| /* |
| * [The "BSD licence"] |
| * Copyright (c) 2005-2008 Terence Parr |
| * All rights reserved. |
| * |
| * Conversion to C#: |
| * Copyright (c) 2009 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. |
| */ |
| |
| namespace Antlr.Runtime |
| { |
| using Antlr.Runtime.Misc; |
| using CLSCompliant = System.CLSCompliantAttribute; |
| using NotSupportedException = System.NotSupportedException; |
| using IndexOutOfRangeException = System.IndexOutOfRangeException; |
| |
| /** A token stream that pulls tokens from the code source on-demand and |
| * without tracking a complete buffer of the tokens. This stream buffers |
| * the minimum number of tokens possible. It's the same as |
| * OnDemandTokenStream except that OnDemandTokenStream buffers all tokens. |
| * |
| * You can't use this stream if you pass whitespace or other off-channel |
| * tokens to the parser. The stream can't ignore off-channel tokens. |
| * |
| * You can only look backwards 1 token: LT(-1). |
| * |
| * Use this when you need to read from a socket or other infinite stream. |
| * |
| * @see BufferedTokenStream |
| * @see CommonTokenStream |
| */ |
| public class UnbufferedTokenStream : LookaheadStream<IToken>, ITokenStream, ITokenStreamInformation |
| { |
| [CLSCompliant(false)] |
| protected ITokenSource tokenSource; |
| protected int tokenIndex; // simple counter to set token index in tokens |
| |
| /** Skip tokens on any channel but this one; this is how we skip whitespace... */ |
| protected int channel = TokenChannels.Default; |
| |
| private readonly ListStack<IToken> _realTokens = new ListStack<IToken>() { null }; |
| |
| public UnbufferedTokenStream(ITokenSource tokenSource) |
| { |
| this.tokenSource = tokenSource; |
| } |
| |
| public ITokenSource TokenSource |
| { |
| get |
| { |
| return this.tokenSource; |
| } |
| } |
| |
| public string SourceName |
| { |
| get |
| { |
| return TokenSource.SourceName; |
| } |
| } |
| |
| #region ITokenStreamInformation Members |
| |
| public IToken LastToken |
| { |
| get |
| { |
| return LB(1); |
| } |
| } |
| |
| public IToken LastRealToken |
| { |
| get |
| { |
| return _realTokens.Peek(); |
| } |
| } |
| |
| public int MaxLookBehind |
| { |
| get |
| { |
| return 1; |
| } |
| } |
| |
| public override int Mark() |
| { |
| _realTokens.Push(_realTokens.Peek()); |
| return base.Mark(); |
| } |
| |
| public override void Release(int marker) |
| { |
| base.Release(marker); |
| _realTokens.Pop(); |
| } |
| |
| public override void Clear() |
| { |
| _realTokens.Clear(); |
| _realTokens.Push(null); |
| } |
| |
| public override void Consume() |
| { |
| base.Consume(); |
| if (PreviousElement != null && PreviousElement.Line > 0) |
| _realTokens[_realTokens.Count - 1] = PreviousElement; |
| } |
| |
| #endregion |
| |
| public override IToken NextElement() |
| { |
| IToken t = this.tokenSource.NextToken(); |
| t.TokenIndex = this.tokenIndex++; |
| return t; |
| } |
| |
| public override bool IsEndOfFile(IToken o) |
| { |
| return o.Type == CharStreamConstants.EndOfFile; |
| } |
| |
| public IToken Get(int i) |
| { |
| throw new NotSupportedException("Absolute token indexes are meaningless in an unbuffered stream"); |
| } |
| |
| public int LA(int i) |
| { |
| return LT(i).Type; |
| } |
| |
| public string ToString(int start, int stop) |
| { |
| return "n/a"; |
| } |
| |
| public string ToString(IToken start, IToken stop) |
| { |
| return "n/a"; |
| } |
| } |
| } |