From 3fa44a3e9d8367fd0a2916e0312d7d58fa8189a0 Mon Sep 17 00:00:00 2001
From: Anders Bjerner <abjerner@skybrud.dk>
Date: Mon, 14 Feb 2022 16:21:00 +0100
Subject: [PATCH] Introduced new "StringUtils.ParseHexString" method

---
 .../Strings/StringUtils.Bytes.cs              | 20 ++++++
 src/UnitTestProject1/Strings/HexTests.cs      | 71 +++++++++++++++++++
 src/UnitTestProject1/UnitTestProject1.csproj  |  1 +
 3 files changed, 92 insertions(+)
 create mode 100644 src/UnitTestProject1/Strings/HexTests.cs

diff --git a/src/Skybrud.Essentials/Strings/StringUtils.Bytes.cs b/src/Skybrud.Essentials/Strings/StringUtils.Bytes.cs
index 7bcdb60..77aebb8 100644
--- a/src/Skybrud.Essentials/Strings/StringUtils.Bytes.cs
+++ b/src/Skybrud.Essentials/Strings/StringUtils.Bytes.cs
@@ -1,4 +1,5 @@
 using System;
+using System.Linq;
 
 namespace Skybrud.Essentials.Strings {
 
@@ -26,6 +27,25 @@ public static string ToHexString(byte[] bytes, HexFormat format) {
                 _ => throw new Exception($"Unsupported format: {format}")
             };
         }
+        
+        /// <summary>
+        /// Parse the specified HEX string into a corresponding array of <see cref="byte"/>.
+        /// </summary>
+        /// <param name="hex">The HEX string to parse.</param>
+        /// <returns></returns>
+        public static byte[] ParseHexString(string hex) {
+            
+            if (string.IsNullOrWhiteSpace(hex)) throw new ArgumentNullException(nameof(hex));
+            
+            // Detect whether the HEX string uses hyphens
+            int mod = hex.Length > 2 && hex[2] == '-' ? 3 : 2;
+            
+            return Enumerable.Range(0, hex.Length)
+                .Where(x => x % mod == 0)
+                .Select(x => Convert.ToByte(hex.Substring(x, 2), 16))
+                .ToArray();
+
+        }
 
     }
 
diff --git a/src/UnitTestProject1/Strings/HexTests.cs b/src/UnitTestProject1/Strings/HexTests.cs
new file mode 100644
index 0000000..d0e5a65
--- /dev/null
+++ b/src/UnitTestProject1/Strings/HexTests.cs
@@ -0,0 +1,71 @@
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using Skybrud.Essentials.Strings;
+using System.Text;
+
+namespace UnitTestProject1.Strings {
+    
+    [TestClass]
+    public class HexTests {
+
+        [TestMethod]
+        public void ToHexString() {
+            
+            byte[] bytes1 = Encoding.UTF8.GetBytes("hello world");
+            byte[] bytes2 = Encoding.UTF8.GetBytes("rød grød med fløde");
+            byte[] bytes3 = Encoding.GetEncoding(1252).GetBytes("rød grød med fløde");
+            
+            string result1 = StringUtils.ToHexString(bytes1);
+            string result2 = StringUtils.ToHexString(bytes2);
+            string result3 = StringUtils.ToHexString(bytes3);
+            
+            Assert.AreEqual("68656c6c6f20776f726c64", result1, "#1");
+            Assert.AreEqual("72c3b864206772c3b864206d656420666cc3b86465", result2, "#2");
+            Assert.AreEqual("72f864206772f864206d656420666cf86465", result3, "#3");
+
+        }
+
+        [TestMethod]
+        public void ParseHexString() {
+            
+            string hex1 = "68656c6c6f20776f726c64";
+            string hex2 = "72c3b864206772c3b864206d656420666cc3b86465";
+            string hex3 = "72f864206772f864206d656420666cf86465";
+            
+            byte[] result1 = StringUtils.ParseHexString(hex1);
+            byte[] result2 = StringUtils.ParseHexString(hex2);
+            byte[] result3 = StringUtils.ParseHexString(hex3);
+            
+            string str1 = Encoding.UTF8.GetString(result1);
+            string str2 = Encoding.UTF8.GetString(result2);
+            string str3 = Encoding.GetEncoding(1252).GetString(result3);
+            
+            Assert.AreEqual("hello world", str1, "#1");
+            Assert.AreEqual("rød grød med fløde", str2, "#2");
+            Assert.AreEqual("rød grød med fløde", str3, "#3");
+
+        }
+
+        [TestMethod]
+        public void ParseHexStringWithHypens() {
+            
+            string hex1 = "68-65-6c-6c-6f-20-77-6f-72-6c-64";
+            string hex2 = "72-c3-b8-64-20-67-72-c3-b8-64-20-6d-65-64-20-66-6c-c3-b8-64-65";
+            string hex3 = "72-f8-64-20-67-72-f8-64-20-6d-65-64-20-66-6c-f8-64-65";
+            
+            byte[] result1 = StringUtils.ParseHexString(hex1);
+            byte[] result2 = StringUtils.ParseHexString(hex2);
+            byte[] result3 = StringUtils.ParseHexString(hex3);
+            
+            string str1 = Encoding.UTF8.GetString(result1);
+            string str2 = Encoding.UTF8.GetString(result2);
+            string str3 = Encoding.GetEncoding(1252).GetString(result3);
+            
+            Assert.AreEqual("hello world", str1, "#1");
+            Assert.AreEqual("rød grød med fløde", str2, "#2");
+            Assert.AreEqual("rød grød med fløde", str3, "#3");
+
+        }
+
+    }
+
+}
\ No newline at end of file
diff --git a/src/UnitTestProject1/UnitTestProject1.csproj b/src/UnitTestProject1/UnitTestProject1.csproj
index 34fa3cb..d93a9a3 100644
--- a/src/UnitTestProject1/UnitTestProject1.csproj
+++ b/src/UnitTestProject1/UnitTestProject1.csproj
@@ -82,6 +82,7 @@
     <Compile Include="Maps\PointTests.cs" />
     <Compile Include="Reflection\ReflectionTests.cs" />
     <Compile Include="Security\SecurityTests.cs" />
+    <Compile Include="Strings\HexTests.cs" />
     <Compile Include="Strings\HtmlTests.cs" />
     <Compile Include="Strings\NameValueCollectionTests.cs" />
     <Compile Include="Strings\StringTests.cs" />