From 558adfa325b0c4460e85c59823fbd55961d240e9 Mon Sep 17 00:00:00 2001
From: Morilli <35152647+Morilli@users.noreply.github.com>
Date: Sun, 12 Dec 2021 17:51:54 +0100
Subject: [PATCH] Get rid of unnecessary CRC32Checksum.cs

haven't checked for correctness or regressions
---
 src/BizHawk.Common/checksums/CRC32Checksum.cs | 33 -------------------
 src/BizHawk.Common/checksums/MD5Checksum.cs   |  1 -
 src/BizHawk.Common/checksums/SHA1Checksum.cs  |  1 -
 .../checksums/SHA256Checksum.cs               |  1 -
 .../Database/Database.cs                      |  2 +-
 .../DiscHasher.cs                             |  4 +--
 6 files changed, 3 insertions(+), 39 deletions(-)
 delete mode 100644 src/BizHawk.Common/checksums/CRC32Checksum.cs

diff --git a/src/BizHawk.Common/checksums/CRC32Checksum.cs b/src/BizHawk.Common/checksums/CRC32Checksum.cs
deleted file mode 100644
index a988b4b803..0000000000
--- a/src/BizHawk.Common/checksums/CRC32Checksum.cs
+++ /dev/null
@@ -1,33 +0,0 @@
-using System;
-
-using BizHawk.Common.BufferExtensions;
-
-namespace BizHawk.Common
-{
-	/// <summary>uses <see cref="CRC32">custom implementation</see> of CRC-32 (i.e. POSIX cksum)</summary>
-	/// <seealso cref="MD5Checksum"/>
-	/// <seealso cref="SHA1Checksum"/>
-	/// <seealso cref="SHA256Checksum"/>
-	public static class CRC32Checksum
-	{
-		/// <remarks>in bits</remarks>
-		internal const int EXPECTED_LENGTH = 32;
-
-		internal const string PREFIX = "CRC32";
-
-		public static byte[] BytesAsDigest(uint digest)
-		{
-			var a = BitConverter.GetBytes(digest);
-			return new[] { a[3], a[2], a[1], a[0] };
-		}
-
-		public static byte[] Compute(ReadOnlySpan<byte> data)
-			=> BytesAsDigest(CRC32.Calculate(data));
-
-		public static string ComputeDigestHex(ReadOnlySpan<byte> data)
-			=> Compute(data).BytesToHexString();
-
-		public static string ComputePrefixedHex(ReadOnlySpan<byte> data)
-			=> $"{PREFIX}:{ComputeDigestHex(data)}";
-	}
-}
diff --git a/src/BizHawk.Common/checksums/MD5Checksum.cs b/src/BizHawk.Common/checksums/MD5Checksum.cs
index 5ccfcf817e..bff4627401 100644
--- a/src/BizHawk.Common/checksums/MD5Checksum.cs
+++ b/src/BizHawk.Common/checksums/MD5Checksum.cs
@@ -7,7 +7,6 @@ using BizHawk.Common.BufferExtensions;
 namespace BizHawk.Common
 {
 	/// <summary>uses <see cref="MD5"/> implementation from BCL</summary>
-	/// <seealso cref="CRC32Checksum"/>
 	/// <seealso cref="SHA1Checksum"/>
 	/// <seealso cref="SHA256Checksum"/>
 	public static class MD5Checksum
diff --git a/src/BizHawk.Common/checksums/SHA1Checksum.cs b/src/BizHawk.Common/checksums/SHA1Checksum.cs
index 671dbf00c4..b9bb59a428 100644
--- a/src/BizHawk.Common/checksums/SHA1Checksum.cs
+++ b/src/BizHawk.Common/checksums/SHA1Checksum.cs
@@ -7,7 +7,6 @@ using BizHawk.Common.BufferExtensions;
 namespace BizHawk.Common
 {
 	/// <summary>uses <see cref="SHA1"/> implementation from BCL</summary>
-	/// <seealso cref="CRC32Checksum"/>
 	/// <seealso cref="MD5Checksum"/>
 	/// <seealso cref="SHA256Checksum"/>
 	public static class SHA1Checksum
diff --git a/src/BizHawk.Common/checksums/SHA256Checksum.cs b/src/BizHawk.Common/checksums/SHA256Checksum.cs
index 63199db60d..ab0fb2904c 100644
--- a/src/BizHawk.Common/checksums/SHA256Checksum.cs
+++ b/src/BizHawk.Common/checksums/SHA256Checksum.cs
@@ -7,7 +7,6 @@ using BizHawk.Common.BufferExtensions;
 namespace BizHawk.Common
 {
 	/// <summary>uses <see cref="SHA256"/> implementation from BCL</summary>
-	/// <seealso cref="CRC32Checksum"/>
 	/// <seealso cref="MD5Checksum"/>
 	/// <seealso cref="SHA1Checksum"/>
 	public static class SHA256Checksum
diff --git a/src/BizHawk.Emulation.Common/Database/Database.cs b/src/BizHawk.Emulation.Common/Database/Database.cs
index 229d337bc7..b8106f81e8 100644
--- a/src/BizHawk.Emulation.Common/Database/Database.cs
+++ b/src/BizHawk.Emulation.Common/Database/Database.cs
@@ -190,7 +190,7 @@ namespace BizHawk.Emulation.Common
 		{
 			acquire.WaitOne();
 
-			var hashCRC32 = CRC32Checksum.ComputeDigestHex(romData);
+			var hashCRC32 = CRC32.Calculate(romData).ToString("X8");
 			if (DB.TryGetValue(hashCRC32, out var cgi))
 			{
 				return new GameInfo(cgi);
diff --git a/src/BizHawk.Emulation.DiscSystem/DiscHasher.cs b/src/BizHawk.Emulation.DiscSystem/DiscHasher.cs
index b0657d252f..39bceb3621 100644
--- a/src/BizHawk.Emulation.DiscSystem/DiscHasher.cs
+++ b/src/BizHawk.Emulation.DiscSystem/DiscHasher.cs
@@ -54,7 +54,7 @@ namespace BizHawk.Emulation.DiscSystem
 				crc.Add(buffer2352);
 			}
 
-			return CRC32Checksum.BytesAsDigest(crc.Result).BytesToHexString();
+			return crc.Result.ToString("X8");
 		}
 
 		/// <summary>
@@ -102,4 +102,4 @@ namespace BizHawk.Emulation.DiscSystem
 			return "no data track found";
 		}
 	}
-}
\ No newline at end of file
+}