123 lines
3.3 KiB
C#
123 lines
3.3 KiB
C#
//-----------------------------------------------------------------------------
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// Copyright (c) Microsoft Corporation. All rights reserved.
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//-----------------------------------------------------------------------------
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namespace System.Runtime.Serialization
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{
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using System;
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using System.Reflection;
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#if !NO_DYNAMIC_CODEGEN
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using System.Reflection.Emit;
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#endif
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using System.Security;
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[Fx.Tag.SecurityNote(Miscellaneous = "RequiresReview (Critical) - works on CodeGenerator objects, which require Critical access.")]
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class BitFlagsGenerator
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{
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#if !NO_DYNAMIC_CODEGEN
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int bitCount;
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CodeGenerator ilg;
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LocalBuilder[] locals;
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public BitFlagsGenerator(int bitCount, CodeGenerator ilg, string localName)
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{
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this.ilg = ilg;
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this.bitCount = bitCount;
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int localCount = (bitCount + 7) / 8;
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locals = new LocalBuilder[localCount];
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for (int i = 0; i < locals.Length; i++)
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{
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locals[i] = ilg.DeclareLocal(typeof(byte), localName + i, (byte) 0);
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}
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}
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#endif
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public static bool IsBitSet(byte[] bytes, int bitIndex)
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{
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int byteIndex = GetByteIndex(bitIndex);
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byte bitValue = GetBitValue(bitIndex);
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return (bytes[byteIndex] & bitValue) == bitValue;
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}
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public static void SetBit(byte[] bytes, int bitIndex)
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{
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int byteIndex = GetByteIndex(bitIndex);
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byte bitValue = GetBitValue(bitIndex);
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bytes[byteIndex] |= bitValue;
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}
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#if !NO_DYNAMIC_CODEGEN
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public int GetBitCount()
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{
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return bitCount;
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}
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public LocalBuilder GetLocal(int i)
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{
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return locals[i];
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}
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public int GetLocalCount()
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{
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return locals.Length;
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}
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public void Load(int bitIndex)
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{
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LocalBuilder local = locals[GetByteIndex(bitIndex)];
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byte bitValue = GetBitValue(bitIndex);
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ilg.Load(local);
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ilg.Load(bitValue);
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ilg.And();
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ilg.Load(bitValue);
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ilg.Ceq();
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}
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public void LoadArray()
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{
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LocalBuilder localArray = ilg.DeclareLocal(Globals.TypeOfByteArray, "localArray");
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ilg.NewArray(typeof(byte), locals.Length);
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ilg.Store(localArray);
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for (int i = 0; i < locals.Length; i++)
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{
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ilg.StoreArrayElement(localArray, i, locals[i]);
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}
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ilg.Load(localArray);
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}
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public void Store(int bitIndex, bool value)
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{
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LocalBuilder local = locals[GetByteIndex(bitIndex)];
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byte bitValue = GetBitValue(bitIndex);
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if (value)
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{
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ilg.Load(local);
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ilg.Load(bitValue);
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ilg.Or();
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ilg.Stloc(local);
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}
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else
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{
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ilg.Load(local);
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ilg.Load(bitValue);
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ilg.Not();
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ilg.And();
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ilg.Stloc(local);
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}
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}
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#endif
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static byte GetBitValue(int bitIndex)
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{
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return (byte)(1 << (bitIndex & 7));
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}
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static int GetByteIndex(int bitIndex)
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{
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return bitIndex >> 3;
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}
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}
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}
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