source: XMLIO_V2/external/include/Poco/Token.h @ 80

//
// Token.h
//
// $Id: //poco/1.3/Foundation/include/Poco/Token.h#1 $
//
// Library: Foundation
// Package: Streams
// Module:  StreamTokenizer
//
// Definition of the Token class.
//
// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// Permission is hereby granted, free of charge, to any person or organization
// obtaining a copy of the software and accompanying documentation covered by
// this license (the "Software") to use, reproduce, display, distribute,
// execute, and transmit the Software, and to prepare derivative works of the
// Software, and to permit third-parties to whom the Software is furnished to
// do so, all subject to the following:
// 
// The copyright notices in the Software and this entire statement, including
// the above license grant, this restriction and the following disclaimer,
// must be included in all copies of the Software, in whole or in part, and
// all derivative works of the Software, unless such copies or derivative
// works are solely in the form of machine-executable object code generated by
// a source language processor.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
// SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
// FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
//


#ifndef Foundation_Token_INCLUDED
#define Foundation_Token_INCLUDED


#include "Poco/Foundation.h"
#include <istream>


namespace Poco {


class Foundation_API Token
        /// The base class for all token classes that can be
        /// registered with the StreamTokenizer.
{
public:
        enum Class
        {
                IDENTIFIER_TOKEN,
                KEYWORD_TOKEN,
                SEPARATOR_TOKEN,
                OPERATOR_TOKEN,
                STRING_LITERAL_TOKEN,
                CHAR_LITERAL_TOKEN,
                INTEGER_LITERAL_TOKEN,
                LONG_INTEGER_LITERAL_TOKEN,
                FLOAT_LITERAL_TOKEN,
                DOUBLE_LITERAL_TOKEN,
                COMMENT_TOKEN,
                SPECIAL_COMMENT_TOKEN,
                PREPROCESSOR_TOKEN,
                WHITESPACE_TOKEN,
                EOF_TOKEN,
                INVALID_TOKEN,
                USER_TOKEN
        };
        
        Token();
                /// Creates the Token.

        virtual ~Token();
                /// Destroys the Token.
                
        virtual bool start(char c, std::istream& istr);
                /// Checks if the given character (and, optionally,
                /// the next character in the input stream) start
                /// a valid token. Returns true if so, false
                /// otherwise.
                ///
                /// The current read position in istr must not be
                /// changed. In other words, only the peek() method
                /// of istream may be used.
                ///
                /// If the character starts the token, it should
                /// be set as the token's value.

        virtual void finish(std::istream& istr);
                /// Builds the token by reading and appending 
                /// the remaining characters from istr.
                
        virtual Class tokenClass() const;
                /// Returns the kind of the token.
        
        const std::string& tokenString() const;
                /// Returns the token's raw string.
        
        virtual std::string asString() const;
                /// Returns a string representation of the token.
        
        virtual int asInteger() const;
                /// Returns an integer representation of the token.
        
        virtual double asFloat() const;
                /// Returns a floating-point representation of the token.

        virtual char asChar() const;
                /// Returns a char representation of the token.

        bool is(Class tokenClass) const;
                /// Returns true iff the token has the given class.

protected:
        std::string _value;
        
private:
        Token(const Token&);
        Token& operator = (const Token&);
};


class Foundation_API InvalidToken: public Token
        /// This token class is used for signalling that
        /// an invalid character sequence has been encountered
        /// in the input stream.
{
public:
        InvalidToken();
        ~InvalidToken();
        Class tokenClass() const;
};


class Foundation_API EOFToken: public Token
        /// This token class is used to signal the
        /// end of the input stream.
{
public:
        EOFToken();
        ~EOFToken();
        Class tokenClass() const;
};


class Foundation_API WhitespaceToken: public Token
        /// This pseudo token class is used to eat
        /// up whitespace in between real tokens.
{
public:
        WhitespaceToken();
        ~WhitespaceToken();
        Class tokenClass() const;
        bool start(char c, std::istream& istr);
        void finish(std::istream& istr);
};


//
// inlines
//
inline const std::string& Token::tokenString() const
{
        return _value;
}


inline bool Token::is(Token::Class cls) const
{
        return tokenClass() == cls;
}


} // namespace Poco


#endif // Foundation_Token_INCLUDED