CalculationError else {
XCTFail("Expected Decimal._CalculationError, got \(error)")
return
}
XCTAssertEqual(.underflow, calculationError)
}
a = Decimal(1234)
result = try a._power(exponent: 0, roundingMode: .plain)
XCTAssertEqual(Decimal(1), result)
a = Decimal(8)
result = try a._power(exponent: 2, roundingMode: .plain)
XCTAssertEqual(Decimal(64), result)
a = Decimal(-2)
result = try a._power(exponent: 3, roundingMode: .plain)
XCTAssertEqual(Decimal(-8), result)
for i in -2...10 {
for j in 0...5 {
let power = Decimal(i)
let actual = try power._power(exponent: UInt(j), roundingMode: .plain)
let expected = Decimal(pow(Double(i), Double(j)))
XCTAssertEqual(expected, actual, "\(actual) == \(i)^\(j)")
XCTAssertEqual(expected, try power._power(exponent: UInt(j), roundingMode: .plain))
}
}

do {
// SR-13015
let a = try XCTUnwrap(Decimal(string: "119.993"))
Expand Down Expand Up @@ -946,15 +1117,26 @@ final class DecimalTests : XCTestCase {
}

func test_Significand() {
let x = -42 as Decimal
var x = -42 as Decimal
XCTAssertEqual(x.significand.sign, .plus)
var y = Decimal(sign: .plus, exponent: 0, significand: x)
XCTAssertEqual(y, -42)
y = Decimal(sign: .minus, exponent: 0, significand: x)
XCTAssertEqual(y, 42)

x = 42 as Decimal
XCTAssertEqual(x.significand.sign, .plus)
let y = Decimal(sign: .plus, exponent: 0, significand: x)
XCTAssertEqual(y.sign, .minus)
y = Decimal(sign: .plus, exponent: 0, significand: x)
XCTAssertEqual(y, 42)
y = Decimal(sign: .minus, exponent: 0, significand: x)
XCTAssertEqual(y, -42)

let a = Decimal.leastNonzeroMagnitude
XCTAssertEqual(Decimal(sign: .plus, exponent: -10, significand: a), 0)
XCTAssertEqual(Decimal(sign: .plus, exponent: .min, significand: a), 0)
let b = Decimal.greatestFiniteMagnitude
XCTAssertTrue(Decimal(sign: .plus, exponent: 10, significand: b).isNaN)
XCTAssertTrue(Decimal(sign: .plus, exponent: .max, significand: b).isNaN)
}

func test_ULP() {
Expand Down