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00001 /* ANTLRTokenBuffer.h 00002 * 00003 * SOFTWARE RIGHTS 00004 * 00005 * We reserve no LEGAL rights to the Purdue Compiler Construction Tool 00006 * Set (PCCTS) -- PCCTS is in the public domain. An individual or 00007 * company may do whatever they wish with source code distributed with 00008 * PCCTS or the code generated by PCCTS, including the incorporation of 00009 * PCCTS, or its output, into commerical software. 00010 * 00011 * We encourage users to develop software with PCCTS. However, we do ask 00012 * that credit is given to us for developing PCCTS. By "credit", 00013 * we mean that if you incorporate our source code into one of your 00014 * programs (commercial product, research project, or otherwise) that you 00015 * acknowledge this fact somewhere in the documentation, research report, 00016 * etc... If you like PCCTS and have developed a nice tool with the 00017 * output, please mention that you developed it using PCCTS. In 00018 * addition, we ask that this header remain intact in our source code. 00019 * As long as these guidelines are kept, we expect to continue enhancing 00020 * this system and expect to make other tools available as they are 00021 * completed. 00022 * 00023 * ANTLR 1.33 00024 * Terence Parr 00025 * Parr Research Corporation 00026 * with Purdue University and AHPCRC, University of Minnesota 00027 * 1989-1998 00028 */ 00029 00030 #ifndef ATOKENBUFFER_H_GATE 00031 #define ATOKENBUFFER_H_GATE 00032 00033 #include "config.h" 00034 #include ATOKEN_H 00035 #include ATOKENSTREAM_H 00036 #include <stdlib.h> 00037 00038 /* 00039 * The parser is "attached" to an ANTLRTokenBuffer via interface 00040 * functions: getToken() and bufferedToken(). The object that actually 00041 * consumes characters and constructs tokens is connected to the 00042 * ANTLRTokenBuffer via interface function ANTLRTokenStream::getToken(); 00043 * where ANTLRTokenStream is really just a behavior (class with no data). 00044 * C++ does not have this abstraction and hence we simply have come up 00045 * with a fancy name for "void *". See the note in ANTLRTokenStream.h on 00046 * the "behavior" of ANTLRTokenStream. 00047 */ 00048 00049 class ANTLRParser; // MR1 00050 00051 class ANTLRTokenBuffer { 00052 protected: 00053 ANTLRTokenStream *input; // where do I get tokens 00054 int buffer_size; 00055 int chunk_size; 00056 int num_markers; 00057 int k; // Need at least this many tokens in buffer 00058 _ANTLRTokenPtr *buffer; // buffer used for arbitrary lookahead 00059 _ANTLRTokenPtr *tp; // pts into buffer; current token ptr 00060 _ANTLRTokenPtr *last; // pts to last valid token in buffer 00061 _ANTLRTokenPtr *next; // place to put token from getANTLRToken() 00062 _ANTLRTokenPtr *end_of_buffer; 00063 /* when you try to write a token past this and there are no markers 00064 set, then move k-1 tokens back to the beginning of the buffer. 00065 We want to stay away from the end of the buffer because we have 00066 to extend it if a marker is set and we reach the end (we cannot 00067 move tokens to the beginning of the buffer in this case). 00068 */ 00069 _ANTLRTokenPtr *threshold; 00070 unsigned char _deleteTokens; 00071 00072 // This function is filled in by the subclass; it initiates fetch of input 00073 virtual _ANTLRTokenPtr getANTLRToken() { return input->getToken(); } 00074 void makeRoom(); 00075 void extendBuffer(); 00076 00077 public: 00078 ANTLRTokenBuffer(ANTLRTokenStream *in, int k=1, int chksz=50); 00079 virtual ~ANTLRTokenBuffer(); 00080 virtual _ANTLRTokenPtr getToken(); 00081 virtual void rewind(int pos); 00082 virtual int mark(); 00083 virtual _ANTLRTokenPtr bufferedToken(int i); 00084 00085 void noGarbageCollectTokens() { _deleteTokens=0; } 00086 void garbageCollectTokens() { _deleteTokens=1; } 00087 00088 virtual int bufferSize() { return buffer_size; } 00089 virtual int minTokens() { return k; } 00090 virtual void setMinTokens(int k_new) { k = k_new; } 00091 00092 virtual void panic(char *msg) { exit(PCCTS_EXIT_FAILURE); } 00093 protected: // MR1 00094 ANTLRParser *parser; // MR1 00095 public: // MR1 00096 ANTLRParser *setParser(ANTLRParser *p); // MR1 00097 ANTLRParser *getParser(); // MR1 00098 ANTLRTokenStream *getLexer() const { // MR12 00099 return input;} // MR12 00100 }; 00101 00102 #endif