// 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.Runtime.InteropServices;
using Nova.Parsing;
namespace Nova.CodeDOM
{
/// <summary>
/// Returns the size of the specified type.
/// </summary>
/// <remarks>
/// This operator works only for value types, and can only be used in an unsafe context except
/// for primitive integral types. <see cref="Marshal.SizeOf(object)"/> can be used instead, but this size might
/// vary from 'sizeof', because it won't include any padding used by the CLR.
/// </remarks>
public class SizeOf : TypeOperator
{
#region /* CONSTRUCTORS */
/// <summary>
/// Create a <see cref="SizeOf"/> operator.
/// </summary>
/// <param name="type">A TypeRef or an expression that evaluates to one.</param>
public SizeOf(Expression type)
: base(type)
{ }
#endregion
#region /* PROPERTIES */
/// <summary>
/// The symbol associated with the operator.
/// </summary>
public override string Symbol
{
get { return ParseToken; }
}
/// <summary>
/// True if the expression is const.
/// </summary>
public override bool IsConst
{
get { return true; }
}
#endregion
#region /* PARSING */
/// <summary>
/// The token used to parse the code object.
/// </summary>
public const string ParseToken = "sizeof";
/// <summary>
/// The precedence of the operator.
/// </summary>
public const int Precedence = 100;
/// <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="SizeOf"/> operator.
/// </summary>
public static SizeOf Parse(Parser parser, CodeObject parent, ParseFlags flags)
{
return new SizeOf(parser, parent);
}
protected SizeOf(Parser parser, CodeObject parent)
: base(parser, parent)
{
ParseKeywordAndArgument(parser, ParseFlags.Type);
}
/// <summary>
/// Get the precedence of the operator.
/// </summary>
public override int GetPrecedence()
{
return Precedence;
}
#endregion
#region /* RESOLVING */
/// <summary>
/// Evaluate the type of the <see cref="Expression"/>.
/// </summary>
/// <returns>The resulting <see cref="TypeRef"/> or <see cref="UnresolvedRef"/>.</returns>
public override TypeRefBase EvaluateType(bool withoutConstants)
{
// The following built-in types result in constant sizes outside of unsafe code blocks:
TypeRefBase typeRefBase = _expression.EvaluateType(withoutConstants);
if (typeRefBase.IsSameRef(TypeRef.BoolRef) || typeRefBase.IsSameRef(TypeRef.SByteRef) || typeRefBase.IsSameRef(TypeRef.ByteRef))
return new TypeRef(TypeRef.IntRef, 1);
if (typeRefBase.IsSameRef(TypeRef.CharRef) || typeRefBase.IsSameRef(TypeRef.ShortRef) || typeRefBase.IsSameRef(TypeRef.UShortRef))
return new TypeRef(TypeRef.IntRef, 2);
if (typeRefBase.IsSameRef(TypeRef.IntRef) || typeRefBase.IsSameRef(TypeRef.UIntRef) || typeRefBase.IsSameRef(TypeRef.FloatRef))
return new TypeRef(TypeRef.IntRef, 4);
if (typeRefBase.IsSameRef(TypeRef.LongRef) || typeRefBase.IsSameRef(TypeRef.ULongRef) || typeRefBase.IsSameRef(TypeRef.DoubleRef))
return new TypeRef(TypeRef.IntRef, 8);
if (typeRefBase.IsSameRef(TypeRef.DecimalRef))
return new TypeRef(TypeRef.IntRef, 16);
// Otherwise, just return 'int'
return TypeRef.IntRef;
}
#endregion
}
}