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      1 // Copyright 2016 The SwiftShader Authors. All Rights Reserved.
      2 //
      3 // Licensed under the Apache License, Version 2.0 (the "License");
      4 // you may not use this file except in compliance with the License.
      5 // You may obtain a copy of the License at
      6 //
      7 //    http://www.apache.org/licenses/LICENSE-2.0
      8 //
      9 // Unless required by applicable law or agreed to in writing, software
     10 // distributed under the License is distributed on an "AS IS" BASIS,
     11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     12 // See the License for the specific language governing permissions and
     13 // limitations under the License.
     14 
     15 #ifndef COMPILER_PREPROCESSOR_MACRO_EXPANDER_H_
     16 #define COMPILER_PREPROCESSOR_MACRO_EXPANDER_H_
     17 
     18 #include <cassert>
     19 #include <memory>
     20 #include <vector>
     21 
     22 #include "Lexer.h"
     23 #include "Macro.h"
     24 #include "pp_utils.h"
     25 
     26 namespace pp
     27 {
     28 
     29 class Diagnostics;
     30 
     31 class MacroExpander : public Lexer
     32 {
     33 public:
     34 	MacroExpander(Lexer* lexer, MacroSet* macroSet, Diagnostics* diagnostics, bool parseDefined);
     35 	virtual ~MacroExpander();
     36 
     37 	virtual void lex(Token* token);
     38 
     39 private:
     40 	PP_DISALLOW_COPY_AND_ASSIGN(MacroExpander);
     41 
     42 	void getToken(Token* token);
     43 	void ungetToken(const Token& token);
     44 	bool isNextTokenLeftParen();
     45 
     46 	bool pushMacro(const Macro& macro, const Token& identifier);
     47 	void popMacro();
     48 
     49 	bool expandMacro(const Macro& macro,
     50 	                 const Token& identifier,
     51 	                 std::vector<Token>* replacements);
     52 
     53 	typedef std::vector<Token> MacroArg;
     54 	bool collectMacroArgs(const Macro& macro,
     55 	                      const Token& identifier,
     56 	                      std::vector<MacroArg>* args);
     57 	void replaceMacroParams(const Macro& macro,
     58 	                        const std::vector<MacroArg>& args,
     59 	                        std::vector<Token>* replacements);
     60 
     61 	struct MacroContext
     62 	{
     63 		const Macro* macro;
     64 		size_t index;
     65 		std::vector<Token> replacements;
     66 
     67 		MacroContext() : macro(0), index(0) { }
     68 		bool empty() const { return index == replacements.size(); }
     69 		const Token& get() { return replacements[index++]; }
     70 		void unget() { assert(index > 0); --index; }
     71 	};
     72 
     73 	Lexer* mLexer;
     74 	MacroSet* mMacroSet;
     75 	Diagnostics* mDiagnostics;
     76 	const bool mParseDefined;
     77 
     78 	std::auto_ptr<Token> mReserveToken;
     79 	std::vector<MacroContext*> mContextStack;
     80 };
     81 
     82 }  // namespace pp
     83 #endif  // COMPILER_PREPROCESSOR_MACRO_EXPANDER_H_
     84 
     85