From 36c7a0d9a777f0fccffec90aa53a5ba7c648b7de Mon Sep 17 00:00:00 2001
From: Peter Dettman <peter.dettman@bouncycastle.org>
Date: Wed, 9 Nov 2022 18:37:51 +0700
Subject: Crc24 perf. opts.

---
 crypto/src/bcpg/ArmoredInputStream.cs | 18 +++++++++---------
 crypto/src/bcpg/Crc24.cs              | 25 ++++++++++---------------
 2 files changed, 19 insertions(+), 24 deletions(-)

diff --git a/crypto/src/bcpg/ArmoredInputStream.cs b/crypto/src/bcpg/ArmoredInputStream.cs
index ab9a303dd..7bd7b5c04 100644
--- a/crypto/src/bcpg/ArmoredInputStream.cs
+++ b/crypto/src/bcpg/ArmoredInputStream.cs
@@ -53,7 +53,7 @@ namespace Org.BouncyCastle.Bcpg
         *
         * @return the offset the data starts in out.
         */
-        private static int Decode(int in0, int in1, int in2, int in3, int[] result)
+        private static int Decode(int in0, int in1, int in2, int in3, byte[] result)
         {
             if (in3 < 0)
                 throw new EndOfStreamException("unexpected end of file in armored stream.");
@@ -66,7 +66,7 @@ namespace Org.BouncyCastle.Bcpg
                 if ((b1 | b2) >= 128)
                     throw new IOException("invalid armor");
 
-                result[2] = ((b1 << 2) | (b2 >> 4)) & 0xff;
+                result[2] = (byte)((b1 << 2) | (b2 >> 4));
                 return 2;
             }
             else if (in3 == '=')
@@ -77,8 +77,8 @@ namespace Org.BouncyCastle.Bcpg
                 if ((b1 | b2 | b3) >= 128)
                     throw new IOException("invalid armor");
 
-                result[1] = ((b1 << 2) | (b2 >> 4)) & 0xff;
-                result[2] = ((b2 << 4) | (b3 >> 2)) & 0xff;
+                result[1] = (byte)((b1 << 2) | (b2 >> 4));
+                result[2] = (byte)((b2 << 4) | (b3 >> 2));
                 return 1;
             }
             else
@@ -90,9 +90,9 @@ namespace Org.BouncyCastle.Bcpg
                 if ((b1 | b2 | b3 | b4) >= 128)
                     throw new IOException("invalid armor");
 
-                result[0] = ((b1 << 2) | (b2 >> 4)) & 0xff;
-                result[1] = ((b2 << 4) | (b3 >> 2)) & 0xff;
-                result[2] = ((b3 << 6) | b4) & 0xff;
+                result[0] = (byte)((b1 << 2) | (b2 >> 4));
+                result[1] = (byte)((b2 << 4) | (b3 >> 2));
+                result[2] = (byte)((b3 << 6) | b4);
                 return 0;
             }
         }
@@ -105,7 +105,7 @@ namespace Org.BouncyCastle.Bcpg
 
         Stream      input;
         bool        start = true;
-        int[]       outBuf = new int[3];
+        byte[]      outBuf = new byte[3];
         int         bufPtr = 3;
         Crc24       crc = new Crc24();
         bool        crcFound = false;
@@ -498,7 +498,7 @@ namespace Org.BouncyCastle.Bcpg
 
             c = outBuf[bufPtr++];
 
-            crc.Update(c);
+            crc.Update((byte)c);
 
             return c;
         }
diff --git a/crypto/src/bcpg/Crc24.cs b/crypto/src/bcpg/Crc24.cs
index 5521bbb64..54c9f2f5a 100644
--- a/crypto/src/bcpg/Crc24.cs
+++ b/crypto/src/bcpg/Crc24.cs
@@ -2,39 +2,34 @@ using System;
 
 namespace Org.BouncyCastle.Bcpg
 {
-    public class Crc24
+    public sealed class Crc24
     {
         private const int Crc24Init = 0x0b704ce;
         private const int Crc24Poly = 0x1864cfb;
 
-        private int crc = Crc24Init;
+        private int m_crc = Crc24Init;
 
         public Crc24()
         {
         }
 
-        public void Update(
-            int b)
+        public void Update(byte b)
         {
-            crc ^= b << 16;
+            m_crc ^= (int)b << 16;
             for (int i = 0; i < 8; i++)
             {
-                crc <<= 1;
-                if ((crc & 0x1000000) != 0)
-                {
-                    crc ^= Crc24Poly;
-                }
+                int carry = -((m_crc >> 23) & 1) & Crc24Poly;
+
+                m_crc <<= 1;
+                m_crc ^= carry;
             }
         }
 
-		public int Value
-		{
-			get { return crc; }
-		}
+        public int Value => m_crc;
 
 		public void Reset()
         {
-            crc = Crc24Init;
+            m_crc = Crc24Init;
         }
     }
 }
-- 
cgit 1.4.1