Merge pull request #1915 from Bond-009/hex

Rewrite hex encoder/decoder

6 files changed, 126 insertions, 79 deletions

diff --git a/MediaBrowser.Common/Cryptography/PasswordHash.cs b/MediaBrowser.Common/Cryptography/PasswordHash.cs
index dca31cd92..4c6804097 100644
--- a/MediaBrowser.Common/Cryptography/PasswordHash.cs
+++ b/MediaBrowser.Common/Cryptography/PasswordHash.cs
@@ -4,7 +4,6 @@ using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Text;
-using static MediaBrowser.Common.HexHelper;
 
 namespace MediaBrowser.Common.Cryptography
 {
@@ -102,13 +101,13 @@ namespace MediaBrowser.Common.Cryptography
             // Check if the string also contains a salt
             if (splitted.Length - index == 2)
             {
-                salt = FromHexString(splitted[index++]);
-                hash = FromHexString(splitted[index++]);
+                salt = Hex.Decode(splitted[index++]);
+                hash = Hex.Decode(splitted[index++]);
             }
             else
             {
                 salt = Array.Empty<byte>();
-                hash = FromHexString(splitted[index++]);
+                hash = Hex.Decode(splitted[index++]);
             }
 
             return new PasswordHash(id, hash, salt, parameters);
@@ -145,11 +144,11 @@ namespace MediaBrowser.Common.Cryptography
             if (Salt.Length != 0)
             {
                 str.Append('$')
-                    .Append(ToHexString(Salt));
+                    .Append(Hex.Encode(Salt, false));
             }
 
             return str.Append('$')
-                .Append(ToHexString(Hash)).ToString();
+                .Append(Hex.Encode(Hash, false)).ToString();
         }
     }
 }
diff --git a/MediaBrowser.Common/Extensions/CollectionExtensions.cs b/MediaBrowser.Common/Extensions/CollectionExtensions.cs
deleted file mode 100644
index 215224398..000000000
--- a/MediaBrowser.Common/Extensions/CollectionExtensions.cs
+++ /dev/null
@@ -1,48 +0,0 @@
-#pragma warning disable CS1591
-
-using System.Collections.Generic;
-
-namespace MediaBrowser.Common.Extensions
-{
-    // The MS CollectionExtensions are only available in netcoreapp
-    public static class CollectionExtensions
-    {
-        public static TValue GetValueOrDefault<TKey, TValue>(this IReadOnlyDictionary<TKey, TValue> dictionary, TKey key)
-        {
-            dictionary.TryGetValue(key, out var ret);
-            return ret;
-        }
-
-        /// <summary>
-        /// Copies all the elements of the current collection to the specified list
-        /// starting at the specified destination array index. The index is specified as a 32-bit integer.
-        /// </summary>
-        /// <param name="source">The current collection that is the source of the elements.</param>
-        /// <param name="destination">The list that is the destination of the elements copied from the current collection.</param>
-        /// <param name="index">A 32-bit integer that represents the index in <c>destination</c> at which copying begins.</param>
-        /// <typeparam name="T"></typeparam>
-        public static void CopyTo<T>(this IReadOnlyList<T> source, IList<T> destination, int index = 0)
-        {
-            for (int i = 0; i < source.Count; i++)
-            {
-                destination[index + i] = source[i];
-            }
-        }
-
-        /// <summary>
-        /// Copies all the elements of the current collection to the specified list
-        /// starting at the specified destination array index. The index is specified as a 32-bit integer.
-        /// </summary>
-        /// <param name="source">The current collection that is the source of the elements.</param>
-        /// <param name="destination">The list that is the destination of the elements copied from the current collection.</param>
-        /// <param name="index">A 32-bit integer that represents the index in <c>destination</c> at which copying begins.</param>
-        /// <typeparam name="T"></typeparam>
-        public static void CopyTo<T>(this IReadOnlyCollection<T> source, IList<T> destination, int index = 0)
-        {
-            foreach (T item in source)
-            {
-                destination[index++] = item;
-            }
-        }
-    }
-}
diff --git a/MediaBrowser.Common/Extensions/CopyToExtensions.cs b/MediaBrowser.Common/Extensions/CopyToExtensions.cs
new file mode 100644
index 000000000..78a73f07e
--- /dev/null
+++ b/MediaBrowser.Common/Extensions/CopyToExtensions.cs
@@ -0,0 +1,26 @@
+using System.Collections.Generic;
+
+namespace MediaBrowser.Common.Extensions
+{
+    /// <summary>
+    /// Provides <c>CopyTo</c> extensions methods for <see cref="IReadOnlyList{T}" />.
+    /// </summary>
+    public static class CollectionExtensions
+    {
+        /// <summary>
+        /// Copies all the elements of the current collection to the specified list
+        /// starting at the specified destination array index. The index is specified as a 32-bit integer.
+        /// </summary>
+        /// <param name="source">The current collection that is the source of the elements.</param>
+        /// <param name="destination">The list that is the destination of the elements copied from the current collection.</param>
+        /// <param name="index">A 32-bit integer that represents the index in <c>destination</c> at which copying begins.</param>
+        /// <typeparam name="T"></typeparam>
+        public static void CopyTo<T>(this IReadOnlyList<T> source, IList<T> destination, int index = 0)
+        {
+            for (int i = 0; i < source.Count; i++)
+            {
+                destination[index + i] = source[i];
+            }
+        }
+    }
+}
diff --git a/MediaBrowser.Common/Hex.cs b/MediaBrowser.Common/Hex.cs
new file mode 100644
index 000000000..b2d9aea3a
--- /dev/null
+++ b/MediaBrowser.Common/Hex.cs
@@ -0,0 +1,94 @@
+using System;
+using System.Diagnostics.CodeAnalysis;
+
+namespace MediaBrowser.Common
+{
+    /// <summary>
+    /// Encoding and decoding hex strings.
+    /// </summary>
+    public static class Hex
+    {
+        internal const string HexCharsLower = "0123456789abcdef";
+        internal const string HexCharsUpper = "0123456789ABCDEF";
+
+        internal const int LastHexSymbol = 0x66; // 102: f
+
+        /// <summary>
+        /// Map from an ASCII char to its hex value shifted,
+        /// e.g. <c>b</c> -> 11. 0xFF means it's not a hex symbol.
+        /// </summary>
+        /// <value></value>
+        internal static ReadOnlySpan<byte> HexLookup => new byte[] {
+            0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+            0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+            0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+            0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+            0xFF, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+            0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+            0xFF, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f
+        };
+
+        /// <summary>
+        /// Encodes <c>bytes</c> as a hex string.
+        /// </summary>
+        /// <param name="bytes"></param>
+        /// <param name="lowercase"></param>
+        /// <returns><c>bytes</c> as a hex string.</returns>
+        public static string Encode(ReadOnlySpan<byte> bytes, bool lowercase = true)
+        {
+            var hexChars = lowercase ? HexCharsLower : HexCharsUpper;
+
+            // TODO: use string.Create when it's supports spans
+            // Ref: https://github.com/dotnet/corefx/issues/29120
+            char[] s = new char[bytes.Length * 2];
+            int j = 0;
+            for (int i = 0; i < bytes.Length; i++)
+            {
+                s[j++] = hexChars[bytes[i] >> 4];
+                s[j++] = hexChars[bytes[i] & 0x0f];
+            }
+
+            return new string(s);
+        }
+
+        /// <summary>
+        /// Decodes a hex string into bytes.
+        /// </summary>
+        /// <param name="str">The <see cref="string" />.</param>
+        /// <returns>The decoded bytes.</returns>
+        public static byte[] Decode(ReadOnlySpan<char> str)
+        {
+            if (str.Length == 0)
+            {
+                return Array.Empty<byte>();
+            }
+
+            var unHex = HexLookup;
+
+            int byteLen = str.Length / 2;
+            byte[] bytes = new byte[byteLen];
+            int i = 0;
+            for (int j = 0; j < byteLen; j++)
+            {
+                byte a;
+                byte b;
+                if (str[i] > LastHexSymbol
+                    || (a = unHex[str[i++]]) == 0xFF
+                    || str[i] > LastHexSymbol
+                    || (b = unHex[str[i++]]) == 0xFF)
+                {
+                    ThrowArgumentException(nameof(str));
+                    break; // Unreachable
+                }
+
+                bytes[j] = (byte)((a * 16) | b);
+            }
+
+            return bytes;
+        }
+
+        [DoesNotReturn]
+        private static void ThrowArgumentException(string paramName)
+            => throw new ArgumentException("Character is not a hex symbol.", paramName);
+    }
+}
diff --git a/MediaBrowser.Common/HexHelper.cs b/MediaBrowser.Common/HexHelper.cs
deleted file mode 100644
index 61007b5b2..000000000
--- a/MediaBrowser.Common/HexHelper.cs
+++ /dev/null
@@ -1,24 +0,0 @@
-#pragma warning disable CS1591
-
-using System;
-using System.Globalization;
-
-namespace MediaBrowser.Common
-{
-    public static class HexHelper
-    {
-        public static byte[] FromHexString(string str)
-        {
-            byte[] bytes = new byte[str.Length / 2];
-            for (int i = 0; i < str.Length; i += 2)
-            {
-                bytes[i / 2] = byte.Parse(str.Substring(i, 2), NumberStyles.HexNumber, CultureInfo.InvariantCulture);
-            }
-
-            return bytes;
-        }
-
-        public static string ToHexString(byte[] bytes)
-            => BitConverter.ToString(bytes).Replace("-", "");
-    }
-}
diff --git a/MediaBrowser.Common/MediaBrowser.Common.csproj b/MediaBrowser.Common/MediaBrowser.Common.csproj
index ec98400c8..889fbfa5a 100644
--- a/MediaBrowser.Common/MediaBrowser.Common.csproj
+++ b/MediaBrowser.Common/MediaBrowser.Common.csproj
@@ -21,7 +21,7 @@
   </ItemGroup>
 
   <PropertyGroup>
-    <TargetFramework>netstandard2.0</TargetFramework>
+    <TargetFramework>netstandard2.1</TargetFramework>
     <GenerateAssemblyInfo>false</GenerateAssemblyInfo>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>