// The Nova Project by Ken Beckett.
// Copyright (C) 2007-2012 Inevitable Software, all rights reserved.
// Released under the Common Development and Distribution License, CDDL-1.0: http://opensource.org/licenses/cddl1.php
using System;
using Nova.Parsing;
namespace Nova.CodeDOM
{
/// <summary>
/// Performs a boolean XOR operation on two <see cref="Expression"/>s.
/// </summary>
public class BitwiseXor : BinaryBitwiseOperator
{
#region /* CONSTANTS */
/// <summary>
/// The internal name of the operator.
/// </summary>
public const string InternalName = NamePrefix + "ExclusiveOr";
#endregion
#region /* CONSTRUCTORS */
/// <summary>
/// Create a <see cref="BitwiseXor"/> operator.
/// </summary>
public BitwiseXor(Expression left, Expression right)
: base(left, right)
{ }
#endregion
#region /* PROPERTIES */
/// <summary>
/// The symbol associated with the operator.
/// </summary>
public override string Symbol
{
get { return ParseToken; }
}
#endregion
#region /* METHODS */
/// <summary>
/// The internal name of the <see cref="BinaryOperator"/>.
/// </summary>
public override string GetInternalName()
{
return InternalName;
}
#endregion
#region /* PARSING */
/// <summary>
/// The token used to parse the code object.
/// </summary>
public const string ParseToken = "^";
/// <summary>
/// The precedence of the operator.
/// </summary>
public const int Precedence = 360;
/// <summary>
/// True if the operator is left-associative, or false if it's right-associative.
/// </summary>
public const bool LeftAssociative = true;
internal static new void AddParsePoints()
{
Parser.AddOperatorParsePoint(ParseToken, Precedence, LeftAssociative, false, Parse);
}
/// <summary>
/// Parse a <see cref="BitwiseXor"/> operator.
/// </summary>
public static BitwiseXor Parse(Parser parser, CodeObject parent, ParseFlags flags)
{
return new BitwiseXor(parser, parent);
}
protected BitwiseXor(Parser parser, CodeObject parent)
: base(parser, parent)
{ }
/// <summary>
/// Get the precedence of the operator.
/// </summary>
public override int GetPrecedence()
{
return Precedence;
}
#endregion
#region /* RESOLVING */
/// <summary>
/// Perform a bitwise XOR of two constant objects.
/// Supported types are: string, bool, enum, decimal, double, float, ulong, long, uint, int, ushort, short, char, byte, sbyte.
/// </summary>
/// <returns>
/// The bitwise XOR of the two constants, using the appropriate result type, including promoting smaller
/// types to int. Returns null if the operation is invalid.
/// </returns>
protected override object EvaluateConstants(object leftConstant, object rightConstant)
{
// Check for null or string constants
if (leftConstant == null || rightConstant == null || leftConstant is string || rightConstant is string)
return null; // The operation is invalid
// Handle bool constants
if (leftConstant is bool || rightConstant is bool)
{
if (leftConstant is bool && rightConstant is bool)
return (bool)leftConstant ^ (bool)rightConstant;
return null; // The operation is invalid
}
// Handle enum constants
if (leftConstant is EnumConstant || rightConstant is EnumConstant)
{
// If both sides are enums, the result is an enum. If only one side is an enum, convert the
// enum operand to its constant value for the numeric calculations below.
if (leftConstant is EnumConstant)
{
EnumConstant leftEnum = (EnumConstant)leftConstant;
if (rightConstant is EnumConstant)
{
EnumConstant rightEnum = (EnumConstant)rightConstant;
if (leftEnum.EnumTypeRef.IsSameRef(rightEnum.EnumTypeRef))
return new EnumConstant(leftEnum.EnumTypeRef, EvaluateConstants(leftEnum.ConstantValue, rightEnum.ConstantValue));
return null;
}
leftConstant = leftEnum.ConstantValue;
}
else
rightConstant = ((EnumConstant)rightConstant).ConstantValue;
}
// Do binary numeric promotions
if (leftConstant is decimal || rightConstant is decimal || leftConstant is double || rightConstant is double
|| leftConstant is float || rightConstant is float)
return null; // The operation is invalid
if (leftConstant is ulong)
{
if ((rightConstant is sbyte && (sbyte)rightConstant < 0) || (rightConstant is short && (short)rightConstant < 0)
|| (rightConstant is int && (int)rightConstant < 0) || (rightConstant is long && (long)rightConstant < 0))
return null; // The operation is invalid
return (ulong)leftConstant ^ Convert.ToUInt64(rightConstant);
}
if (rightConstant is ulong)
{
if ((leftConstant is sbyte && (sbyte)leftConstant < 0) || (leftConstant is short && (short)leftConstant < 0)
|| (leftConstant is int && (int)leftConstant < 0) || (leftConstant is long && (long)leftConstant < 0))
return null; // The operation is invalid
return Convert.ToUInt64(leftConstant) ^ (ulong)rightConstant;
}
if (leftConstant is long)
return (long)leftConstant ^ Convert.ToInt64(rightConstant);
if (rightConstant is long)
return Convert.ToInt64(leftConstant) ^ (long)rightConstant;
if (leftConstant is uint)
{
if ((rightConstant is sbyte && (sbyte)rightConstant < 0) || (rightConstant is short && (short)rightConstant < 0)
|| (rightConstant is int && (int)rightConstant < 0))
return Convert.ToInt64(leftConstant) ^ Convert.ToInt64(rightConstant);
return (uint)leftConstant ^ Convert.ToUInt32(rightConstant);
}
if (rightConstant is uint)
{
if ((leftConstant is sbyte && (sbyte)leftConstant < 0) || (leftConstant is short && (short)leftConstant < 0)
|| (leftConstant is int && (int)leftConstant < 0))
return Convert.ToInt64(leftConstant) ^ Convert.ToInt64(rightConstant);
return Convert.ToUInt32(leftConstant) ^ (uint)rightConstant;
}
// All other cases (with smaller integral types) get promoted to ints
return Convert.ToInt32(leftConstant) ^ Convert.ToInt32(rightConstant);
}
#endregion
}
}