antlr/Antlr4.Runtime/Atn/EmptyPredictionContext.cs

137 lines
3.6 KiB
C#

/*
* [The "BSD license"]
* Copyright (c) 2013 Terence Parr
* Copyright (c) 2013 Sam Harwell
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
using System;
using Antlr4.Runtime;
using Antlr4.Runtime.Atn;
using Sharpen;
namespace Antlr4.Runtime.Atn
{
public sealed class EmptyPredictionContext : PredictionContext
{
public static readonly Antlr4.Runtime.Atn.EmptyPredictionContext LocalContext = new
Antlr4.Runtime.Atn.EmptyPredictionContext(false);
public static readonly Antlr4.Runtime.Atn.EmptyPredictionContext FullContext = new
Antlr4.Runtime.Atn.EmptyPredictionContext(true);
private readonly bool fullContext;
private EmptyPredictionContext(bool fullContext) : base(CalculateHashCode(CalculateEmptyParentHashCode
(), CalculateEmptyReturnStateHashCode()))
{
this.fullContext = fullContext;
}
public bool IsFullContext()
{
return fullContext;
}
protected internal override PredictionContext AddEmptyContext()
{
return this;
}
protected internal override PredictionContext RemoveEmptyContext()
{
throw new NotSupportedException("Cannot remove the empty context from itself.");
}
public override PredictionContext GetParent(int index)
{
throw new IndexOutOfRangeException();
}
public override int GetReturnState(int index)
{
throw new IndexOutOfRangeException();
}
public override int FindReturnState(int returnState)
{
return -1;
}
public override int Size
{
get
{
return 0;
}
}
public override PredictionContext AppendContext(int returnContext, PredictionContextCache
contextCache)
{
return contextCache.GetChild(this, returnContext);
}
public override PredictionContext AppendContext(PredictionContext suffix, PredictionContextCache
contextCache)
{
return suffix;
}
public override bool IsEmpty
{
get
{
return true;
}
}
public override bool HasEmpty
{
get
{
return true;
}
}
public override bool Equals(object o)
{
return this == o;
}
public override string[] ToStrings<_T0>(Recognizer<_T0> recognizer, int currentState
)
{
return new string[] { "[]" };
}
public override string[] ToStrings<_T0>(Recognizer<_T0> recognizer, PredictionContext
stop, int currentState)
{
return new string[] { "[]" };
}
}
}