sqlpp11/include/sqlpp11/integral.h

/*
 * Copyright (c) 2013, Roland Bock
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 * 
 *   Redistributions of source code must retain the above copyright notice, this
 *   list of conditions and the following disclaimer.
 * 
 *   Redistributions in binary form must reproduce the above copyright notice, this
 *   list of conditions and the following disclaimer in the documentation and/or
 *   other materials provided with the distribution.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef SQLPP_INTEGRAL_H
#define SQLPP_INTEGRAL_H

#include <cstdlib>
#include <sqlpp11/basic_operators.h>
#include <sqlpp11/type_traits.h>
#include <sqlpp11/exception.h>
#include <sqlpp11/vendor/value_type.h>

namespace sqlpp
{
	namespace detail
	{

		// integral value type
		struct integral
		{
			using _base_value_type = integral;
			using _is_numeric = std::true_type;
			using _is_integral = std::true_type;
			using _is_value = std::true_type;
			using _is_expression = std::true_type;
			using _cpp_value_type = int64_t;
			
			struct _parameter_t
			{
				using _value_type = integral;

				_parameter_t():
					_value(0),
					_is_null(true)
					{}

				explicit _parameter_t(const _cpp_value_type& value):
					_value(value),
					_is_null(false)
					{}

				_parameter_t& operator=(const _cpp_value_type& value)
				{
					_value = value;
					_is_null = false;
					return *this;
				}

				void set_null()
				{
					_value = 0;
					_is_null = true;
				}

				bool is_null() const
			 	{ 
					return _is_null; 
				}

				const _cpp_value_type& value() const
				{
					return _value;
				}

				operator _cpp_value_type() const { return _value; }

				template<typename Target>
					void _bind(Target& target, size_t index) const
					{
						target._bind_integral_parameter(index, &_value, _is_null);
					}

			private:
				_cpp_value_type _value;
				bool _is_null;
			};

			template<typename Db, bool NullIsTrivial = false>
			struct _result_entry_t
			{
				using _value_type = integral;

				_result_entry_t():
					_is_valid(false),
					_is_null(true),
					_value(0)
					{}

				_result_entry_t(const char* data, size_t):
					_is_valid(true),
					_is_null(data == nullptr),
					_value(_is_null ? 0 : std::strtoll(data, nullptr, 10))
					{}

				void assign(const char* data, size_t)
				{
					_is_valid = true;
					_is_null = data == nullptr;
					_value = _is_null ? 0 : std::strtoll(data, nullptr, 10);
				}

				void invalidate()
				{
					_is_valid = false;
					_is_null = true;
					_value = 0;
				}

				void validate()
				{
					_is_valid = true;
				}

				bool is_null() const
			 	{ 
					if (not _is_valid)
						throw exception("accessing is_null in non-existing row");
					return _is_null; 
				}

				_cpp_value_type value() const
				{
					if (not _is_valid)
						throw exception("accessing value in non-existing row");
					return _value;
				}

				operator _cpp_value_type() const { return value(); }

				template<typename Target>
					void _bind(Target& target, size_t i)
					{
						target._bind_integral_result(i, &_value, &_is_null);
					}

			private:
				bool _is_valid;
				bool _is_null;
				_cpp_value_type _value;
			};

			template<typename T>
				using _operand_t = operand_t<T, is_numeric_t>;
			template<typename T>
				using _constraint = is_numeric_t<T>;

			template<typename Base>
				struct operators: public basic_operators<Base, _operand_t>
			{
				template<typename T>
					vendor::plus_t<Base, vendor::value_type_t<T>, typename _operand_t<T>::type> operator +(T t) const
					{
						static_assert(not is_multi_expression_t<Base>::value, "multi-expression cannot be used as left hand side operand");
						return { *static_cast<const Base*>(this), {t} };
					}

				template<typename T>
					vendor::minus_t<Base, vendor::value_type_t<T>, typename _operand_t<T>::type> operator -(T t) const
					{
						static_assert(not is_multi_expression_t<Base>::value, "multi-expression cannot be used as left hand side operand");
						return { *static_cast<const Base*>(this), {t} };
					}

				template<typename T>
					vendor::multiplies_t<Base, vendor::value_type_t<T>, typename _operand_t<T>::type> operator *(T t) const
					{
						static_assert(not is_multi_expression_t<Base>::value, "multi-expression cannot be used as left hand side operand");
						return { *static_cast<const Base*>(this), {t} };
					}

				template<typename T>
					vendor::divides_t<Base, typename _operand_t<T>::type> operator /(T t) const
					{
						static_assert(not is_multi_expression_t<Base>::value, "multi-expression cannot be used as left hand side operand");
						return { *static_cast<const Base*>(this), {t} };
					}

				template<typename T>
					vendor::modulus_t<Base, typename _operand_t<T>::type> operator %(T t) const
					{
						static_assert(not is_multi_expression_t<Base>::value, "multi-expression cannot be used as left hand side operand");
						return { *static_cast<const Base*>(this), {t} };
					}

				vendor::unary_plus_t<integral, Base> operator +() const
				{
					static_assert(not is_multi_expression_t<Base>::value, "multi-expression cannot be used as unary operand");
					return { *static_cast<const Base*>(this) };
				}

				vendor::unary_minus_t<integral, Base> operator -() const
				{
					static_assert(not is_multi_expression_t<Base>::value, "multi-expression cannot be used as unary operand");
					return { *static_cast<const Base*>(this) };
				}

				template<typename T>
					auto operator +=(T t) const -> decltype(std::declval<Base>() = std::declval<Base>() + t)
					{
						return *static_cast<const Base*>(this) = operator +(t);
					}

				template<typename T>
					auto operator -=(T t) const -> decltype(std::declval<Base>() = std::declval<Base>() - t)
					{
						return *static_cast<const Base*>(this) = operator -(t);
					}

				template<typename T>
					auto operator /=(T t) const -> decltype(std::declval<Base>() = std::declval<Base>() / t)
					{
						return *static_cast<const Base*>(this) = operator /(t);
					}

				template<typename T>
					auto operator *=(T t) const -> decltype(std::declval<Base>() = std::declval<Base>() * t)
					{
						return *static_cast<const Base*>(this) = operator *(t);
					}


			};
		};

		template<typename Db, bool NullIsTrivial>
		inline std::ostream& operator<<(std::ostream& os, const integral::_result_entry_t<Db, NullIsTrivial>& e)
		{
			return os << e.value();
		}
	}

	using tinyint = detail::integral;
	using smallint = detail::integral;
	using integer = detail::integral;
	using bigint = detail::integral;

}
#endif