valueTupleSet.hpp

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#ifndef _DATABASE_VIRTUAL_MACHINE_VALUE_TYPLE_SET_HPP_INCLUDED
#define _DATABASE_VIRTUAL_MACHINE_VALUE_TYPLE_SET_HPP_INCLUDED
#include "types/variant.hpp"
#include <string>
#include <vector>
#include <cstdlib>
#include <boost/shared_ptr.hpp>
#include <boost/algorithm/string.hpp>

namespace _Wolframe {
namespace db {
namespace vm {

class ValueTupleSet
{
public:
        ValueTupleSet(){}
        explicit ValueTupleSet( const std::vector<std::string>& colnames_)
                :m_colnames(colnames_){}
        ValueTupleSet( const ValueTupleSet& o)
                :m_colnames(o.m_colnames),m_ar(o.m_ar){}

        friend class const_iterator;

        class const_iterator
        {
        public:
                const_iterator()
                        :m_idx(0)
                {
                        static const ValueTupleSet v; 
                        m_ref = &v;
                }
                explicit const_iterator( const ValueTupleSet* ref_, std::size_t idx_=0)
                        :m_idx(idx_),m_ref(ref_){}
                const_iterator( const const_iterator& o)
                        :m_idx(o.m_idx),m_ref(o.m_ref){}
                const_iterator& operator++()
                {
                        if (m_ref)
                        {
                                m_idx += m_ref->m_colnames.size();
                        }
                        return *this;
                }
                const_iterator operator++(int)
                {
                        const_iterator rt(*this);
                        operator++();
                        return rt;
                }

                std::size_t index() const
                {
                        return m_idx;
                }

                bool operator==( const const_iterator& o) const
                {
                        return (m_ref == o.m_ref && m_idx == o.m_idx);
                }
                bool operator!=( const const_iterator& o) const
                {
                        return (m_ref != o.m_ref || m_idx != o.m_idx);
                }

                const const_iterator* operator->() const                {return this;}
                const types::Variant& column( std::size_t i) const
                {
                        if (!m_ref || i == 0 || i > m_ref->m_colnames.size() || m_idx + i - 1 >= m_ref->m_ar.size())
                        {
                                throw std::runtime_error("value tuple set column index out of range");
                        }
                        return m_ref->m_ar.at( m_idx + i - 1);
                }

        private:
                std::size_t m_idx;              //< index of currently visited element
                const ValueTupleSet* m_ref;     //< reference to visited set of tuples
        };

        const_iterator begin() const
        {
                return const_iterator( this);
        }
        const_iterator end() const
        {
                return const_iterator( this, m_ar.size());
        }

        std::size_t nofColumns() const
        {
                return m_colnames.size();
        }
        const std::string& columnName( std::size_t i) const
        {
                if (i == 0 || i > m_colnames.size()) throw std::runtime_error( "column index out of range");
                return m_colnames.at(i-1);
        }

        std::size_t columnIndex( const std::string& name) const
        {
                std::size_t ii=0;
                for (; ii<m_colnames.size(); ++ii)
                {
                        if (boost::algorithm::iequals( name, m_colnames.at(ii)))
                        {
                                return ii+1;
                        }
                }
                throw std::runtime_error("unknown value set column name");
        }

        void push( const std::vector<types::VariantConst>& c)
        {
                if (c.size() != m_colnames.size()) throw std::runtime_error("pushed result with non matching number of columns");
                for (std::vector<types::VariantConst>::const_iterator ci=c.begin(), ce=c.end(); ci != ce; ++ci)
                {
                        m_ar.push_back( *ci);
                }
        }

        void push( const std::vector<types::Variant>& c)
        {
                if (c.size() != m_colnames.size()) throw std::runtime_error("pushed result with non matching number of columns");
                for (std::vector<types::Variant>::const_iterator ci=c.begin(), ce=c.end(); ci != ce; ++ci)
                {
                        m_ar.push_back( *ci);
                }
        }

        std::size_t size() const        
        {
                return m_ar.size() / m_colnames.size();
        }

        bool empty() const
        {
                return m_ar.empty();
        }

        void checkConstraintNonEmpty() const
        {
                if (size() == 0) throw std::runtime_error( "constraint 'set non empty' failed");
        }

        void checkConstraintUnique() const
        {
                if (size() > 1) throw std::runtime_error( "constraint 'set unique' failed");
        }

        void append( const ValueTupleSet& ts)
        {
                if (ts.m_colnames.size() != m_colnames.size()) throw std::runtime_error("joining incompatible lists");
                m_ar.insert( m_ar.end(), ts.m_ar.begin(), ts.m_ar.end());
        }

private:
        std::vector<std::string> m_colnames;
        std::vector<types::Variant> m_ar;
};

typedef boost::shared_ptr<ValueTupleSet> ValueTupleSetR;

}}}//namespace
#endif