Add project files.

2025-08-09 15:45:34 -06:00
commit c547297c1e
56 changed files with 3908 additions and 0 deletions
--- a/AutomatedROMTools-CLI/CRC32CryptoServiceProvider.cs
+++ b/AutomatedROMTools-CLI/CRC32CryptoServiceProvider.cs
@@ -0,0 +1,114 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Security.Cryptography;
+
+namespace AutomatedROMTools
+{
+    /// <summary>
+    /// Implements a 32-bit CRC hash algorithm compatible with Zip etc.
+    /// </summary>
+    /// <remarks>
+    /// If you need to call multiple times for the same data either use the HashAlgorithm
+    /// interface or remember that the result of one Compute call needs to be ~ (XOR) before
+    /// being passed in as the seed for the next Compute call.
+    /// </remarks>
+    public sealed class CRC32CryptoServiceProvider : HashAlgorithm
+    {
+        public const UInt32 DefaultPolynomial = 0xedb88320u;
+        public const UInt32 DefaultSeed = 0xffffffffu;
+        static UInt32[] defaultTable;
+        readonly UInt32 seed;
+        readonly UInt32[] table;
+        UInt32 hash;
+
+        public CRC32CryptoServiceProvider() : this(DefaultPolynomial, DefaultSeed)
+        {
+
+        }
+
+        public CRC32CryptoServiceProvider(UInt32 polynomial, UInt32 seed)
+        {
+            table = InitializeTable(polynomial);
+            this.seed = hash = seed;
+        }
+
+        public override void Initialize()
+        {
+            hash = seed;
+        }
+
+        protected override void HashCore(byte[] array, int ibStart, int cbSize)
+        {
+            hash = CalculateHash(table, hash, array, ibStart, cbSize);
+        }
+
+        protected override byte[] HashFinal()
+        {
+            var hashBuffer = UInt32ToBigEndianBytes(~hash);
+            HashValue = hashBuffer;
+            return hashBuffer;
+        }
+
+        public override int HashSize
+        {
+            get { return 32; }
+        }
+
+        public static UInt32 Compute(byte[] buffer)
+        {
+            return Compute(DefaultSeed, buffer);
+        }
+
+        public static UInt32 Compute(UInt32 seed, byte[] buffer)
+        {
+            return Compute(DefaultPolynomial, seed, buffer);
+        }
+
+        public static UInt32 Compute(UInt32 polynomial, UInt32 seed, byte[] buffer)
+        {
+            return ~CalculateHash(InitializeTable(polynomial), seed, buffer, 0, buffer.Length);
+        }
+
+        static UInt32[] InitializeTable(UInt32 polynomial)
+        {
+            if (polynomial == DefaultPolynomial && defaultTable != null)
+                return defaultTable;
+
+            var createTable = new UInt32[256];
+            for (var i = 0; i < 256; i++)
+            {
+                var entry = (UInt32)i;
+                for (var j = 0; j < 8; j++)
+                    if ((entry & 1) == 1)
+                        entry = (entry >> 1) ^ polynomial;
+                    else
+                        entry = entry >> 1;
+                createTable[i] = entry;
+            }
+
+            if (polynomial == DefaultPolynomial)
+                defaultTable = createTable;
+
+            return createTable;
+        }
+
+        static UInt32 CalculateHash(UInt32[] table, UInt32 seed, IList<byte> buffer, int start, int size)
+        {
+            var hash = seed;
+            for (var i = start; i < start + size; i++)
+                hash = (hash >> 8) ^ table[buffer[i] ^ hash & 0xff];
+            return hash;
+        }
+
+        static byte[] UInt32ToBigEndianBytes(UInt32 uint32)
+        {
+            var result = BitConverter.GetBytes(uint32);
+
+            if (BitConverter.IsLittleEndian)
+                Array.Reverse(result);
+
+            return result;
+        }
+    }
+}