Add Checksum protocol and simplify CRC verification

Sources/CRC+Verify.swift

@@ -9,29 +9,32 @@ import Foundation
 
 public struct VerificationError<Value: FixedWidthInteger>: Error, CustomStringConvertible {
 
+ // MARK: Stored Properties
+
  public let actualValue: Value
  public let expectedValue: Value
 
- public init(actual: Value, expected: Value) {
- self.actualValue = actual
- self.expectedValue = expected
- }
+ // MARK: Computed Properties
 
  public var description: String {
  "\(String(describing: Self.self))(expected: 0x\(expectedValue.hex), actual: 0x\(actualValue.hex))"
  }
 
+ // MARK: Initialization
+
+ internal init(actual: Value, expected: Value) {
+ self.actualValue = actual
+ self.expectedValue = expected
+ }
+
 }
 
-extension CRC {
+extension Checksum {
 
- public func verify<S: Sequence<UInt8>>(_ expectedValue: Value, for bytes: S) throws {
- let actualValue = calculate(for: bytes)
- guard expectedValue == actualValue else {
- throw VerificationError(
- actual: actualValue,
- expected: expectedValue
- )
+ public func verify<S: Sequence<UInt8>>(_ expectedValue: Value, for data: S) throws {
+ let actualValue = calculate(for: data)
+ guard actualValue == expectedValue else {
+ throw VerificationError(actual: actualValue, expected: expectedValue)
  }
  }
 
@@ -50,21 +53,3 @@ extension CRCCalculator {
  }
 
 }
-
-extension FixedWidthInteger {
-
- internal var hex: String {
- withUnsafeBytes(of: bigEndian) { $0.hex }
- }
-
-}
-
-extension Sequence<UInt8> {
-
- internal var hex: String {
- self
- .map { String(format: "%02hhX", $0) }
- .joined()
- }
-
-}

Sources/CRC.swift

@@ -6,7 +6,7 @@
 
 import Foundation
 
-public struct CRC<Value: FixedWidthInteger> {
+public struct CRC<Value: FixedWidthInteger>: Checksum {
 
  // MARK: Stored Properties
 

Sources/CRC32.swift

@@ -17,7 +17,6 @@ extension CRC32 {
  public static let posix = Self(polynomial: 0x04C11DB7, xorOut: 0xFFFFFFFF)
  public static let sata = Self(polynomial: 0x04C11DB7, initialValue: 0x52325032)
  public static let xfer = Self(polynomial: 0x000000AF)
-
  public static let c = Self(polynomial: 0x1EDC6F41, initialValue: 0xFFFFFFFF, reflected: true, xorOut: 0xFFFFFFFF)
  public static let d = Self(polynomial: 0xA833982B, initialValue: 0xFFFFFFFF, reflected: true, xorOut: 0xFFFFFFFF)
  public static let q = Self(polynomial: 0x814141AB)

Sources/Checksum.swift

@@ -0,0 +1,14 @@
+//
+// File.swift
+// 
+//
+// Created by Paul Kraft on 26.07.23.
+//
+
+import Foundation
+
+public protocol Checksum {
+ associatedtype Value: FixedWidthInteger
+
+ func calculate<S: Sequence<UInt8>>(for data: S) -> Value
+}

Sources/Hex.swift

@@ -0,0 +1,26 @@
+//
+// File.swift
+// 
+//
+// Created by Paul Kraft on 26.07.23.
+//
+
+import Foundation
+
+extension FixedWidthInteger {
+
+ internal var hex: String {
+ withUnsafeBytes(of: bigEndian) { $0.hex }
+ }
+
+}
+
+extension Sequence<UInt8> {
+
+ internal var hex: String {
+ self
+ .map { String(format: "%02hhX", $0) }
+ .joined()
+ }
+
+}