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[pccts] / h / ATokenBuffer.h

diff --git a/h/ATokenBuffer.h b/h/ATokenBuffer.h
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+/* ANTLRTokenBuffer.h
+ *
+ * SOFTWARE RIGHTS
+ *
+ * We reserve no LEGAL rights to the Purdue Compiler Construction Tool
+ * Set (PCCTS) -- PCCTS is in the public domain.  An individual or
+ * company may do whatever they wish with source code distributed with
+ * PCCTS or the code generated by PCCTS, including the incorporation of
+ * PCCTS, or its output, into commerical software.
+ * 
+ * We encourage users to develop software with PCCTS.  However, we do ask
+ * that credit is given to us for developing PCCTS.  By "credit",
+ * we mean that if you incorporate our 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 PCCTS and have developed a nice tool with the
+ * output, please mention that you developed it using PCCTS.  In
+ * addition, we ask that this header 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.
+ *
+ * ANTLR 1.33
+ * Terence Parr
+ * Parr Research Corporation
+ * with Purdue University and AHPCRC, University of Minnesota
+ * 1989-1995
+ */
+
+#ifndef ATOKENBUFFER_H_GATE
+#define ATOKENBUFFER_H_GATE
+
+#include "config.h"
+#include ATOKEN_H
+#include ATOKENSTREAM_H
+#include <stdlib.h>
+
+/*
+ * The parser is "attached" to an ANTLRTokenBuffer via interface
+ * functions: getToken() and bufferedToken().  The object that actually
+ * consumes characters and constructs tokens is connected to the
+ * ANTLRTokenBuffer via interface function ANTLRTokenStream::getToken();
+ * where ANTLRTokenStream is really just a behavior (class with no data).
+ * C++ does not have this abstraction and hence we simply have come up
+ * with a fancy name for "void *".  See the note in ANTLRTokenStream.h on
+ * the "behavior" of ANTLRTokenStream.
+ */
+
+class ANTLRTokenBuffer {
+protected:
+       ANTLRTokenStream *input;        // where do I get tokens
+       int buffer_size;
+       int chunk_size;
+       int num_markers;
+       int k;                          // Need at least this many tokens in buffer
+       _ANTLRTokenPtr *buffer; // buffer used for arbitrary lookahead
+       _ANTLRTokenPtr *tp;        // pts into buffer; current token ptr
+       _ANTLRTokenPtr *last;      // pts to last valid token in buffer
+       _ANTLRTokenPtr *next;      // place to put token from getANTLRToken()
+       _ANTLRTokenPtr *end_of_buffer;
+       /* when you try to write a token past this and there are no markers
+          set, then move k-1 tokens back to the beginning of the buffer.
+          We want to stay away from the end of the buffer because we have
+          to extend it if a marker is set and we reach the end (we cannot
+          move tokens to the beginning of the buffer in this case).
+        */
+       _ANTLRTokenPtr *threshold;
+       unsigned char _deleteTokens;
+
+       // This function is filled in by the subclass; it initiates fetch of input
+       virtual _ANTLRTokenPtr getANTLRToken() { return input->getToken(); }
+       void makeRoom();
+       void extendBuffer();
+
+public:
+       ANTLRTokenBuffer(ANTLRTokenStream *in, int k=1, int chksz=50);
+       virtual ~ANTLRTokenBuffer();
+       virtual _ANTLRTokenPtr getToken();
+       virtual void rewind(int pos);
+       virtual int mark();
+       virtual _ANTLRTokenPtr bufferedToken(int i);
+
+       void noGarbageCollectTokens()   { _deleteTokens=0; }
+       void garbageCollectTokens()             { _deleteTokens=1; }
+
+       virtual bufferSize() { return buffer_size; }
+       virtual int minTokens() { return k; }
+       virtual void setMinTokens(int k_new) { k = k_new; }
+
+       virtual void panic(char *msg) { exit(PCCTS_EXIT_FAILURE); }
+};
+
+#endif