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//
// StringFunctions.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.Collections;
using System.Data;
namespace Mono.Data.SqlExpressions {
internal abstract class StringFunction : UnaryExpression {
protected StringFunction (IExpression e) : base (e) {}
override public object Eval (DataRow row)
{
object val = expr.Eval (row);
if(val == null)
return null;
if (!(val is string)) {
string fnct = this.GetType ().ToString ();
int start = fnct.LastIndexOf('.') + 1;
fnct = fnct.Substring (start, fnct.Length - start - "Function".Length);
throw new EvaluateException (String.Format ("'{0}' can be applied only to strings.", fnct));
}
return val;
}
}
internal class SubstringFunction : StringFunction {
int start, len;
public SubstringFunction (IExpression e, int start, int len) : base (e)
{
this.start = start;
this.len = len;
}
public override bool Equals(object obj)
{
if (!base.Equals (obj))
return false;
if (!(obj is SubstringFunction))
return false;
SubstringFunction other = (SubstringFunction) obj;
if (other.start != start)
return false;
if (other.len != len)
return false;
return true;
}
public override int GetHashCode()
{
int hashCode = base.GetHashCode ();
hashCode ^= start.GetHashCode ();
hashCode ^= len.GetHashCode ();
return hashCode;
}
override public object Eval (DataRow row)
{
string str = (string)base.Eval (row);
if(str == null)
return null;
if (start > str.Length)
return String.Empty;
return str.Substring (start - 1, System.Math.Min (len, str.Length - (start - 1)));
}
}
internal class LenFunction : StringFunction {
public LenFunction (IExpression e) : base (e) {}
override public object Eval (DataRow row)
{
string str = (string)base.Eval (row);
if(str == null)
return 0;
return str.Length;
}
}
internal class TrimFunction : StringFunction {
public TrimFunction (IExpression e) : base (e) {}
override public object Eval (DataRow row)
{
string str = (string)base.Eval (row);
if(str == null)
return null;
return str.Trim();
}
}
}
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