mapnik/include/mapnik/value.hpp
2009-01-10 11:42:17 +00:00

654 lines
16 KiB
C++

/*****************************************************************************
*
* This file is part of Mapnik (c++ mapping toolkit)
*
* Copyright (C) 2006 Artem Pavlenko
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
*****************************************************************************/
//$Id$
#ifndef VALUE_HPP
#define VALUE_HPP
// mapnik
#include <mapnik/unicode.hpp>
#include <mapnik/config_error.hpp>
// boost
#include <boost/variant.hpp>
#include <boost/scoped_array.hpp>
#include <boost/concept_check.hpp>
// stl
#include <iostream>
#include <string>
#include <sstream>
#include <iomanip>
// uci
#include <unicode/unistr.h>
#include <unicode/ustring.h>
namespace mapnik {
inline void to_utf8(UnicodeString const& input, std::string & target)
{
if (input.length() == 0) return;
const int BUF_SIZE = 256;
char buf [BUF_SIZE];
int len;
UErrorCode err = U_ZERO_ERROR;
u_strToUTF8(buf, BUF_SIZE, &len, input.getBuffer(), input.length(), &err);
if (err == U_BUFFER_OVERFLOW_ERROR || err == U_STRING_NOT_TERMINATED_WARNING )
{
boost::scoped_array<char> buf_ptr(new char [len+1]);
err = U_ZERO_ERROR;
u_strToUTF8(buf_ptr.get() , len + 1, &len, input.getBuffer(), input.length(), &err);
target.assign(buf_ptr.get() , len);
}
else
{
target.assign(buf, len);
}
}
struct value_null
{
};
typedef boost::variant<value_null,bool,int,double,UnicodeString> 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() (UnicodeString const& lhs,
UnicodeString const& rhs) const
{
return lhs == rhs;
}
bool operator() (value_null, value_null) const
{
return false;
}
};
struct not_equals
: public boost::static_visitor<bool>
{
template <typename T, typename U>
bool operator() (const T &, const U &) const
{
return true;
}
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() (UnicodeString const& lhs,
UnicodeString const& rhs) const
{
return lhs != rhs;
}
bool operator() (value_null, value_null) const
{
return false;
}
template <typename T>
bool operator() (value_null, const T &) const
{
return false;
}
template <typename T>
bool operator() (const T &, value_null) const
{
return false;
}
};
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() (UnicodeString const& lhs, UnicodeString const& rhs) const
{
return lhs > rhs;
}
bool operator() (value_null, value_null) const
{
return false;
}
};
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() (UnicodeString const& lhs, UnicodeString const& rhs) const
{
return lhs >= rhs;
}
bool operator() (value_null, value_null) const
{
return false;
}
};
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()(UnicodeString const& lhs,
UnicodeString const& rhs ) const
{
return lhs < rhs;
}
bool operator() (value_null, value_null) const
{
return false;
}
};
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()(UnicodeString const& lhs,
UnicodeString const& rhs ) const
{
return lhs <= rhs;
}
bool operator() (value_null, value_null) const
{
return false;
}
};
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() (UnicodeString const& lhs ,
UnicodeString 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() (UnicodeString const& lhs,
UnicodeString 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() (UnicodeString const& lhs,
UnicodeString 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() (UnicodeString const& lhs,
UnicodeString 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_bool : public boost::static_visitor<bool>
{
template <typename T>
bool operator() (T val) const
{
boost::ignore_unused_variable_warning(val);
throw config_error("Boolean value expected");
}
bool operator() (bool val) const
{
return val;
}
};
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();
}
// specializations
std::string operator() (UnicodeString const& val) const
{
std::string utf8;
to_utf8(val,utf8);
return utf8;
}
std::string operator() (double val) const
{
std::stringstream ss;
ss << std::setprecision(16) << val;
return ss.str();
}
std::string operator() (value_null const& val) const
{
boost::ignore_unused_variable_warning(val);
return "";
}
};
struct to_unicode : public boost::static_visitor<UnicodeString>
{
template <typename T>
UnicodeString operator() (T val) const
{
std::basic_ostringstream<char> out;
out << val;
return UnicodeString(out.str().c_str());
}
// specializations
UnicodeString const& operator() (UnicodeString const& val) const
{
return val;
}
UnicodeString operator() (double val) const
{
std::basic_ostringstream<char> out;
out << std::setprecision(16) << val;
return UnicodeString(out.str().c_str());
}
UnicodeString operator() (value_null const& val) const
{
boost::ignore_unused_variable_warning(val);
return UnicodeString("");
}
};
struct to_expression_string : public boost::static_visitor<std::string>
{
std::string operator() (UnicodeString const& val) const
{
std::string utf8;
to_utf8(val,utf8);
return "'" + utf8 + "'";
}
template <typename T>
std::string operator() (T val) const
{
std::stringstream ss;
ss << val;
return ss.str();
}
std::string operator() (double val) const
{
std::stringstream ss;
ss << std::setprecision(16) << val;
return ss.str();
}
std::string operator() (value_null const& val) const
{
boost::ignore_unused_variable_warning(val);
return "null";
}
};
}
class value
{
value_base base_;
friend const value operator+(value const&,value const&);
friend const value operator-(value const&,value const&);
friend const value operator*(value const&,value const&);
friend const value operator/(value const&,value const&);
public:
value ()
: base_(value_null()) {}
template <typename T> value(T _val_)
: base_(_val_) {}
bool operator==(value const& other) const
{
return boost::apply_visitor(impl::equals(),base_,other.base_);
}
bool operator!=(value const& other) const
{
return boost::apply_visitor(impl::not_equals(),base_,other.base_);
}
bool operator>(value const& other) const
{
return boost::apply_visitor(impl::greater_than(),base_,other.base_);
}
bool operator>=(value const& other) const
{
return boost::apply_visitor(impl::greater_or_equal(),base_,other.base_);
}
bool operator<(value const& other) const
{
return boost::apply_visitor(impl::less_than(),base_,other.base_);
}
bool operator<=(value const& other) const
{
return boost::apply_visitor(impl::less_or_equal(),base_,other.base_);
}
value_base const& base() const
{
return base_;
}
bool to_bool() const
{
return boost::apply_visitor(impl::to_bool(),base_);
}
std::string to_expression_string() const
{
return boost::apply_visitor(impl::to_expression_string(),base_);
}
std::string to_string() const
{
return boost::apply_visitor(impl::to_string(),base_);
}
UnicodeString to_unicode() const
{
return boost::apply_visitor(impl::to_unicode(),base_);
}
};
inline const value operator+(value const& p1,value const& p2)
{
return value(boost::apply_visitor(impl::add<value>(),p1.base_, p2.base_));
}
inline const value operator-(value const& p1,value const& p2)
{
return value(boost::apply_visitor(impl::sub<value>(),p1.base_, p2.base_));
}
inline const value operator*(value const& p1,value const& p2)
{
return value(boost::apply_visitor(impl::mult<value>(),p1.base_, p2.base_));
}
inline const value operator/(value const& p1,value const& p2)
{
return value(boost::apply_visitor(impl::div<value>(),p1.base_, p2.base_));
}
template <typename charT, typename traits>
inline std::basic_ostream<charT,traits>&
operator << (std::basic_ostream<charT,traits>& out,
value const& v)
{
out << v.to_string();
return out;
}
}
#endif //VALUE_HPP