feat: Gray Code

jirikostiha · Jun 5, 2023 · bd765ce · bd765ce
1 parent fda0ca1
commit bd765ce
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diff --git a/src/code/SMath/BinaryIntegerExtension.cs b/src/code/SMath/BinaryIntegerExtension.cs
@@ -24,5 +24,24 @@ public static N HammingDistanceTo<N>(this N number, N otherNumber)
 
             return setBits;
         }
+
+        public static N ToGrayCode<N>(this N number)
+            where N : IBinaryInteger<N>, IUnsignedNumber<N>
+            => number ^ (number >> 1);
+
+        public static N FromGrayCode<N>(this N gray)
+            where N : IBinaryInteger<N>, IUnsignedNumber<N>
+        {
+            var n = gray;
+            var result = n;
+
+            while (n > N.Zero)
+            {
+                n >>= 1;
+                result ^= n;
+            }
+
+            return result;
+        }
     }
 }
diff --git a/src/quality/SMath__Tests/BinaryIntegerExtensionTests.cs b/src/quality/SMath__Tests/BinaryIntegerExtensionTests.cs
@@ -31,5 +31,49 @@ public void HammingDistance_Byte(byte n1, byte n2, byte distance)
         {
             Assert.Equal(distance, n1.HammingDistanceTo(n2));
         }
+
+        [Theory]
+        [InlineData(1, 1)]
+        [InlineData(2, 3)]
+        [InlineData(3, 2)]
+        [InlineData(7, 4)]
+        [InlineData(15, 8)]
+        public void ToGrayCode_Byte(byte number, byte gray)
+        {
+            Assert.Equal(gray, number.ToGrayCode());
+        }
+
+        [Theory]
+        [InlineData(1, 1)]
+        [InlineData(2, 3)]
+        [InlineData(3, 2)]
+        [InlineData(7, 4)]
+        [InlineData(15, 8)]
+        public void ToGrayCode_Int(uint number, uint gray)
+        {
+            Assert.Equal(gray, number.ToGrayCode());
+        }
+
+        [Theory]
+        [InlineData(1, 1)]
+        [InlineData(3, 2)]
+        [InlineData(2, 3)]
+        [InlineData(4, 7)]
+        [InlineData(8, 15)]
+        public void FromGrayCode_Byte(byte gray, byte number)
+        {
+            Assert.Equal(number, gray.FromGrayCode());
+        }
+
+        [Theory]
+        [InlineData(1, 1)]
+        [InlineData(3, 2)]
+        [InlineData(2, 3)]
+        [InlineData(4, 7)]
+        [InlineData(8, 15)]
+        public void FromGrayCode_Int(uint gray, uint number)
+        {
+            Assert.Equal(number, gray.FromGrayCode());
+        }
     }
 }