| /* |
| [The "BSD license"] |
| Copyright (c) 2005-2009 Terence Parr |
| 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. |
| */ |
| package org.antlr.runtime; |
| |
| import org.antlr.runtime.misc.LookaheadStream; |
| |
| import java.util.List; |
| import java.util.NoSuchElementException; |
| |
| /** 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 extends LookaheadStream<Token> implements TokenStream { |
| protected TokenSource tokenSource; |
| protected int tokenIndex = 0; // 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 = Token.DEFAULT_CHANNEL; |
| |
| public UnbufferedTokenStream(TokenSource tokenSource) { |
| this.tokenSource = tokenSource; |
| } |
| |
| public Token nextElement() { |
| Token t = tokenSource.nextToken(); |
| t.setTokenIndex(tokenIndex++); |
| return t; |
| } |
| |
| public boolean isEOF(Token o) { return o.getType() == Token.EOF; } |
| |
| public TokenSource getTokenSource() { return tokenSource; } |
| |
| public String toString(int start, int stop) { return "n/a"; } |
| |
| public String toString(Token start, Token stop) { return "n/a"; } |
| |
| public int LA(int i) { return LT(i).getType(); } |
| |
| public Token get(int i) { |
| throw new UnsupportedOperationException("Absolute token indexes are meaningless in an unbuffered stream"); |
| } |
| |
| public String getSourceName() { return tokenSource.getSourceName(); } |
| } |