Add DataUnit entity

Sources/TunnelKitCore/DataUnit.swift

@@ -0,0 +1,102 @@
+//
+//  DataUnit.swift
+//  TunnelKit
+//
+//  Created by Davide De Rosa on 3/30/18.
+//  Copyright (c) 2022 Davide De Rosa. All rights reserved.
+//
+//  https://github.com/passepartoutvpn
+//
+//  This file is part of TunnelKit.
+//
+//  TunnelKit is free software: you can redistribute it and/or modify
+//  it under the terms of the GNU General Public License as published by
+//  the Free Software Foundation, either version 3 of the License, or
+//  (at your option) any later version.
+//
+//  TunnelKit is distributed in the hope that it will be useful,
+//  but WITHOUT ANY WARRANTY; without even the implied warranty of
+//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+//  GNU General Public License for more details.
+//
+//  You should have received a copy of the GNU General Public License
+//  along with TunnelKit.  If not, see <http://www.gnu.org/licenses/>.
+//
+
+import Foundation
+
+/// :nodoc:
+public enum DataUnit: UInt, CustomStringConvertible {
+    case byte = 1
+    
+    case kilobyte = 1024
+    
+    case megabyte = 1048576
+    
+    case gigabyte = 1073741824
+
+    fileprivate var showsDecimals: Bool {
+        switch self {
+        case .byte, .kilobyte:
+            return false
+            
+        case .megabyte, .gigabyte:
+            return true
+        }
+    }
+    
+    fileprivate var boundary: UInt {
+        return UInt(0.1 * Double(rawValue))
+    }
+    
+    // MARK: CustomStringConvertible
+    
+    public var description: String {
+        switch self {
+        case .byte:
+            return "B"
+
+        case .kilobyte:
+            return "kB"
+
+        case .megabyte:
+            return "MB"
+
+        case .gigabyte:
+            return "GB"
+        }
+    }
+}
+
+/// :nodoc:
+extension UInt {
+    private static let allUnits: [DataUnit] = [
+        .gigabyte,
+        .megabyte,
+        .kilobyte,
+        .byte
+    ]
+    
+    public var descriptionAsDataUnit: String {
+        if self == 0 {
+            return "0B"
+        }
+        for u in Self.allUnits {
+            if self >= u.boundary {
+                if !u.showsDecimals {
+                    return "\(self / u.rawValue)\(u)"
+                }
+                let count = Double(self) / Double(u.rawValue)
+                return String(format: "%.2f%@", count, u.description)
+            }
+        }
+        fatalError("Number is negative")
+    }
+}
+
+/// :nodoc:
+extension Int {
+    public var descriptionAsDataUnit: String {
+        return UInt(self).descriptionAsDataUnit
+    }
+}

Tests/TunnelKitCoreTests/DataManipulationTests.swift

@@ -82,4 +82,19 @@ class DataManipulationTests: XCTestCase {
         v.append(Data(hex: "112233"))
         XCTAssertEqual(v.flatCount, 21)
     }
+
+    func testDataUnitDescription() {
+        XCTAssertEqual(0.descriptionAsDataUnit, "0B")
+        XCTAssertEqual(1.descriptionAsDataUnit, "1B")
+        XCTAssertEqual(1024.descriptionAsDataUnit, "1kB")
+        XCTAssertEqual(1025.descriptionAsDataUnit, "1kB")
+        XCTAssertEqual(548575.descriptionAsDataUnit, "0.52MB")
+        XCTAssertEqual(1048575.descriptionAsDataUnit, "1.00MB")
+        XCTAssertEqual(1048576.descriptionAsDataUnit, "1.00MB")
+        XCTAssertEqual(1048577.descriptionAsDataUnit, "1.00MB")
+        XCTAssertEqual(600000000.descriptionAsDataUnit, "0.56GB")
+        XCTAssertEqual(1073741823.descriptionAsDataUnit, "1.00GB")
+        XCTAssertEqual(1073741824.descriptionAsDataUnit, "1.00GB")
+        XCTAssertEqual(1073741825.descriptionAsDataUnit, "1.00GB")
+    }
 }