mapnik/include/value.hpp
2006-02-21 19:55:24 +00:00

458 lines
9.3 KiB
C++

/* This file is part of Mapnik (c++ mapping toolkit)
* Copyright (C) 2005 Artem Pavlenko
*
* Mapnik 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 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
//$Id$
#ifndef VALUE_HPP
#define VALUE_HPP
#include <string>
#include <sstream>
#include <boost/variant.hpp>
using namespace boost;
namespace mapnik {
typedef variant<int,double,std::string> value_base;
namespace impl {
struct equals
: public boost::static_visitor<bool>
{
template <typename T, typename U>
bool operator() (const T &, const U & ) const
{
return false;
}
template <typename T>
bool operator() (T lhs, T rhs) const
{
return lhs == rhs;
}
bool operator() (int lhs, double rhs) const
{
return lhs == rhs;
}
bool operator() (double lhs, int rhs) const
{
return lhs == rhs;
}
bool operator() (std::string const& lhs, std::string const& rhs) const
{
return lhs == rhs;
}
};
struct greater_than
: public boost::static_visitor<bool>
{
template <typename T, typename U>
bool operator()( const T &, const U & ) const
{
return false;
}
template <typename T>
bool operator()( T lhs, T rhs ) const
{
return lhs > rhs;
}
bool operator() (int lhs, double rhs) const
{
return lhs > rhs;
}
bool operator() (double lhs, int rhs) const
{
return lhs > rhs;
}
bool operator() (std::string const& lhs, std::string const& rhs) const
{
return lhs > rhs;
}
};
struct greater_or_equal
: public boost::static_visitor<bool>
{
template <typename T, typename U>
bool operator()( const T &, const U & ) const
{
return false;
}
template <typename T>
bool operator() (T lhs, T rhs) const
{
return lhs >= rhs;
}
bool operator() (int lhs, double rhs) const
{
return lhs >= rhs;
}
bool operator() (double lhs, int rhs) const
{
return lhs >= rhs;
}
bool operator() (std::string const& lhs, std::string const& rhs ) const
{
return lhs >= rhs;
}
};
struct less_than
: public boost::static_visitor<bool>
{
template <typename T, typename U>
bool operator()( const T &, const U & ) const
{
return false;
}
template <typename T>
bool operator()( T lhs,T rhs) const
{
return lhs < rhs;
}
bool operator() (int lhs, double rhs) const
{
return lhs < rhs;
}
bool operator() (double lhs, int rhs) const
{
return lhs < rhs;
}
bool operator()( std::string const& lhs, std::string const& rhs ) const
{
return lhs < rhs;
}
};
struct less_or_equal
: public boost::static_visitor<bool>
{
template <typename T, typename U>
bool operator()( const T &, const U & ) const
{
return false;
}
template <typename T>
bool operator()(T lhs, T rhs ) const
{
return lhs <= rhs;
}
bool operator() (int lhs, double rhs) const
{
return lhs <= rhs;
}
bool operator() (double lhs, int rhs) const
{
return lhs <= rhs;
}
template <typename T>
bool operator()( std::string const& lhs, std::string const& rhs ) const
{
return lhs <= rhs;
}
};
template <typename V>
struct add : public boost::static_visitor<V>
{
typedef V value_type;
template <typename T1, typename T2>
value_type operator() (T1 const& lhs, T2 const&) const
{
return lhs;
}
template <typename T>
value_type operator() (T lhs, T rhs) const
{
return lhs + rhs ;
}
value_type operator() (std::string const& lhs,std::string const& rhs ) const
{
return lhs + rhs;
}
value_type operator() (double lhs, int rhs) const
{
return lhs + rhs;
}
value_type operator() (int lhs, double rhs) const
{
return lhs + rhs;
}
};
template <typename V>
struct sub : public boost::static_visitor<V>
{
typedef V value_type;
template <typename T1, typename T2>
value_type operator() (T1 const& lhs, T2 const&) const
{
return lhs;
}
template <typename T>
value_type operator() (T lhs, T rhs) const
{
return lhs - rhs ;
}
value_type operator() (std::string const& lhs,std::string const& ) const
{
return lhs;
}
value_type operator() (double lhs, int rhs) const
{
return lhs - rhs;
}
value_type operator() (int lhs, double rhs) const
{
return lhs - rhs;
}
};
template <typename V>
struct mult : public boost::static_visitor<V>
{
typedef V value_type;
template <typename T1, typename T2>
value_type operator() (T1 const& lhs , T2 const& ) const
{
return lhs;
}
template <typename T>
value_type operator() (T lhs, T rhs) const
{
return lhs * rhs;
}
value_type operator() (std::string const& lhs,std::string const& ) const
{
return lhs;
}
value_type operator() (double lhs, int rhs) const
{
return lhs * rhs;
}
value_type operator() (int lhs, double rhs) const
{
return lhs * rhs;
}
};
template <typename V>
struct div: public boost::static_visitor<V>
{
typedef V value_type;
template <typename T1, typename T2>
value_type operator() (T1 const& lhs, T2 const&) const
{
return lhs;
}
template <typename T>
value_type operator() (T lhs, T rhs) const
{
return lhs / rhs;
}
value_type operator() (std::string const& lhs,std::string const&) const
{
return lhs;
}
value_type operator() (double lhs, int rhs) const
{
return lhs / rhs;
}
value_type operator() (int lhs, double rhs) const
{
return lhs / rhs;
}
};
struct to_string : public boost::static_visitor<std::string>
{
template <typename T>
std::string operator() (T val) const
{
std::stringstream ss;
ss << val;
return ss.str();
}
std::string const& operator() (std::string const& val) const
{
return val;
}
};
struct to_expression_string : public boost::static_visitor<std::string>
{
template <typename T>
std::string operator() (T val) const
{
std::stringstream ss;
ss << val;
return ss.str();
}
std::string operator() (std::string const& val) const
{
return "'" + val + "'";
}
};
}
class value : public value_base
{
public:
value ()
: value_base(0) {}
template <typename T> value(T _val_)
: value_base(_val_) {}
bool operator==(value const& other) const
{
return boost::apply_visitor(impl::equals(),*this,other);
}
bool operator!=(value const& other) const
{
return !(boost::apply_visitor(impl::equals(),*this,other));
}
bool operator>(value const& other) const
{
return boost::apply_visitor(impl::greater_than(),*this,other);
}
bool operator>=(value const& other) const
{
return boost::apply_visitor(impl::greater_or_equal(),*this,other);
}
bool operator<(value const& other) const
{
return boost::apply_visitor(impl::less_than(),*this,other);
}
bool operator<=(value const& other) const
{
return boost::apply_visitor(impl::less_or_equal(),*this,other);
}
value& operator+=(value const& other)
{
*this = boost::apply_visitor(impl::add<value>(),*this,other);
return *this;
}
value& operator-=(value const& other)
{
*this = boost::apply_visitor(impl::sub<value>(),*this,other);
return *this;
}
value& operator*=(value const& other)
{
*this = boost::apply_visitor(impl::mult<value>(),*this,other);
return *this;
}
value& operator/=(value const& other)
{
*this = boost::apply_visitor(impl::div<value>(),*this,other);
return *this;
}
std::string to_expression_string() const
{
return boost::apply_visitor(impl::to_expression_string(),*this);
}
std::string to_string() const
{
return boost::apply_visitor(impl::to_string(),*this);
}
};
inline const value operator+(value const& p1,value const& p2)
{
value tmp(p1);
tmp+=p2;
return tmp;
}
inline const value operator-(value const& p1,value const& p2)
{
value tmp(p1);
tmp-=p2;
return tmp;
}
inline const value operator*(value const& p1,value const& p2)
{
value tmp(p1);
tmp*=p2;
return tmp;
}
inline const value operator/(value const& p1,value const& p2)
{
value tmp(p1);
tmp/=p2;
return tmp;
}
//template <typename charT, typename traits>
//inline std::basic_ostream<charT,traits>&
//operator << (std::basic_ostream<charT,traits>& out,/
// value const& v)
// {
// out << v.get();
// return out;
//}
}
#endif //VALUE_HPP