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Viewing changes to lib/antlr/src/TokenStreamSelector.cpp

  • Committer: Bazaar Package Importer
  • Author(s): Jeremy Lainé
  • Date: 2006-05-23 18:39:42 UTC
  • Revision ID: james.westby@ubuntu.com-20060523183942-hucifbvh68k2bwz7
Tags: upstream-3.3.2
Import upstream version 3.3.2

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lib/antlr/src/TokenStreamSelector.cpp
 
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/* ANTLR Translator Generator
 
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 * Project led by Terence Parr at http://www.jGuru.com
 
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 * Software rights: http://www.antlr.org/RIGHTS.html
 
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 *
 
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 */
 
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#include "antlr/TokenStreamSelector.hpp"
 
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#include "antlr/TokenStreamRetryException.hpp"
 
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#ifdef ANTLR_CXX_SUPPORTS_NAMESPACE
 
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namespace antlr {
 
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#endif
 
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/** A token stream MUX (multiplexor) knows about n token streams
 
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 *  and can multiplex them onto the same channel for use by token
 
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 *  stream consumer like a parser.  This is a way to have multiple
 
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 *  lexers break up the same input stream for a single parser.
 
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 *      Or, you can have multiple instances of the same lexer handle
 
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 *  multiple input streams; this works great for includes.
 
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 */
 
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TokenStreamSelector::TokenStreamSelector()
 
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: input(0)
 
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{
 
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}
 
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TokenStreamSelector::~TokenStreamSelector()
 
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{
 
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}
 
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void TokenStreamSelector::addInputStream(TokenStream* stream, const ANTLR_USE_NAMESPACE(std)string& key)
 
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{
 
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        inputStreamNames[key] = stream;
 
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}
 
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TokenStream* TokenStreamSelector::getCurrentStream() const
 
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{
 
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        return input;
 
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}
 
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TokenStream* TokenStreamSelector::getStream(const ANTLR_USE_NAMESPACE(std)string& sname) const
 
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{
 
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        inputStreamNames_coll::const_iterator i = inputStreamNames.find(sname);
 
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        if (i == inputStreamNames.end()) {
 
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                throw ANTLR_USE_NAMESPACE(std)string("TokenStream ")+sname+" not found";
 
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        }
 
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        return (*i).second;
 
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}
 
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RefToken TokenStreamSelector::nextToken()
 
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{
 
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        // keep looking for a token until you don't
 
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        // get a retry exception
 
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        for (;;) {
 
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                try {
 
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                        return input->nextToken();
 
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                }
 
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                catch (TokenStreamRetryException& r) {
 
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                        // just retry "forever"
 
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                }
 
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        }
 
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}
 
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TokenStream* TokenStreamSelector::pop()
 
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{
 
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        TokenStream* stream = streamStack.top();
 
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        streamStack.pop();
 
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        select(stream);
 
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        return stream;
 
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}
 
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void TokenStreamSelector::push(TokenStream* stream)
 
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{
 
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        streamStack.push(input);
 
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        select(stream);
 
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}
 
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void TokenStreamSelector::push(const ANTLR_USE_NAMESPACE(std)string& sname)
 
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{
 
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        streamStack.push(input);
 
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        select(sname);
 
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}
 
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void TokenStreamSelector::retry()
 
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{
 
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        throw TokenStreamRetryException();
 
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}
 
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/** Set the stream without pushing old stream */
 
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void TokenStreamSelector::select(TokenStream* stream)
 
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{
 
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        input = stream;
 
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}
 
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void TokenStreamSelector::select(const ANTLR_USE_NAMESPACE(std)string& sname)
 
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{
 
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        inputStreamNames_coll::const_iterator i = inputStreamNames.find(sname);
 
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        if (i == inputStreamNames.end()) {
 
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                throw ANTLR_USE_NAMESPACE(std)string("TokenStream ")+sname+" not found";
 
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        }
 
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        input = (*i).second;
 
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}
 
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#ifdef ANTLR_CXX_SUPPORTS_NAMESPACE
 
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}
 
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#endif
 
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