Merge pull request #3074 from xwu/decimal-significand-again

xwu · web-flow · commit ac4445d54829 · 2021-09-04T18:54:35.000-04:00
[SR-15156] Another fix for `Decimal(sign:exponent:significand:)`.
diff --git a/Darwin/Foundation-swiftoverlay-Tests/TestDecimal.swift b/Darwin/Foundation-swiftoverlay-Tests/TestDecimal.swift
@@ -580,8 +580,10 @@ class TestDecimal : XCTestCase {
 
         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_SimpleMultiplication() {
diff --git a/Darwin/Foundation-swiftoverlay/Decimal.swift b/Darwin/Foundation-swiftoverlay/Decimal.swift
@@ -519,7 +519,7 @@ extension Decimal {
     public init(sign: FloatingPointSign, exponent: Int, significand: Decimal) {
         self = significand
         let error = withUnsafeMutablePointer(to: &self) {
-            NSDecimalMultiplyByPowerOf10($0, $0, Int16(exponent), .plain)
+            NSDecimalMultiplyByPowerOf10($0, $0, Int16(clamping: exponent), .plain)
         }
         if error == .underflow { self = 0 }
         // We don't need to check for overflow because `Decimal` cannot represent infinity.
diff --git a/Sources/Foundation/Decimal.swift b/Sources/Foundation/Decimal.swift
@@ -687,7 +687,7 @@ extension Decimal {
     public init(sign: FloatingPointSign, exponent: Int, significand: Decimal) {
         self = significand
         let error = withUnsafeMutablePointer(to: &self) {
-            NSDecimalMultiplyByPowerOf10($0, $0, Int16(exponent), .plain)
+            NSDecimalMultiplyByPowerOf10($0, $0, Int16(clamping: exponent), .plain)
         }
         if error == .underflow { self = 0 }
         // We don't need to check for overflow because `Decimal` cannot represent infinity.
diff --git a/Tests/Foundation/Tests/TestDecimal.swift b/Tests/Foundation/Tests/TestDecimal.swift
@@ -821,8 +821,10 @@ class TestDecimal: XCTestCase {
 
         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_SimpleMultiplication() {

Original file line number	Diff line number	Diff line change
`@@ -580,8 +580,10 @@ class TestDecimal : XCTestCase {`
`580`	`580`
`581`	`581`	`let a = Decimal.leastNonzeroMagnitude`
`582`	`582`	`XCTAssertEqual(Decimal(sign: .plus, exponent: -10, significand: a), 0)`
	`583`	`+ XCTAssertEqual(Decimal(sign: .plus, exponent: .min, significand: a), 0)`
`583`	`584`	`let b = Decimal.greatestFiniteMagnitude`
`584`	`585`	`XCTAssertTrue(Decimal(sign: .plus, exponent: 10, significand: b).isNaN)`
	`586`	`+ XCTAssertTrue(Decimal(sign: .plus, exponent: .max, significand: b).isNaN)`
`585`	`587`	`}`
`586`	`588`
`587`	`589`	`func test_SimpleMultiplication() {`
Original file line number	Diff line number	Diff line change
`@@ -519,7 +519,7 @@ extension Decimal {`
`519`	`519`	`public init(sign: FloatingPointSign, exponent: Int, significand: Decimal) {`
`520`	`520`	`self = significand`
`521`	`521`	`let error = withUnsafeMutablePointer(to: &self) {`
`522`		`- NSDecimalMultiplyByPowerOf10($0, $0, Int16(exponent), .plain)`
	`522`	`+ NSDecimalMultiplyByPowerOf10($0, $0, Int16(clamping: exponent), .plain)`
`523`	`523`	`}`
`524`	`524`	`if error == .underflow { self = 0 }`
`525`	`525`	// We don't need to check for overflow because `Decimal` cannot represent infinity.
Original file line number	Diff line number	Diff line change
`@@ -687,7 +687,7 @@ extension Decimal {`
`687`	`687`	`public init(sign: FloatingPointSign, exponent: Int, significand: Decimal) {`
`688`	`688`	`self = significand`
`689`	`689`	`let error = withUnsafeMutablePointer(to: &self) {`
`690`		`- NSDecimalMultiplyByPowerOf10($0, $0, Int16(exponent), .plain)`
	`690`	`+ NSDecimalMultiplyByPowerOf10($0, $0, Int16(clamping: exponent), .plain)`
`691`	`691`	`}`
`692`	`692`	`if error == .underflow { self = 0 }`
`693`	`693`	// We don't need to check for overflow because `Decimal` cannot represent infinity.
Original file line number	Diff line number	Diff line change
`@@ -821,8 +821,10 @@ class TestDecimal: XCTestCase {`
`821`	`821`
`822`	`822`	`let a = Decimal.leastNonzeroMagnitude`
`823`	`823`	`XCTAssertEqual(Decimal(sign: .plus, exponent: -10, significand: a), 0)`
	`824`	`+ XCTAssertEqual(Decimal(sign: .plus, exponent: .min, significand: a), 0)`
`824`	`825`	`let b = Decimal.greatestFiniteMagnitude`
`825`	`826`	`XCTAssertTrue(Decimal(sign: .plus, exponent: 10, significand: b).isNaN)`
	`827`	`+ XCTAssertTrue(Decimal(sign: .plus, exponent: .max, significand: b).isNaN)`
`826`	`828`	`}`
`827`	`829`
`828`	`830`	`func test_SimpleMultiplication() {`