Generalize Fletcher base class for all checksums

SabreTools.Hashing/Checksum/Adler32.cs

@@ -4,13 +4,8 @@ using static SabreTools.Hashing.Checksum.Constants;
 namespace SabreTools.Hashing.Checksum
 {
     /// <see href="https://github.com/madler/zlib/blob/v1.2.11/adler32.c"/> 
-    public class Adler32
+    public class Adler32 : ChecksumBase<uint>
     {
-        /// <summary>
-        /// The current value of the hash
-        /// </summary>
-        private uint _hash;
-
         public Adler32()
         {
             Reset();
@@ -19,18 +14,13 @@ namespace SabreTools.Hashing.Checksum
         /// <summary>
         /// Reset the internal hashing state
         /// </summary>
-        public void Reset()
+        public override void Reset()
         {
             _hash = 1;
         }
 
-        /// <summary>
-        /// Hash a block of data and append it to the existing hash
-        /// </summary>
-        /// <param name="data">Byte array representing the data</param>
-        /// <param name="offset">Offset in the byte array to include</param>
-        /// <param name="length">Length of the data to hash</param>
-        public void TransformBlock(byte[] data, int offset, int length)
+        /// <inheritdoc/>
+        public override void TransformBlock(byte[] data, int offset, int length)
         {
             // Split Adler-32 into component sums
             uint sum2 = (_hash >> 16) & 0xffff;
@@ -140,10 +130,8 @@ namespace SabreTools.Hashing.Checksum
             _hash |= sum2 << 16;
         }
 
-        /// <summary>
-        /// Finalize the hash and return as a byte array
-        /// </summary>
-        public byte[] Finalize()
+        /// <inheritdoc/>
+        public override byte[] Finalize()
         {
             return BitConverter.GetBytes(_hash);
         }

SabreTools.Hashing/Checksum/ChecksumBase.cs

@@ -5,7 +5,7 @@ namespace SabreTools.Hashing.Checksum
     /// <summary>
     /// Common base class for Fletcher checksums
     /// </summary>
-    public abstract class Fletcher
+    public abstract class ChecksumBase
     {
         /// <summary>
         /// Hash a block of data and append it to the existing hash
@@ -22,9 +22,9 @@ namespace SabreTools.Hashing.Checksum
     }
 
     /// <summary>
-    /// Common base class for Fletcher checksums
+    /// Common base class for checksums
     /// </summary>
-    public abstract class Fletcher<T> : Fletcher where T : struct
+    public abstract class ChecksumBase<T> : ChecksumBase where T : struct
     {
         /// <summary>
         /// The current value of the hash
@@ -34,7 +34,7 @@ namespace SabreTools.Hashing.Checksum
         /// <summary>
         /// Reset the internal hashing state
         /// </summary>
-        public void Reset()
+        public virtual void Reset()
         {
             _hash = default;
         }

SabreTools.Hashing/Checksum/Crc.cs

@@ -3,7 +3,7 @@ using static SabreTools.Hashing.HashOperations;
 
 namespace SabreTools.Hashing.Checksum
 {
-    public class Crc
+    public class Crc : ChecksumBase<ulong>
     {
         /// <summary>
         /// Definition used to create the runner
@@ -15,11 +15,6 @@ namespace SabreTools.Hashing.Checksum
         /// </summary>
         private readonly CrcTable _table;
 
-        /// <summary>
-        /// The current value of the hash
-        /// </summary>
-        private ulong _hash;
-
         public Crc(CrcDefinition def)
         {
             // Check for a valid bit width
@@ -31,27 +26,18 @@ namespace SabreTools.Hashing.Checksum
             _hash = def.ReflectIn ? ReverseBits(def.Init, def.Width) : def.Init;
         }
 
-        /// <summary>
-        /// Reset the internal hashing state
-        /// </summary>
-        public void Reset()
+        /// <inheritdoc/>
+        public override void Reset()
         {
             _hash = Def.Init;
         }
 
-        /// <summary>
-        /// Hash a block of data and append it to the existing hash
-        /// </summary>
-        /// <param name="data">Byte array representing the data</param>
-        /// <param name="offset">Offset in the byte array to include</param>
-        /// <param name="length">Length of the data to hash</param>
-        public void TransformBlock(byte[] data, int offset, int length)
+        /// <inheritdoc/>
+        public override void TransformBlock(byte[] data, int offset, int length)
             => _table.TransformBlock(ref _hash, data, offset, length);
 
-        /// <summary>
-        /// Finalize the hash and return as a byte array
-        /// </summary>
-        public byte[] Finalize()
+        /// <inheritdoc/>
+        public override byte[] Finalize()
         {
             // Create a copy of the hash
             ulong localHash = _hash;

SabreTools.Hashing/Checksum/Fletcher16.cs

@@ -1,7 +1,7 @@
 namespace SabreTools.Hashing.Checksum
 {
     /// <see href="https://en.wikipedia.org/wiki/Fletcher%27s_checksum#Optimizations"/> 
-    public class Fletcher16 : Fletcher<ushort>
+    public class Fletcher16 : ChecksumBase<ushort>
     {
         public Fletcher16()
         {

SabreTools.Hashing/Checksum/Fletcher32.cs

@@ -4,7 +4,7 @@ namespace SabreTools.Hashing.Checksum
 {
     /// <see href="https://en.wikipedia.org/wiki/Fletcher%27s_checksum#Optimizations"/> 
     /// <remarks>Uses an Adler-32-like implementation instead of the above</remarks>
-    public class Fletcher32 : Fletcher<uint>
+    public class Fletcher32 : ChecksumBase<uint>
     {
         public Fletcher32()
         {

SabreTools.Hashing/Checksum/Fletcher64.cs

@@ -4,7 +4,7 @@ namespace SabreTools.Hashing.Checksum
 {
     /// <see href="https://en.wikipedia.org/wiki/Fletcher%27s_checksum#Optimizations"/>
     /// <remarks>Uses an Adler-32-like implementation instead of the above</remarks>
-    public class Fletcher64 : Fletcher<ulong>
+    public class Fletcher64 : ChecksumBase<ulong>
     {
         public Fletcher64()
         {

SabreTools.Hashing/HashWrapper.cs

@@ -34,20 +34,10 @@ namespace SabreTools.Hashing
             {
                 switch (_hasher)
                 {
-                    case Adler32 a32:
-                        var a32Arr = a32.Finalize();
-                        Array.Reverse(a32Arr);
-                        return a32Arr;
-
-                    case Crc cr:
-                        var crArr = cr.Finalize();
-                        Array.Reverse(crArr);
-                        return crArr;
-
-                    case Fletcher fc:
-                        var fcArr = fc.Finalize();
-                        Array.Reverse(fcArr);
-                        return fcArr;
+                    case ChecksumBase cb:
+                        var cbArr = cb.Finalize();
+                        Array.Reverse(cbArr);
+                        return cbArr;
 
                     case HashAlgorithm ha:
                         return ha.Hash;
@@ -359,16 +349,8 @@ namespace SabreTools.Hashing
         {
             switch (_hasher)
             {
-                case Adler32 a32:
-                    a32.TransformBlock(buffer, offset, size);
-                    break;
-
-                case Crc cr:
-                    cr.TransformBlock(buffer, offset, size);
-                    break;
-
-                case Fletcher fc:
-                    fc.TransformBlock(buffer, offset, size);
+                case ChecksumBase cb:
+                    cb.TransformBlock(buffer, offset, size);
                     break;
 
                 case HashAlgorithm ha: