1 /* 2 * [The "BSD licence"] 3 * Copyright (c) 2005-2008 Terence Parr 4 * All rights reserved. 5 * 6 * Conversion to C#: 7 * Copyright (c) 2009 Sam Harwell 8 * All rights reserved. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. The name of the author may not be used to endorse or promote products 19 * derived from this software without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 22 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 23 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 24 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 26 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 27 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 28 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 29 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 30 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 31 */ 32 33 namespace Antlr.Runtime { 34 using Antlr.Runtime.Misc; 35 using CLSCompliant = System.CLSCompliantAttribute; 36 using NotSupportedException = System.NotSupportedException; 37 using IndexOutOfRangeException = System.IndexOutOfRangeException; 38 39 /** A token stream that pulls tokens from the code source on-demand and 40 * without tracking a complete buffer of the tokens. This stream buffers 41 * the minimum number of tokens possible. It's the same as 42 * OnDemandTokenStream except that OnDemandTokenStream buffers all tokens. 43 * 44 * You can't use this stream if you pass whitespace or other off-channel 45 * tokens to the parser. The stream can't ignore off-channel tokens. 46 * 47 * You can only look backwards 1 token: LT(-1). 48 * 49 * Use this when you need to read from a socket or other infinite stream. 50 * 51 * @see BufferedTokenStream 52 * @see CommonTokenStream 53 */ 54 public class UnbufferedTokenStream : LookaheadStream<IToken>, ITokenStream { 55 [CLSCompliant(false)] 56 protected ITokenSource tokenSource; 57 protected int tokenIndex; // simple counter to set token index in tokens 58 59 /** Skip tokens on any channel but this one; this is how we skip whitespace... */ 60 protected int channel = TokenChannels.Default; 61 UnbufferedTokenStream(ITokenSource tokenSource)62 public UnbufferedTokenStream(ITokenSource tokenSource) { 63 this.tokenSource = tokenSource; 64 } 65 66 public ITokenSource TokenSource { 67 get { 68 return this.tokenSource; 69 } 70 } 71 72 public string SourceName { 73 get { 74 return TokenSource.SourceName; 75 } 76 } 77 NextElement()78 public override IToken NextElement() { 79 IToken t = this.tokenSource.NextToken(); 80 t.TokenIndex = this.tokenIndex++; 81 return t; 82 } 83 IsEndOfFile(IToken o)84 public override bool IsEndOfFile(IToken o) { 85 return o.Type == CharStreamConstants.EndOfFile; 86 } 87 Get(int i)88 public IToken Get(int i) { 89 throw new NotSupportedException("Absolute token indexes are meaningless in an unbuffered stream"); 90 } 91 LA(int i)92 public int LA(int i) { 93 return LT(i).Type; 94 } 95 ToString(int start, int stop)96 public string ToString(int start, int stop) { 97 return "n/a"; 98 } 99 ToString(IToken start, IToken stop)100 public string ToString(IToken start, IToken stop) { 101 return "n/a"; 102 } 103 } 104 } 105