range_expression.h

/***************************************************************************
 *   Copyright (C) 2006 by Radko Mihal                                     *
 *   rmihal@pobox.sk                                                       *
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 *   This program is distributed in the hope that it will be useful,       *
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
 *   GNU General Public License for more details.                          *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this program; if not, write to the                         *
 *   Free Software Foundation, Inc.,                                       *
 *   51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.              *
 ***************************************************************************/
#ifndef BRACKET_EXPRESSIONRANGE_EXPRESSION_H
#define BRACKET_EXPRESSIONRANGE_EXPRESSION_H

namespace bracket_expression {

template<typename E>
class range_expression
{
typedef typename grammar_to_parser::basic_parser<E>::parser_list 
                                                                                                                                parser_list;
        
        class start_range_and_end_range
        {
                grammar_to_parser::basic_non_terminal<E,start_range<E> >        
                                                                                                                        m_start_range;
                grammar_to_parser::basic_choice<E,collating_choice<E> >
                                                                                                                        m_end_range;
                
        public:
                unsigned long recognize( const E* buf, const unsigned long buf_length )
                {
                        int start_ret = m_start_range->compare(buf,buf_length);
                        int size = m_start_range->matched_size();
                        while( start_ret < 0 && size > 1) 
                        {
                                size--;
                                // while the buf is not higher as start range, try smaller -
                                // collating symbol in buffer
                                start_ret = m_start_range->compare(buf,size);
                        }
                        int end_ret = 0;
                        if( start_ret > 0 )
                        {
                                end_ret = m_end_range->compare(buf,size);
                                while( end_ret > 0 && 
                                                size > 1 && 
                                                m_start_range->compare(buf,size-1) >= 0 )
                                {
                                        size--;
                                        end_ret = m_end_range->compare(buf,size);
                                }
                        }
                        if( start_ret >=0 && end_ret <= 0 )
                                return size;
                        else
                                return 0;
                }
                
                start_range_and_end_range() : m_start_range() {};
                ~start_range_and_end_range() {};
                void push_parsers( parser_list &l )
                {
                        l.push_back( &m_start_range );
                        l.push_back( &m_end_range );
                }       
        };
        
        class start_range_and_hyphen
        {
                grammar_to_parser::basic_non_terminal<E,start_range<E> >        
                                                                                                                                m_start_range;
                grammar_to_parser::basic_terminal<E,'-'>                                m_hyphen;
                
        public:
                unsigned long recognize( const E* buf, const unsigned long buf_length )
                {
                        int start_ret = m_start_range->compare(buf,buf_length);
                        int size = m_start_range->matched_size();
                        while( start_ret < 0 && size > 1) 
                        {
                                size--;
                                // while the buf is not higher as start range, try smaller -
                                // collating symbol in buffer
                                start_ret = m_start_range->compare(buf,size);
                        }
                        int end_ret = 0;
                        if( start_ret > 0 )
                        {
                                end_ret = std::use_facet< std::collate<E> >(std::locale()).compare(
                                                                                                buf,
                                                                                                buf+size,
                                                                                                m_hyphen.get(),
                                                                                                m_hyphen.get()+1 );
                                while( end_ret > 0 && 
                                                size > 1 && 
                                                m_start_range->compare(buf,size-1) >= 0 )
                                {
                                        size--;
                                        end_ret = std::use_facet< std::collate<E> >(std::locale()).compare(
                                                                                                buf,
                                                                                                buf+size,
                                                                                                m_hyphen.get(),
                                                                                                m_hyphen.get()+1 );
                                }
                        }
                        if( start_ret >=0 && end_ret <= 0 )
                                return size;
                        else
                                return 0;
                }
                
                start_range_and_hyphen() : m_start_range() {};
                ~start_range_and_hyphen() {};
                void push_parsers( parser_list &l )
                {
                        l.push_back( &m_start_range );
                        l.push_back( &m_hyphen );
                }       
        };      
        
        grammar_to_parser::basic_non_terminal<E,start_range_and_end_range >     
                                                                                                                m_start_end_range;
        grammar_to_parser::basic_non_terminal<E,start_range_and_hyphen >                
                                                                                                                m_start_and_hyphen;
        
public:
        unsigned long recognize( const E* buf, const unsigned long buf_length )
        {
                if( m_start_end_range.is_parsed() )
                {
                        return m_start_end_range->recognize(buf,buf_length);
                }
                else
                {
                        return m_start_and_hyphen->recognize(buf,buf_length);
                }
        }
    range_expression() : m_start_end_range(), m_start_and_hyphen() {};

    ~range_expression() {};
        void push_parsers( parser_list &l )
        {
                l.push_back( &m_start_end_range );
                l.push_back( &m_start_and_hyphen );
        }       

};

};

#endif

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