Fix Float32 decoding, add DoubleBox (CoreOffice#138)

Resolve CoreOffice#130.

Also make `xmlString` function a computed property.

Sources/XMLCoder/Auxiliaries/Box/BoolBox.swift

@@ -38,7 +38,7 @@ extension BoolBox: Box {
     /// ---
     ///
     /// [Schema definition](https://www.w3.org/TR/xmlschema-2/#boolean)
-    func xmlString() -> String? {
+    var xmlString: String? {
         return (unboxed) ? "true" : "false"
     }
 }

Sources/XMLCoder/Auxiliaries/Box/Box.swift

@@ -7,7 +7,7 @@
 
 protocol Box {
     var isNull: Bool { get }
-    func xmlString() -> String?
+    var xmlString: String? { get }
 }
 
 /// A box that only describes a single atomic value.

Sources/XMLCoder/Auxiliaries/Box/ChoiceBox.swift

@@ -16,7 +16,7 @@ extension ChoiceBox: Box {
         return false
     }
 
-    func xmlString() -> String? {
+    var xmlString: String? {
         return nil
     }
 }

Sources/XMLCoder/Auxiliaries/Box/DataBox.swift

@@ -42,7 +42,7 @@ extension DataBox: Box {
         return false
     }
 
-    func xmlString() -> String? {
+    var xmlString: String? {
         return xmlString(format: format)
     }
 }

Sources/XMLCoder/Auxiliaries/Box/DateBox.swift

@@ -84,7 +84,7 @@ extension DateBox: Box {
         return false
     }
 
-    func xmlString() -> String? {
+    var xmlString: String? {
         return xmlString(format: format)
     }
 }

Sources/XMLCoder/Auxiliaries/Box/DecimalBox.swift

@@ -47,7 +47,7 @@ extension DecimalBox: Box {
     /// ---
     ///
     /// [Schema definition](https://www.w3.org/TR/xmlschema-2/#decimal)
-    func xmlString() -> String? {
+    var xmlString: String? {
         return "\(unboxed)"
     }
 }

Sources/XMLCoder/Auxiliaries/Box/DoubleBox.swift

@@ -0,0 +1,48 @@
+//
+//  DoubleBox.swift
+//  XMLCoder
+//
+//  Created by Max Desiatov on 05/10/2019.
+//
+
+struct DoubleBox: Equatable, ValueBox {
+    typealias Unboxed = Double
+
+    let unboxed: Unboxed
+
+    init(_ value: Unboxed) {
+        unboxed = value
+    }
+
+    init?(xmlString: String) {
+        guard let unboxed = Double(xmlString) else { return nil }
+
+        self.init(unboxed)
+    }
+}
+
+extension DoubleBox: Box {
+    var isNull: Bool {
+        return false
+    }
+
+    var xmlString: String? {
+        guard !unboxed.isNaN else {
+            return "NaN"
+        }
+
+        guard !unboxed.isInfinite else {
+            return (unboxed > 0.0) ? "INF" : "-INF"
+        }
+
+        return unboxed.description
+    }
+}
+
+extension DoubleBox: SimpleBox {}
+
+extension DoubleBox: CustomStringConvertible {
+    var description: String {
+        return unboxed.description
+    }
+}

Sources/XMLCoder/Auxiliaries/Box/FloatBox.swift

@@ -5,8 +5,8 @@
 //  Created by Vincent Esche on 12/17/18.
 //
 
-struct FloatBox: Equatable {
-    typealias Unboxed = Float64
+struct FloatBox: Equatable, ValueBox {
+    typealias Unboxed = Float
 
     let unboxed: Unboxed
 
@@ -20,10 +20,6 @@ struct FloatBox: Equatable {
         }
         self.init(unboxed)
     }
-
-    func unbox<Float: BinaryFloatingPoint>() -> Float? {
-        return Float(exactly: unboxed)
-    }
 }
 
 extension FloatBox: Box {
@@ -59,7 +55,7 @@ extension FloatBox: Box {
     /// ---
     ///
     /// [Schema definition](https://www.w3.org/TR/xmlschema-2/#float)
-    func xmlString() -> String? {
+    var xmlString: String? {
         guard !unboxed.isNaN else {
             return "NaN"
         }

Sources/XMLCoder/Auxiliaries/Box/IntBox.swift

@@ -44,7 +44,7 @@ extension IntBox: Box {
     /// ---
     ///
     /// [Schema definition](https://www.w3.org/TR/xmlschema-2/#integer)
-    func xmlString() -> String? {
+    var xmlString: String? {
         return unboxed.description
     }
 }

Sources/XMLCoder/Auxiliaries/Box/KeyedBox.swift

@@ -43,7 +43,7 @@ extension KeyedBox: Box {
         return false
     }
 
-    func xmlString() -> String? {
+    var xmlString: String? {
         return nil
     }
 }

Sources/XMLCoder/Auxiliaries/Box/NullBox.swift

@@ -12,7 +12,7 @@ extension NullBox: Box {
         return true
     }
 
-    func xmlString() -> String? {
+    var xmlString: String? {
         return nil
     }
 }

Sources/XMLCoder/Auxiliaries/Box/SharedBox.swift

@@ -22,8 +22,8 @@ extension SharedBox: Box {
         return unboxed.isNull
     }
 
-    func xmlString() -> String? {
-        return unboxed.xmlString()
+    var xmlString: String? {
+        return unboxed.xmlString
     }
 }
 

Sources/XMLCoder/Auxiliaries/Box/SingleKeyedBox.swift

@@ -18,7 +18,7 @@ extension SingleKeyedBox: Box {
         return false
     }
 
-    func xmlString() -> String? {
+    var xmlString: String? {
         return nil
     }
 }

Sources/XMLCoder/Auxiliaries/Box/StringBox.swift

@@ -24,7 +24,7 @@ extension StringBox: Box {
         return false
     }
 
-    func xmlString() -> String? {
+    var xmlString: String? {
         return unboxed.description
     }
 }

Sources/XMLCoder/Auxiliaries/Box/UIntBox.swift

@@ -47,7 +47,7 @@ extension UIntBox: Box {
     /// ---
     ///
     /// [Schema definition](https://www.w3.org/TR/xmlschema-2/#nonNegativeInteger)
-    func xmlString() -> String? {
+    var xmlString: String? {
         return unboxed.description
     }
 }

Sources/XMLCoder/Auxiliaries/Box/URLBox.swift

@@ -29,7 +29,7 @@ extension URLBox: Box {
         return false
     }
 
-    func xmlString() -> String? {
+    var xmlString: String? {
         return unboxed.absoluteString
     }
 }

Sources/XMLCoder/Auxiliaries/Box/UnkeyedBox.swift

@@ -12,7 +12,7 @@ extension Array: Box {
         return false
     }
 
-    func xmlString() -> String? {
+    var xmlString: String? {
         return nil
     }
 }

Sources/XMLCoder/Auxiliaries/Box/ValueBox.swift

@@ -0,0 +1,12 @@
+//
+//  File.swift
+//  XMLCoder
+//
+//  Created by Max Desiatov on 05/10/2019.
+//
+
+protocol ValueBox: SimpleBox {
+    associatedtype Unboxed
+
+    init(_ value: Unboxed)
+}

Sources/XMLCoder/Auxiliaries/XMLCoderElement.swift

@@ -288,7 +288,7 @@ extension XMLCoderElement {
         }
 
         let attributes: [Attribute] = box.attributes.compactMap { key, box in
-            guard let value = box.xmlString() else {
+            guard let value = box.xmlString else {
                 return nil
             }
             return Attribute(key: key, value: value)
@@ -299,7 +299,7 @@ extension XMLCoderElement {
 
     init(key: String, box: SimpleBox) {
         self.init(key: key)
-        value = box.xmlString()
+        value = box.xmlString
     }
 
     init(key: String, box: Box) {

Sources/XMLCoder/Decoder/DecodingErrorExtension.swift

@@ -43,6 +43,8 @@ extension DecodingError {
             return "an unsigned integer value"
         case is FloatBox:
             return "a floating-point value"
+        case is DoubleBox:
+            return "a double floating-point value"
         case is UnkeyedBox:
             return "a array value"
         case is KeyedBox:

Sources/XMLCoder/Decoder/SingleValueDecodingContainer.swift

@@ -31,7 +31,11 @@ extension XMLDecoderImplementation: SingleValueDecodingContainer {
         return try unbox(try topContainer())
     }
 
-    public func decode<T: BinaryFloatingPoint & Decodable>(_: T.Type) throws -> T {
+    public func decode(_: Float.Type) throws -> Float {
+        return try unbox(try topContainer())
+    }
+
+    public func decode(_: Double.Type) throws -> Double {
         return try unbox(try topContainer())
     }
 

Sources/XMLCoder/Decoder/XMLDecoderImplementation.swift

@@ -286,22 +286,26 @@ extension XMLDecoderImplementation {
         return uint
     }
 
-    func unbox<T: BinaryFloatingPoint & Decodable>(_ box: Box) throws -> T {
-        let stringBox: StringBox = try typedBox(box, for: T.self)
+    func unbox(_ box: Box) throws -> Float {
+        let stringBox: StringBox = try typedBox(box, for: Float.self)
         let string = stringBox.unboxed
 
         guard let floatBox = FloatBox(xmlString: string) else {
-            throw DecodingError.typeMismatch(at: codingPath, expectation: T.self, reality: box)
+            throw DecodingError.typeMismatch(at: codingPath, expectation: Float.self, reality: box)
         }
 
-        guard let float: T = floatBox.unbox() else {
-            throw DecodingError.dataCorrupted(DecodingError.Context(
-                codingPath: codingPath,
-                debugDescription: "Parsed XML number <\(string)> does not fit in \(T.self)."
-            ))
+        return floatBox.unboxed
+    }
+
+    func unbox(_ box: Box) throws -> Double {
+        let stringBox: StringBox = try typedBox(box, for: Double.self)
+        let string = stringBox.unboxed
+
+        guard let doubleBox = DoubleBox(xmlString: string) else {
+            throw DecodingError.typeMismatch(at: codingPath, expectation: Double.self, reality: box)
         }
 
-        return float
+        return doubleBox.unboxed
     }
 
     func unbox(_ box: Box) throws -> String {

Sources/XMLCoder/Encoder/XMLEncoderImplementation.swift

@@ -165,13 +165,26 @@ extension XMLEncoderImplementation {
         return UIntBox(value)
     }
 
-    func box<T: BinaryFloatingPoint & Encodable>(_ value: T) throws -> SimpleBox {
+    func box(_ value: Float) throws -> SimpleBox {
+        return try box(value, FloatBox.self)
+    }
+
+    func box(_ value: Double) throws -> SimpleBox {
+        return try box(value, DoubleBox.self)
+    }
+
+    func box<T: BinaryFloatingPoint & Encodable, B: ValueBox>(
+        _ value: T,
+        _: B.Type
+    ) throws -> SimpleBox where B.Unboxed == T {
         guard value.isInfinite || value.isNaN else {
-            return FloatBox(value)
+            return B(value)
         }
-        guard case let .convertToString(positiveInfinity: posInfString,
-                                        negativeInfinity: negInfString,
-                                        nan: nanString) = options.nonConformingFloatEncodingStrategy else {
+        guard case let .convertToString(
+            positiveInfinity: posInfString,
+            negativeInfinity: negInfString,
+            nan: nanString
+        ) = options.nonConformingFloatEncodingStrategy else {
             throw EncodingError._invalidFloatingPointValue(value, at: codingPath)
         }
         if value == T.infinity {

Tests/XMLCoderTests/Box/BoolBoxTests.swift

@@ -36,7 +36,7 @@ class BoolBoxTests: XCTestCase {
 
         for (unboxed, string) in values {
             let box = Boxed(unboxed)
-            XCTAssertEqual(box.xmlString(), string)
+            XCTAssertEqual(box.xmlString, string)
         }
     }
 

Tests/XMLCoderTests/Box/DataBoxTests.swift

@@ -42,7 +42,7 @@ class DataBoxTests: XCTestCase {
 
             guard let box = boxOrNil else { continue }
 
-            XCTAssertEqual(box.xmlString(), xmlString)
+            XCTAssertEqual(box.xmlString, xmlString)
         }
     }
 

Tests/XMLCoderTests/Box/DateBoxTests.swift

@@ -48,7 +48,7 @@ class DateBoxTests: XCTestCase {
 
             guard let box = boxOrNil else { continue }
 
-            XCTAssertEqual(box.xmlString(), xmlString)
+            XCTAssertEqual(box.xmlString, xmlString)
         }
     }
 
@@ -65,7 +65,7 @@ class DateBoxTests: XCTestCase {
 
             guard let box = boxOrNil else { continue }
 
-            XCTAssertEqual(box.xmlString(), xmlString)
+            XCTAssertEqual(box.xmlString, xmlString)
         }
     }
 
@@ -80,7 +80,7 @@ class DateBoxTests: XCTestCase {
 
             guard let box = boxOrNil else { continue }
 
-            XCTAssertEqual(box.xmlString(), xmlString)
+            XCTAssertEqual(box.xmlString, xmlString)
         }
     }
 
@@ -95,7 +95,7 @@ class DateBoxTests: XCTestCase {
 
             guard let box = boxOrNil else { continue }
 
-            XCTAssertEqual(box.xmlString(), xmlString)
+            XCTAssertEqual(box.xmlString, xmlString)
         }
     }