/*

* Copyright (c) 2010 Nokia Corporation and/or its subsidiary(-ies).

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of "Eclipse Public License v1.0"

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

*

* Description: 

*

*/

/*

 * cpixparsetools.h

 *

 *  Created on: Apr 14, 2009

 *      Author: admin

 */

#ifndef CPIXPARSETOOLS_H_

#define CPIXPARSETOOLS_H_

#include <string>

#include <wchar.h>

#include <ctype.h>

#include <exception>

#include <vector>

#include <memory>

namespace Cpt {

    /**

     * Exception class that can gather some contextual information as

     * it ascends in the call stack.

     */

    class ITxtCtxtExc

    {

    public:

        /**

         * TODO comment

         */

        virtual const wchar_t * wWhat() const throw () = 0;

        /**

         * TODO comment: after an invocation of setContext, the string

         * returned by wWhat() should be far more informative.

         */

        virtual void setContext(const wchar_t * context) = 0;

        /**

         * TODO comment and move to .cpp file

         */

        virtual ~ITxtCtxtExc() { ; }

    };

    /**

     * Tools for lexical analysis, that is parsing regular expression

     * strength language and converting the character stream into

     * language token stream.  Note: Regular expression syntax

     * (e.g. "file*.tx?") itself is not supported)

     */

    namespace Lex {

        class LexException : public ITxtCtxtExc {

        public: 

            LexException(const wchar_t* what, const wchar_t* where);

            virtual ~LexException(); 

            const wchar_t * where() const;

            virtual const wchar_t * wWhat() const throw ();

            virtual void setContext(const wchar_t * context);

        private:

            std::wstring wWhat_; 

            const wchar_t* where_;

        };

        /**

         * A token provided by regular expression. Contains pointers

         * into the original data string. NOTE: this object becomes

         * hazardous, if the original tokenized string is modified or

         * released.

         */

        class Token {

        public: 

            Token();

            const wchar_t* begin() const;

            const wchar_t* end() const;

            int length() const;

            std::wstring text() const; 

        private: 

            const wchar_t* begin_;

            const wchar_t* end_;

        };

        /**

         * Describes the state of the tokenizer. 

         */

        enum TokenizerState { 

            TOKENIZER_HUNGRY, 	/// ok, but don't have yet a proper token formed.

            TOKENIZER_FINISHED, /// has ready token

            TOKENIZER_FAILED 	/// failed

        };

        /**

         * Provides mechanism for extracting nearly regular expression

         * strength tokens.

         */

        class Tokenizer {

        public: 

            virtual ~Tokenizer(); 

            /**

             * Prepares the tokenizer for consuming a new token.

             */

            virtual void reset() = 0;

            /**

             * Returns the token. MUST be called only, if tokenizer

             * has returned TOKENIZER_FINISHED with last call to

             * consume and reset has not been called.

             */

            virtual Token get() = 0; 

            /**

             * Consumes a character and returns the state of the

             * tokenizer. If the tokenizer returns TOKENIZER_FINISHED,

             * the read token can be requested by using get().

             */

            virtual TokenizerState consume(const wchar_t* cursor) = 0; 

        };

        class StrLitTokenizer : public Tokenizer {

        public: 

            StrLitTokenizer(wchar_t citate); 

            virtual void reset();

            virtual Token get(); 

            virtual TokenizerState consume(const wchar_t* cursor);

        private:

            const wchar_t* begin_; 

            const wchar_t* end_; 

            wchar_t citate_;

            bool opened_; 

            bool escape_;

        };

        class IntLitTokenizer : public Tokenizer {

        public:

            IntLitTokenizer();

            virtual void reset();

            virtual Token get();

            virtual TokenizerState consume(const wchar_t * cursor);

        private:

            const wchar_t * begin_;

            const wchar_t * end_;

            bool            beginning_;

        };

        class RealLitTokenizer : public Tokenizer {

        public:

            RealLitTokenizer();

            virtual void reset();

            virtual Token get();

            virtual TokenizerState consume(const wchar_t * cursor);

        private:

            const wchar_t * begin_;

            const wchar_t * end_;

            bool            beginning_;

            bool            hadDotAlready_;

        };

        class WhitespaceTokenizer : public Tokenizer {

        public: 

            WhitespaceTokenizer();

            virtual void reset();

            virtual Token get();

            virtual TokenizerState consume(const wchar_t* cursor);

        private:

            const wchar_t* begin_; 

            const wchar_t* end_; 

            bool empty_;

        };

        class IdTokenizer : public Tokenizer {

        public: 

            IdTokenizer(); 

            virtual void reset();

            virtual Token get();

            virtual TokenizerState consume(const wchar_t* cursor);

        private:

            const wchar_t* begin_; 

            const wchar_t* end_; 

        };

        class SymbolTokenizer : public Tokenizer {

        public: 

            virtual void reset();

            virtual Token get();

            virtual TokenizerState consume(const wchar_t* cursor);

        private:

            const wchar_t* begin_;

            const wchar_t* end_; 

            const wchar_t* symbol_;

        };

        /**

         * Tokenizes text by using given tokenizers. Text is consumed

         * until no tokenizer is in hungry state e.g., all tokenizers

         * are either failed or finished. In case a number of

         * tokenizers have finished, the longest token is used. If a

         * number of tokens have the same length, the order is

         * determined based on order of the tokenizers array. The

         * tokenizers first in the list have highest priority.

         */

        class MultiTokenizer : public Tokenizer {

        public: 

            /**

             * @param tokenizers zero-terminated array. Nothing passes

             * ownership. The array itself need not be alive later,

             * but the contained tokenizers do.

             */

            MultiTokenizer(Tokenizer** tokenizers, bool ownTokenizers = false);

            virtual ~MultiTokenizer(); 

            void reset();

            Token get();

            TokenizerState consume(const wchar_t* cursor);

        private:

            int running_;

            bool found_; 

            TokenizerState* states_;

            std::vector<Tokenizer*> tokenizers_;

            bool ownTokenizers_;

        };

        /**

         * Tokenizes whatever literals: string, real or int. The token

         * type of the tokens returned by this class are TOKEN_LIT

         * (you don't know if they are str, int or real).

         */

        class LitTokenizer : public Tokenizer {

        public:

            /**

             * Strings literals will be tokenized according to citate

             * (see StrLitTokenizer constructor).

             */

            LitTokenizer(wchar_t citate);

            virtual ~LitTokenizer();

            virtual void reset();

            virtual Token get();

            virtual TokenizerState consume(const wchar_t * cursor);

        private:

            MultiTokenizer   * multiTokenizer_;

        };

        /**

         * Not-so-C++ style iterator for iterating through tokens.

         * When having a variable i of type TokenIterator, check if

         * (i) can be used to see

         */

        class TokenIterator {

        public:

            /**

             * Returns true, if token iterator contains more tokens

             */

            virtual operator bool() = 0;

            /**

             * Returns the next token in the stream.  FIXME should be

             * operator of form ++i. Current syntax breaks C++

             * standard

             */

            virtual Token operator++(int) = 0;

            virtual ~TokenIterator(); 

        };

        /**

         * Uses tokenizer for converting given text into token stream

         * and provides means for iterating throught the token

         * stream's tokens.

         */

        class Tokens : public TokenIterator {

        public:

            Tokens(Tokenizer& tokenizer, const wchar_t* text);

            virtual operator bool();

            virtual Token operator++(int);

        private:

            void prepareNext();

        private: // data

            /**

             * Current location in the text

             */

            const wchar_t* cursor_; 

            Tokenizer& tokenizer_;

            bool hasNext_; 

        };

        /**

         * Filters out all tokens of type TOKEN_WS

         */

        public:

            virtual operator bool();

            virtual Token operator++(int);

        private:

            void prepareNext();

        private: // data

            TokenIterator& tokens_; 

            Token next_;  

            bool hasNext_;

        };

        /**

         * Provides mechanism for marking a location in the token

         * stream and returning to it. Essential tool for parsing

         * context free grammar.

         */

        class TokenReader : public TokenIterator {

        public: 

            TokenReader(TokenIterator& tokens); 

            virtual operator bool();

            virtual Token operator++(int);

            Token peek(); 

            void pushMark();   // stores this position

            void popMark();    // pops position and returns reader to point it

            void clearMark();  // pops position and frees it; may also free tokens in backward buf.

        private: 

            TokenIterator& tokens_;

            int location_;

            std::vector<Token> forward_; // buffer for tokens front of this location

            std::vector<Token> backward_; // buffer for tokens behind this location

            std::vector<int> marks_; 

        };

        /**

         * Marks the position in the token stream and returns the

         * token stream position, when going out of scope unless

         * release is called.

         */

        class TokenPositionSentry {

        public:

            inline TokenPositionSentry(TokenReader& reader) 

                : reader_(reader), released_(false) { 

                reader_.pushMark(); 

            }

            inline ~TokenPositionSentry() {

                if (released_) {

                    reader_.clearMark(); 

                } else {

                    reader_.popMark(); 

                }

            }

            inline void release() { released_ = true; } 

        private:

            bool released_; 

            TokenReader& reader_; 

        };

    } // Lex 

    /**

     * Tools for parsing context-free grammar

     */

    namespace Parser {

        /**

         * Informs of an parsing error. 

         */

        class ParseException : public ITxtCtxtExc {

        public: 

            ParseException(const wchar_t* wWhat, const Lex::Token& where);

            Lex::Token where() const; 

            virtual const wchar_t * wWhat() const throw ();

            virtual void setContext(const wchar_t * context);

        private:

            std::wstring wWhat_; 

            Lex::Token where_;

        };

        namespace Lit {

            std::wstring ParseString(const Lex::Token& token) ;  

            long ParseInteger(const Lex::Token& token);

            double ParseReal(const Lex::Token& token);

        }

        /**

         * Utility, which is used for parsing. Throws parse

         * exceptions, when underlying assumptions don't hold.

         */

        class Lexer : public Lex::TokenReader {

        public: 

            Lexer(Lex::TokenIterator& tokens); 

            // throws ParseException instead of LexException on EOF. 

            virtual Lex::Token operator++(int);

            void eatEof();

            std::wstring eatId();

            std::wstring eatString();

            long eatInteger();

            double eatReal();

        };

        /*

         * Creates token stream iterator and whitespace filter

         */ 

        class StdLexer : public Lexer {

        public: 

            StdLexer(Lex::Tokenizer& tokens, const wchar_t* text); 

        private: 

            Lex::Tokens tokens_; 

        };

    } // Parser

} // Cpt

#endif /* CPIXPARSETOOLS_H_ */