/** * SOFTWARE RIGHTS *

* ANTLR 2.6.0 MageLang Insitute, 1998 *

* 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, 1998 * @author Terence Parr, MageLang Institute * @author
John Lilley, Empathy Software * @author
Pete Wells */ #include "antlr/TokenBuffer.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 */ /** Create a token buffer */ TokenBuffer::TokenBuffer(TokenStream& input_) : input(input_) { nMarkers=0; markerOffset=0; numToConsume=0; } /** Mark another token for deferred consumption */ void TokenBuffer::consume() { numToConsume++; } /** Ensure that the token buffer is sufficiently full */ void TokenBuffer::fill(int amount) { syncConsume(); // Fill the buffer sufficiently to hold needed tokens while (queue.entries() < amount + markerOffset) { // Append the next token queue.append(input.nextToken()); } } /** Get a lookahead token value */ int TokenBuffer::LA(int i) { fill(i); return queue.elementAt(markerOffset+i-1)->type; } /** Get a lookahead token */ RefToken TokenBuffer::LT(int i) { fill(i); return queue.elementAt(markerOffset+i-1); } /**Return an integer marker that can be used to rewind the buffer to * its current state. */ int TokenBuffer::mark() { syncConsume(); nMarkers++; return markerOffset; } /**Rewind the token buffer to a marker. * @param mark Marker returned previously from mark() */ void TokenBuffer::rewind(int mark) { syncConsume(); markerOffset=mark; nMarkers--; } ANTLR_END_NAMESPACE