feat: add data from hex

Sources/BasedUtils/extensions/Data.swift

@@ -9,6 +9,32 @@ import Foundation
 
 public extension Data {
 
+    /// Returns Data from given hex string.
+    ///  - an empty string will return `nil`;
+    ///  - an empty hex string is equal to `"0x"` and will return empty `Data` object.
+    /// - Parameter hex: bytes represented as string.
+    /// - Returns: optional raw bytes.
+    static func fromHex(_ hex: String) -> Data? {
+        let hex = hex.lowercased().trimmingCharacters(in: .whitespacesAndNewlines)
+        guard !hex.isEmpty else { return nil }
+        guard hex != "0x" else { return Data() }
+        let rawHex = hex.removeHexPrefix()
+        guard rawHex.count % 2 == 0 else { return nil }
+        var data = Data(capacity: rawHex.count / 2)
+        var index = rawHex.startIndex
+        while index < rawHex.endIndex {
+            let nextIndex = rawHex.index(index, offsetBy: 2)
+            let byteString = rawHex[index..<nextIndex]
+            if let byte = UInt8(byteString, radix: 16) {
+                data.append(byte)
+            } else {
+                return nil
+            }
+            index = nextIndex
+        }
+        return data
+    }
+
     func base64UrlEncode() -> String {
         var base64String = self.base64EncodedString()
         // Replace standard Base64 characters to make it URL-safe
@@ -20,4 +46,3 @@ public extension Data {
     }
 
 }
-

Tests/BasedUtilsTests/DataExtensionsTests.swift

@@ -23,4 +23,11 @@ final class DataExtensionsTests: XCTestCase {
         XCTAssertEqual(emptyString.base64UrlEncode(), "")
     }
 
+    func testFromHex() throws {
+        XCTAssertEqual(Data.fromHex("0x"), Data())
+        XCTAssertEqual(Data.fromHex("0x61"), Data([97]))
+        XCTAssertEqual(Data.fromHex("0x48656c6c6f20576f726c6421"), Data([72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33]))
+        XCTAssertEqual(Data.fromHex("0x420fggf11a"), nil)
+    }
+
 }