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//
// Comparison.cs
//
// Author:
// Juraj Skripsky (juraj@hotfeet.ch)
//
// (C) 2004 HotFeet GmbH (http://www.hotfeet.ch)
//
//
// Copyright (C) 2004 Novell, Inc (http://www.novell.com)
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
//
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
using System;
using System.Data;
using System.Threading;
using System.Globalization;
namespace Mono.Data.SqlExpressions {
internal class Comparison : BinaryOpExpression {
public Comparison (Operation op, IExpression e1, IExpression e2) : base (op, e1, e2) {}
override public object Eval (DataRow row)
{
return EvalBoolean (row);
}
public override bool EvalBoolean (DataRow row)
{
IComparable o1 = expr1.Eval (row) as IComparable;
IComparable o2 = expr2.Eval (row) as IComparable;
if (o1 == null || o2 == null) {
if (o1 == null && o2 == null)
return (op == Operation.EQ);
else
return (op == Operation.NE);
}
int result = Compare (o1, o2, row.Table.CaseSensitive);
if (result < 0) {
return (op == Operation.NE || op == Operation.LE || op == Operation.LT);
}
if (result > 0) {
return (op == Operation.NE || op == Operation.GE || op == Operation.GT);
}
// result == 0
return (op == Operation.EQ || op == Operation.LE || op == Operation.GE);
}
// certain trailing whitespace chars (including space) are ignored by .NET when comparing strings. See bug #79695.
private static readonly char[] IgnoredTrailingChars = { (char) 0x20, (char) 0x3000, (char) 0xFEFF };
internal static int Compare (IComparable o1, IComparable o2, bool caseSensitive)
{
//TODO: turn this "conversion pipeline" into something nicer
try {
if (o1 is string && Numeric.IsNumeric (o2))
o1 = (IComparable) Convert.ChangeType (o1, o2.GetType ());
else if (o2 is string && Numeric.IsNumeric (o1))
o2 = (IComparable) Convert.ChangeType (o2, o1.GetType ());
else if (o1 is string && o2 is Guid)
o2 = o2.ToString ();
else if (o2 is string && o1 is Guid)
o1 = o1.ToString ();
} catch (FormatException) {
throw new EvaluateException (String.Format ("Cannot perform compare operation on {0} and {1}.", o1.GetType(), o2.GetType()));
}
if (o1 is string && o2 is string) {
o1 = ((string) o1).TrimEnd (IgnoredTrailingChars);
o2 = ((string) o2).TrimEnd (IgnoredTrailingChars);
if (!caseSensitive) {
o1 = ((string) o1).ToLower ();
o2 = ((string) o2).ToLower ();
}
}
if (o1 is DateTime && o2 is string && Thread.CurrentThread.CurrentCulture != CultureInfo.InvariantCulture) {
// DateTime is always CultureInfo.InvariantCulture
o2 = (IComparable) DateTime.Parse ((string)o2, CultureInfo.InvariantCulture);
} else if (o2 is DateTime && o1 is string &&
Thread.CurrentThread.CurrentCulture != CultureInfo.InvariantCulture) {
// DateTime is always CultureInfo.InvariantCulture
o1 = (IComparable) DateTime.Parse ((string)o1, CultureInfo.InvariantCulture);
}
else if (o2 is DateTime && o1 is string && Thread.CurrentThread.CurrentCulture != CultureInfo.InvariantCulture) {
// DateTime is always CultureInfo.InvariantCulture
o1 = (IComparable) DateTime.Parse ((string)o1, CultureInfo.InvariantCulture);
}
if (o1.GetType () != o2.GetType ())
o2 = (IComparable)Convert.ChangeType (o2, o1.GetType ());
return o1.CompareTo (o2);
}
}
}
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