pgLab/pgsql/Pgsql_Value.h

#ifndef PGSQL_VALUE_H
#define PGSQL_VALUE_H

#include "Pgsql_declare.h"
#include "ArrayParser.h"
#include <sstream>
#include <QString>
#include <QDateTime>

namespace Pgsql {


	/** \brief Class that is returned as value of a cell to facilitate auto conversion.
	 */
	class Value {
	public:
		Value(const char *val, Oid typ);
		QString asQString() const;
		const char* c_str() const { return m_val; }

		operator QString() const;
		operator QDateTime() const;
		operator QDate() const;
		operator QTime() const;
		operator std::string() const;
		operator int16_t() const;
		operator int32_t() const;
		operator Oid() const;
		operator int64_t() const;
		operator bool() const;
		operator float() const;
		operator double() const;

		bool isString() const;

		enum class NullHandling {
			Ignore,
			Throw
		};
		/**
		 *
		 * \param insert_iter An insert_iterator which is used to add the elements of the array to a container.
		 */
		template <typename E, typename I>
		void getAsArray(I insert_iter, NullHandling nullhandling = NullHandling::Throw) const
		{
			using value_type = E;
			ArrayParser parser(m_val);
			for (;;) {
				auto res = parser.GetNextElem();
				if (res.ok) {
					if (res.value) {
						std::string str(res.value->data(), res.value->length());
						Value val(str.c_str(), ANYOID);
						value_type v;
						v << val;
						insert_iter = v;
					}
					else {
						if (nullhandling == NullHandling::Throw)
							throw std::runtime_error("Unexpected NULL value in array");
					}
				}
				else
					break;
			}
		}

		template <typename E, typename I>
		void getAsArray(I insert_iter, const E &value_for_nulls) const
		{
			using value_type = E;
			ArrayParser parser(m_val);
			for (;;) {
				auto res = parser.GetNextElem();
				if (res.ok) {
					if (res.value) {
						std::string str(res.value->data(), res.value->length());
						Value val(str.c_str(), ANYOID);
						value_type v;
						v << val;
						insert_iter = v;
					}
					else {
						insert_iter = value_for_nulls;
					}
				}
				else
					break;
			}
		}

		template <typename E, typename I>
		void getAsArrayOfOptional(I insert_iter) const
		{
			using value_type = E;
			ArrayParser parser(m_val);
			for (;;) {
				auto res = parser.GetNextElem();
				if (res.ok) {
					if (res.value) {
						std::string str(res.value->data(), res.value->length());
						Value val(str.c_str(), ANYOID);
						value_type v;
						v << val;
						insert_iter = v;
					}
					else {
						insert_iter = std::nullopt;
					}
				}
				else
					break;
			}
		}
	private:
		const char *m_val;
		Oid m_typ;
	};

	template <typename T>
	void operator<<(T &s, const Value &v)
	{
		s = static_cast<T>(v);
	}
	
	
} // end namespace Pgsql

#endif // PGSQL_VALUE_H