Initial commit

2020-02-10 20:31:06 +01:00
commit dae1243185
11 changed files with 510 additions and 0 deletions
@@ -0,0 +1,203 @@
+#ifndef TRIBOOL_H
+#define TRIBOOL_H
+
+#include <iostream>
+
+
+namespace Utilities {
+
+class Tribool
+{
+public:
+	struct IndeterminateType
+	{
+	};
+
+	typedef bool (*IndeterminateKeywordType)(Tribool, IndeterminateType);
+
+public:
+	Tribool();
+	Tribool(bool value);
+	Tribool(const IndeterminateKeywordType& value);
+
+	explicit operator bool() const;
+	Tribool operator!() const;
+
+	Tribool operator&&(const Tribool& other) const;
+	friend Tribool operator&&(const Tribool& lhs, bool rhs);
+	friend Tribool operator&&(bool lhs, const Tribool& rhs);
+	friend Tribool operator&&(const IndeterminateKeywordType& lhs, const Tribool& rhs);
+	friend Tribool operator&&(const Tribool& lhs, const IndeterminateKeywordType& rhs);
+
+	Tribool operator||(const Tribool& other) const;
+	friend Tribool operator||(const Tribool& lhs, bool rhs);
+	friend Tribool operator||(bool lhs, const Tribool& rhs);
+	friend Tribool operator||(const IndeterminateKeywordType& lhs, const Tribool& rhs);
+	friend Tribool operator||(const Tribool& lhs, const IndeterminateKeywordType& rhs);
+
+	Tribool operator==(const Tribool& other) const;
+	friend Tribool operator==(const Tribool& lhs, bool rhs);
+	friend Tribool operator==(bool lhs, const Tribool& rhs);
+	friend Tribool operator==(const IndeterminateKeywordType& lhs, const Tribool& rhs);
+	friend Tribool operator==(const Tribool& lhs, const IndeterminateKeywordType& rhs);
+
+	Tribool operator!=(const Tribool& other) const;
+	friend Tribool operator!=(const Tribool& lhs, bool rhs);
+	friend Tribool operator!=(bool lhs, const Tribool& rhs);
+	friend Tribool operator!=(const IndeterminateKeywordType& lhs, const Tribool& rhs);
+	friend Tribool operator!=(const Tribool& lhs, const IndeterminateKeywordType& rhs);
+
+	static inline bool Indeterminate(Tribool x, Tribool::IndeterminateType = Tribool::IndeterminateType())
+	{
+		return x.m_value == Tribool::TriboolValue::Indeterminate;
+	}
+
+private:
+	class TriboolValue
+	{
+	public:
+		enum type
+		{
+			True,
+			False,
+			Indeterminate
+		};
+	};
+
+private:
+	TriboolValue::type m_value;
+};
+
+
+template<typename CharT, typename Traits>
+inline std::basic_ostream<CharT, Traits>& operator<<(std::basic_ostream<CharT, Traits>& out, Tribool x)
+{
+	if (!Tribool::Indeterminate(x)) {
+		out << static_cast<bool>(x);
+	}
+	else
+	{
+		typename std::basic_ostream<CharT, Traits>::sentry cerberus(out);
+		if (cerberus)
+		{
+			if (out.flags() & std::ios_base::boolalpha)
+				out << "indeterminate";
+			else
+				out << 2;
+		}
+	}
+	return out;
+}
+
+template<typename CharT, typename Traits>
+inline std::basic_ostream<CharT, Traits>& operator<<(std::basic_ostream<CharT, Traits>& out, bool (*)(Tribool, Tribool::IndeterminateType))
+{
+	return out << Tribool(Tribool::Indeterminate);
+}
+
+template<typename CharT, typename Traits>
+std::basic_istream<CharT, Traits>& operator>>(std::basic_istream<CharT, Traits>& in, Tribool& x)
+{
+	if (in.flags() & std::ios_base::boolalpha)
+	{
+		typename std::basic_istream<CharT, Traits>::sentry cerberus(in);
+		if (cerberus)
+		{
+			typedef std::basic_string<CharT> string_type;
+
+			string_type falsename = "false";
+			string_type truename = "true";
+			string_type indeterminatename = "indeterminate";
+
+			typename string_type::size_type pos = 0;
+			bool falsename_ok = true;
+			bool truename_ok = true;
+			bool indeterminatename_ok = true;
+
+			while ((falsename_ok && pos < falsename.size()) || (truename_ok && pos < truename.size()) || (indeterminatename_ok && pos < indeterminatename.size()))
+			{
+				typename Traits::int_type c = in.get();
+				if (c == Traits::eof())
+					return in;
+
+				bool matched = false;
+				if (falsename_ok && pos < falsename.size())
+				{
+					if (Traits::eq(Traits::to_char_type(c), falsename[pos]))
+						matched = true;
+					else
+						falsename_ok = false;
+				}
+
+				if (truename_ok && pos < truename.size())
+				{
+					if (Traits::eq(Traits::to_char_type(c), truename[pos]))
+						matched = true;
+					else
+						truename_ok = false;
+				}
+
+				if (indeterminatename_ok && pos < indeterminatename.size())
+				{
+					if (Traits::eq(Traits::to_char_type(c), indeterminatename[pos]))
+						matched = true;
+					else
+						indeterminatename_ok = false;
+				}
+
+				if (matched)
+					++pos;
+				if (pos > falsename.size())
+					falsename_ok = false;
+				if (pos > truename.size())
+					truename_ok = false;
+				if (pos > indeterminatename.size())
+					indeterminatename_ok = false;
+			}
+
+			if (pos == 0)
+			{
+				in.setstate(std::ios_base::failbit);
+			}
+			else
+			{
+				if (falsename_ok)
+					x = false;
+				else if (truename_ok)
+					x = true;
+				else if (indeterminatename_ok)
+					x = Tribool::Indeterminate;
+				else
+					in.setstate(std::ios_base::failbit);
+			}
+		}
+	}
+	else
+	{
+		long value;
+		if (in >> value)
+		{
+			switch (value)
+			{
+			case 0:
+				x = false;
+				break;
+			case 1:
+				x = true;
+				break;
+			case 2:
+				x = Tribool::Indeterminate;
+				break;
+			default:
+				in.setstate(std::ios_base::failbit);
+				break;
+			}
+		}
+	}
+
+	return in;
+}
+
+} // namespace Utilities
+
+#endif // TRIBOOL_H