Data commit

Task/Vigen-re-cipher/Swift/vigen-re-cipher.swift

@@ -0,0 +1,125 @@
+public func convertToUnicodeScalars(
+  str: String,
+  minChar: UInt32,
+  maxChar: UInt32
+) -> [UInt32] {
+  var scalars = [UInt32]()
+
+  for scalar in str.unicodeScalars {
+    let val = scalar.value
+
+    guard val >= minChar && val <= maxChar else {
+      continue
+    }
+
+    scalars.append(val)
+  }
+
+  return scalars
+}
+
+public struct Vigenere {
+  private let keyScalars: [UInt32]
+  private let smallestScalar: UInt32
+  private let largestScalar: UInt32
+  private let sizeAlphabet: UInt32
+
+  public init?(key: String, smallestCharacter: Character = "A", largestCharacter:  Character = "Z") {
+    let smallScalars = smallestCharacter.unicodeScalars
+    let largeScalars = largestCharacter.unicodeScalars
+
+    guard smallScalars.count == 1, largeScalars.count == 1 else {
+      return nil
+    }
+
+    self.smallestScalar = smallScalars.first!.value
+    self.largestScalar = largeScalars.first!.value
+    self.sizeAlphabet = (largestScalar - smallestScalar) + 1
+
+    let scalars = convertToUnicodeScalars(str: key, minChar: smallestScalar, maxChar: largestScalar)
+
+    guard !scalars.isEmpty else {
+      return nil
+    }
+
+    self.keyScalars = scalars
+
+  }
+
+  public func decrypt(_ str: String) -> String? {
+    let txtBytes = convertToUnicodeScalars(str: str, minChar: smallestScalar, maxChar: largestScalar)
+
+    guard !txtBytes.isEmpty else {
+      return nil
+    }
+
+    var res = ""
+
+    for (i, c) in txtBytes.enumerated() where c >= smallestScalar && c <= largestScalar {
+      guard let char =
+        UnicodeScalar((c &+ sizeAlphabet &- keyScalars[i % keyScalars.count]) % sizeAlphabet &+ smallestScalar)
+      else {
+        return nil
+      }
+
+      res += String(char)
+    }
+
+    return res
+  }
+
+  public func encrypt(_ str: String) -> String? {
+    let txtBytes = convertToUnicodeScalars(str: str, minChar: smallestScalar, maxChar: largestScalar)
+
+    guard !txtBytes.isEmpty else {
+      return nil
+    }
+
+    var res = ""
+
+    for (i, c) in txtBytes.enumerated() where c >= smallestScalar && c <= largestScalar {
+      guard let char =
+        UnicodeScalar((c &+ keyScalars[i % keyScalars.count] &- 2 &* smallestScalar) % sizeAlphabet &+ smallestScalar)
+      else {
+        return nil
+      }
+
+      res += String(char)
+    }
+
+    return res
+  }
+}
+
+let text = "Beware the Jabberwock, my son! The jaws that bite, the claws that catch!";
+let key = "VIGENERECIPHER";
+let cipher = Vigenere(key: key)!
+
+print("Key: \(key)")
+print("Plain Text: \(text)")
+
+let encoded = cipher.encrypt(text.uppercased())!
+
+print("Cipher Text: \(encoded)")
+
+let decoded = cipher.decrypt(encoded)!
+
+print("Decoded: \(decoded)")
+
+print("\nLarger set:")
+
+let key2 = "Vigenère cipher"
+let text2 = "This is a ünicode string 😃"
+
+let cipher2 = Vigenere(key: key2, smallestCharacter: " ", largestCharacter: "🛹")!
+
+print("Key: \(key2)")
+print("Plain Text: \(text2)")
+
+let encoded2 = cipher2.encrypt(text2)!
+
+print("Cipher Text: \(encoded2)")
+
+let decoded2 = cipher2.decrypt(encoded2)!
+
+print("Decoded: \(decoded2)")