Imported Upstream version 4.2.0.179

Former-commit-id: 4610231f55806d2a05ed69e5ff3faa7336cc1479

mcs/class/System.Runtime.Serialization/ReferenceSources/BitFlagsGenerator.cs

@@ -0,0 +1,76 @@
+using System;
+
+namespace System.Runtime.Serialization
+{
+	class BitFlagsGenerator
+	{
+		int bitCount;
+		byte [] locals;
+		
+		public BitFlagsGenerator (int bitCount)
+		{
+			this.bitCount = bitCount;
+			int localCount = (bitCount+7)/8;
+			locals = new byte [localCount];
+		}
+		
+		public void Store (int bitIndex, bool value)
+		{
+			if (value)
+				locals [GetByteIndex (bitIndex)] |= GetBitValue(bitIndex);
+			else
+				locals [GetByteIndex (bitIndex)] &= (byte) ~GetBitValue(bitIndex);
+		}
+		
+		public bool Load (int bitIndex)
+		{
+			var local = locals[GetByteIndex(bitIndex)];
+			byte bitValue = GetBitValue(bitIndex);
+			return (local & bitValue) == bitValue;
+		}
+		
+		public byte [] LoadArray ()
+		{
+			return (byte []) locals.Clone ();
+		}
+		
+		public int GetLocalCount ()
+		{
+			return locals.Length;
+		}
+		
+		public int GetBitCount ()
+		{
+			return bitCount;
+		}
+		
+		public byte GetLocal (int i)
+		{
+			return locals [i];
+		}
+		
+		public static bool IsBitSet (byte[] bytes, int bitIndex)
+		{
+			int byteIndex = GetByteIndex (bitIndex);
+			byte bitValue = GetBitValue (bitIndex);
+			return (bytes[byteIndex] & bitValue) == bitValue;
+		}
+
+		public static void SetBit (byte[] bytes, int bitIndex)
+		{
+			int byteIndex = GetByteIndex (bitIndex);
+			byte bitValue = GetBitValue (bitIndex);
+			bytes[byteIndex] |= bitValue;
+		}
+
+		static int GetByteIndex (int bitIndex)
+		{
+			return bitIndex >> 3;
+		}
+		
+		static byte GetBitValue (int bitIndex)
+		{
+			return (byte)(1 << (bitIndex & 7));
+		}
+	}
+}