From c65184689d41c8909999ce608ffd4dc2d1208e1a Mon Sep 17 00:00:00 2001
From: Matt Nadareski <mnadareski@outlook.com>
Date: Thu, 2 Jan 2025 15:15:53 -0500
Subject: [PATCH] FNV are non-cryptographic hashes

---
 SabreTools.Hashing/Checksum/Constants.cs      | 16 ++---
 SabreTools.Hashing/Checksum/FnvBase.cs        | 21 -------
 SabreTools.Hashing/HashWrapper.cs             |  1 +
 .../NonCryptographicHash/Constants.cs         | 15 +++++
 .../FNV0_32.cs                                |  4 +-
 .../FNV0_64.cs                                |  4 +-
 .../FNV1_32.cs                                |  4 +-
 .../FNV1_64.cs                                |  4 +-
 .../FNV1a_32.cs                               |  4 +-
 .../FNV1a_64.cs                               |  4 +-
 .../NonCryptographicHash/FnvBase.cs           | 60 +++++++++++++++++++
 11 files changed, 93 insertions(+), 44 deletions(-)
 delete mode 100644 SabreTools.Hashing/Checksum/FnvBase.cs
 create mode 100644 SabreTools.Hashing/NonCryptographicHash/Constants.cs
 rename SabreTools.Hashing/{Checksum => NonCryptographicHash}/FNV0_32.cs (79%)
 rename SabreTools.Hashing/{Checksum => NonCryptographicHash}/FNV0_64.cs (79%)
 rename SabreTools.Hashing/{Checksum => NonCryptographicHash}/FNV1_32.cs (80%)
 rename SabreTools.Hashing/{Checksum => NonCryptographicHash}/FNV1_64.cs (80%)
 rename SabreTools.Hashing/{Checksum => NonCryptographicHash}/FNV1a_32.cs (80%)
 rename SabreTools.Hashing/{Checksum => NonCryptographicHash}/FNV1a_64.cs (80%)
 create mode 100644 SabreTools.Hashing/NonCryptographicHash/FnvBase.cs

diff --git a/SabreTools.Hashing/Checksum/Constants.cs b/SabreTools.Hashing/Checksum/Constants.cs
index 82c4dcf..5de3b20 100644
--- a/SabreTools.Hashing/Checksum/Constants.cs
+++ b/SabreTools.Hashing/Checksum/Constants.cs
@@ -2,7 +2,7 @@ namespace SabreTools.Hashing.Checksum
 {
     internal static class Constants
     {
-        #region Adler-32 / Fletcher-32
+        #region Adler-32
 
         /// <summary>
         /// Largest prime smaller than 65536
@@ -14,6 +14,10 @@ namespace SabreTools.Hashing.Checksum
         /// </summary>
         public const ushort A32NMAX = 5552;
 
+        #endregion
+
+        #region Fletcher-32
+
         /// <summary>
         /// Max value for a single half of a Fletcher-32 checksum
         /// </summary>
@@ -25,15 +29,5 @@ namespace SabreTools.Hashing.Checksum
         public const uint F64BASE = 0xffffffff;
 
         #endregion
-
-        #region FNV
-
-        public const uint FNV32Basis = 0x811c9dc5;
-        public const ulong FNV64Basis = 0xcbf29ce484222325;
-
-        public const uint FNV32Prime = 0x01000193;
-        public const ulong FNV64Prime = 0x00000100000001b3;
-
-        #endregion
     }
 }
\ No newline at end of file
diff --git a/SabreTools.Hashing/Checksum/FnvBase.cs b/SabreTools.Hashing/Checksum/FnvBase.cs
deleted file mode 100644
index bad90c3..0000000
--- a/SabreTools.Hashing/Checksum/FnvBase.cs
+++ /dev/null
@@ -1,21 +0,0 @@
-namespace SabreTools.Hashing.Checksum
-{
-    public abstract class FnvBase<T> : ChecksumBase<T> where T : struct
-    {
-        /// <summary>
-        /// Initial value to use
-        /// </summary>
-        protected T _basis;
-
-        /// <summary>
-        /// Round prime to use
-        /// </summary>
-        protected T _prime;
-
-        /// <inheritdoc/>
-        public override void Initialize()
-        {
-            _hash = _basis;
-        }
-    }
-}
\ No newline at end of file
diff --git a/SabreTools.Hashing/HashWrapper.cs b/SabreTools.Hashing/HashWrapper.cs
index 63eaea5..b5e3b9f 100644
--- a/SabreTools.Hashing/HashWrapper.cs
+++ b/SabreTools.Hashing/HashWrapper.cs
@@ -9,6 +9,7 @@ using Aaru.CommonTypes.Interfaces;
 using Blake3;
 #endif
 using SabreTools.Hashing.Checksum;
+using SabreTools.Hashing.NonCryptographicHash;
 using static SabreTools.Hashing.HashOperations;
 
 namespace SabreTools.Hashing
diff --git a/SabreTools.Hashing/NonCryptographicHash/Constants.cs b/SabreTools.Hashing/NonCryptographicHash/Constants.cs
new file mode 100644
index 0000000..5a1fefc
--- /dev/null
+++ b/SabreTools.Hashing/NonCryptographicHash/Constants.cs
@@ -0,0 +1,15 @@
+namespace SabreTools.Hashing.NonCryptographicHash
+{
+    internal static class Constants
+    {
+        #region FNV
+
+        public const uint FNV32Basis = 0x811c9dc5;
+        public const ulong FNV64Basis = 0xcbf29ce484222325;
+
+        public const uint FNV32Prime = 0x01000193;
+        public const ulong FNV64Prime = 0x00000100000001b3;
+
+        #endregion
+    }
+}
\ No newline at end of file
diff --git a/SabreTools.Hashing/Checksum/FNV0_32.cs b/SabreTools.Hashing/NonCryptographicHash/FNV0_32.cs
similarity index 79%
rename from SabreTools.Hashing/Checksum/FNV0_32.cs
rename to SabreTools.Hashing/NonCryptographicHash/FNV0_32.cs
index 469d679..52de50a 100644
--- a/SabreTools.Hashing/Checksum/FNV0_32.cs
+++ b/SabreTools.Hashing/NonCryptographicHash/FNV0_32.cs
@@ -1,6 +1,6 @@
-using static SabreTools.Hashing.Checksum.Constants;
+using static SabreTools.Hashing.NonCryptographicHash.Constants;
 
-namespace SabreTools.Hashing.Checksum
+namespace SabreTools.Hashing.NonCryptographicHash
 {
     public class FNV0_32 : FnvBase<uint>
     {
diff --git a/SabreTools.Hashing/Checksum/FNV0_64.cs b/SabreTools.Hashing/NonCryptographicHash/FNV0_64.cs
similarity index 79%
rename from SabreTools.Hashing/Checksum/FNV0_64.cs
rename to SabreTools.Hashing/NonCryptographicHash/FNV0_64.cs
index b3f45fe..9fbc7d7 100644
--- a/SabreTools.Hashing/Checksum/FNV0_64.cs
+++ b/SabreTools.Hashing/NonCryptographicHash/FNV0_64.cs
@@ -1,6 +1,6 @@
-using static SabreTools.Hashing.Checksum.Constants;
+using static SabreTools.Hashing.NonCryptographicHash.Constants;
 
-namespace SabreTools.Hashing.Checksum
+namespace SabreTools.Hashing.NonCryptographicHash
 {
     public class FNV0_64 : FnvBase<ulong>
     {
diff --git a/SabreTools.Hashing/Checksum/FNV1_32.cs b/SabreTools.Hashing/NonCryptographicHash/FNV1_32.cs
similarity index 80%
rename from SabreTools.Hashing/Checksum/FNV1_32.cs
rename to SabreTools.Hashing/NonCryptographicHash/FNV1_32.cs
index 267733c..86a35a6 100644
--- a/SabreTools.Hashing/Checksum/FNV1_32.cs
+++ b/SabreTools.Hashing/NonCryptographicHash/FNV1_32.cs
@@ -1,6 +1,6 @@
-using static SabreTools.Hashing.Checksum.Constants;
+using static SabreTools.Hashing.NonCryptographicHash.Constants;
 
-namespace SabreTools.Hashing.Checksum
+namespace SabreTools.Hashing.NonCryptographicHash
 {
     public class FNV1_32 : FnvBase<uint>
     {
diff --git a/SabreTools.Hashing/Checksum/FNV1_64.cs b/SabreTools.Hashing/NonCryptographicHash/FNV1_64.cs
similarity index 80%
rename from SabreTools.Hashing/Checksum/FNV1_64.cs
rename to SabreTools.Hashing/NonCryptographicHash/FNV1_64.cs
index 8a29e5a..5f22bc6 100644
--- a/SabreTools.Hashing/Checksum/FNV1_64.cs
+++ b/SabreTools.Hashing/NonCryptographicHash/FNV1_64.cs
@@ -1,6 +1,6 @@
-using static SabreTools.Hashing.Checksum.Constants;
+using static SabreTools.Hashing.NonCryptographicHash.Constants;
 
-namespace SabreTools.Hashing.Checksum
+namespace SabreTools.Hashing.NonCryptographicHash
 {
     public class FNV1_64 : FnvBase<ulong>
     {
diff --git a/SabreTools.Hashing/Checksum/FNV1a_32.cs b/SabreTools.Hashing/NonCryptographicHash/FNV1a_32.cs
similarity index 80%
rename from SabreTools.Hashing/Checksum/FNV1a_32.cs
rename to SabreTools.Hashing/NonCryptographicHash/FNV1a_32.cs
index 57a6596..c7b6c75 100644
--- a/SabreTools.Hashing/Checksum/FNV1a_32.cs
+++ b/SabreTools.Hashing/NonCryptographicHash/FNV1a_32.cs
@@ -1,6 +1,6 @@
-using static SabreTools.Hashing.Checksum.Constants;
+using static SabreTools.Hashing.NonCryptographicHash.Constants;
 
-namespace SabreTools.Hashing.Checksum
+namespace SabreTools.Hashing.NonCryptographicHash
 {
     public class FNV1a_32 : FnvBase<uint>
     {
diff --git a/SabreTools.Hashing/Checksum/FNV1a_64.cs b/SabreTools.Hashing/NonCryptographicHash/FNV1a_64.cs
similarity index 80%
rename from SabreTools.Hashing/Checksum/FNV1a_64.cs
rename to SabreTools.Hashing/NonCryptographicHash/FNV1a_64.cs
index 1dfde00..2cf5965 100644
--- a/SabreTools.Hashing/Checksum/FNV1a_64.cs
+++ b/SabreTools.Hashing/NonCryptographicHash/FNV1a_64.cs
@@ -1,6 +1,6 @@
-using static SabreTools.Hashing.Checksum.Constants;
+using static SabreTools.Hashing.NonCryptographicHash.Constants;
 
-namespace SabreTools.Hashing.Checksum
+namespace SabreTools.Hashing.NonCryptographicHash
 {
     public class FNV1a_64 : FnvBase<ulong>
     {
diff --git a/SabreTools.Hashing/NonCryptographicHash/FnvBase.cs b/SabreTools.Hashing/NonCryptographicHash/FnvBase.cs
new file mode 100644
index 0000000..f774381
--- /dev/null
+++ b/SabreTools.Hashing/NonCryptographicHash/FnvBase.cs
@@ -0,0 +1,60 @@
+using System;
+
+namespace SabreTools.Hashing.NonCryptographicHash
+{
+    /// <summary>
+    /// Common base class for FNV non-cryptographic hashes
+    /// </summary>
+    public abstract class FnvBase : System.Security.Cryptography.HashAlgorithm
+    {
+        // No common, untyped functionality
+    }
+
+    /// <summary>
+    /// Common base class for FNV non-cryptographic hashes
+    /// </summary>
+    public abstract class FnvBase<T> : FnvBase where T : struct
+    {
+        /// <summary>
+        /// Initial value to use
+        /// </summary>
+        protected T _basis;
+
+        /// <summary>
+        /// Round prime to use
+        /// </summary>
+        protected T _prime;
+
+        /// <summary>
+        /// The current value of the hash
+        /// </summary>
+        protected T _hash;
+
+        /// <inheritdoc/>
+        public override void Initialize()
+        {
+            _hash = _basis;
+        }
+
+        /// <inheritdoc/>
+        protected override byte[] HashFinal()
+        {
+            byte[] hashArr = _hash switch
+            {
+                short s => BitConverter.GetBytes(s),
+                ushort s => BitConverter.GetBytes(s),
+
+                int i => BitConverter.GetBytes(i),
+                uint i => BitConverter.GetBytes(i),
+
+                long l => BitConverter.GetBytes(l),
+                ulong l => BitConverter.GetBytes(l),
+
+                _ => [],
+            };
+
+            Array.Reverse(hashArr);
+            return hashArr;
+        }
+    }
+}
\ No newline at end of file