#ifndef INC_TokenBuffer_hpp__ #define INC_TokenBuffer_hpp__ /** * SOFTWARE RIGHTS *

* ANTLR 2.6.0 MageLang Insitute, 1999 *

* We reserve no legal rights to the ANTLR--it is fully in the * public domain. An individual or company may do whatever * they wish with source code distributed with ANTLR or the * code generated by ANTLR, including the incorporation of * ANTLR, or its output, into commerical software. *

* We encourage users to develop software with ANTLR. However, * we do ask that credit is given to us for developing * ANTLR. By "credit", we mean that if you use ANTLR or * incorporate any source code into one of your programs * (commercial product, research project, or otherwise) that * you acknowledge this fact somewhere in the documentation, * research report, etc... If you like ANTLR and have * developed a nice tool with the output, please mention that * you developed it using ANTLR. In addition, we ask that the * headers remain intact in our source code. As long as these * guidelines are kept, we expect to continue enhancing this * system and expect to make other tools available as they are * completed. *

* The ANTLR gang: * @version ANTLR 2.6.0 MageLang Insitute, 1999 * @author Terence Parr, MageLang Institute * @author
John Lilley, Empathy Software * @author
Pete Wells */ #include "antlr/config.h" #include "antlr/TokenStream.h" #include "antlr/CircularQueue.h" ANTLR_BEGIN_NAMESPACE(antlr) /**A Stream of Token objects fed to the parser from a TokenStream that can * be rewound via mark()/rewind() methods. *

* A dynamic array is used to buffer up all the input tokens. Normally, * "k" tokens are stored in the buffer. More tokens may be stored during * guess mode (testing syntactic predicate), or when LT(i>k) is referenced. * Consumption of tokens is deferred. In other words, reading the next * token is not done by conume(), but deferred until needed by LA or LT. *

* * @see antlr.Token * @see antlr.TokenStream * @see antlr.TokenQueue */ class TokenBuffer { protected: // Token source TokenStream& input; private: // Number of active markers int nMarkers; // Additional offset used when markers are active int markerOffset; // Number of calls to consume() since last LA() or LT() call int numToConsume; // Circular queue CircularQueue queue; public: /** Create a token buffer */ TokenBuffer(TokenStream& input_); /** Mark another token for deferred consumption */ void consume(); private: /** Ensure that the token buffer is sufficiently full */ void fill(int amount); public: /** Get a lookahead token value */ int LA(int i); /** Get a lookahead token */ RefToken LT(int i); /**Return an integer marker that can be used to rewind the buffer to * its current state. */ int mark(); /**Rewind the token buffer to a marker. * @param mark Marker returned previously from mark() */ void rewind(int mark); private: /** Sync up deferred consumption */ void syncConsume(); private: TokenBuffer(const TokenBuffer& other); const TokenBuffer& operator=(const TokenBuffer& other); public: // virtual ~TokenBuffer() {} }; /** Sync up deferred consumption */ inline void TokenBuffer::syncConsume() { #ifdef OLD_CODE while (numToConsume > 0) { if (nMarkers > 0) { // guess mode -- leave leading tokens and bump offset. markerOffset++; } else { // normal mode -- remove first token queue.removeFirst(); } numToConsume--; } #endif if (numToConsume > 0) { if (nMarkers > 0) { markerOffset += numToConsume; } else { queue.removeItems( numToConsume ); } numToConsume = 0; } } ANTLR_END_NAMESPACE #endif //INC_TokenBuffer_hpp__