linux-packaging-mono/mcs/class/corlib/System/Boolean.cs

//
// System.Boolean.cs
//
// Author:
//   Derek Holden (dholden@draper.com)
//
// (C) Ximian, Inc.  http://www.ximian.com
//

//
// Copyright (C) 2004 Novell, Inc (http://www.novell.com)
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
// 
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
// Testing SVN 
//
// I guess this is the Boolean class. This was written word for word
// off the Library specification for System.Boolean in the ECMA
// TC39 TG2 and TG3 working documents.
//
// The XML style documentation isn't that elegant, but it seems to 
// be the standard way according to the poorly documented C# 
// Programmer's Reference section on XML Documentation.
//

using System.Globalization;
using System.Runtime.InteropServices;

namespace System
{
	/// <summary>
	/// Represents the boolean values of logical true and false.
	/// </summary>
	[Serializable]
	[ComVisible (true)]
	public struct Boolean : IComparable, IConvertible, IComparable <bool>, IEquatable <bool>
	{
		/// <value>
		/// The String representation of Boolean False
		/// </value>	
		public static readonly string FalseString = "False";

		/// <value>
		/// The String representation of Boolean True
		/// </value>	
		public static readonly string TrueString = "True";

		internal bool m_value;

		/// <summary>
		/// Compares the current Boolean instance against another object.
		/// </summary>
		/// <remarks>
		/// Throws an ArgumentException if <c>obj</c> isn't null or 
		/// a Boolean.
		/// </remarks>
		/// <param name="obj">
		/// The object to compare against
		/// </param>
		/// <returns>
		/// An int reflecting the sort order of this instance as 
		/// compared to <c>obj</c>
		/// -1 if this instance is false and <c>obj</c> is true
		///  0 if this instance is equal to <c>obj</c>
		///  1 if this instance is true and <c>obj</c> is false, 
		///    or <c>obj</c> is null
		/// </returns>
		public int CompareTo (object obj)
		{
			if (obj == null)
				return 1;

			if (!(obj is System.Boolean))
				throw new ArgumentException (Locale.GetText (
					"Object is not a Boolean."));

			bool value = (bool) obj;

			// for case #3
			if (m_value && !value)
				return 1;

			// for case #2, else it's #1
			return (m_value == value) ? 0 : -1;
		}

		/// <summary>
		/// Determines whether this instance and another object represent the
		/// same type and value.
		/// </summary>
		/// <param name="obj">
		/// The object to check against
		/// </param>
		/// <returns>
		/// true if this instnace and <c>obj</c> are same value, 
		/// otherwise false if it is not or null
		/// </returns>
		public override bool Equals (Object obj)
		{
			if (obj == null || !(obj is System.Boolean))
				return false;

			bool value = (bool) obj;

			return m_value ? value : !value;
		}

		public int CompareTo (bool value)
		{
			if (m_value == value)
				return 0;
			return !m_value ? -1 : 1;
		}

		public bool Equals (bool obj)
		{
			return m_value == obj;
		}

		/// <summary>
		/// Generates a hashcode for this object.
		/// </summary>
		/// <returns>
		/// An Int32 value holding the hash code
		/// </returns>
		public override int GetHashCode ()
		{
			// Guess there's not too many ways to hash a Boolean
			return m_value ? 1 : 0;
		}

		/// <summary>
		/// Returns a given string as a boolean value. The string must be 
		/// equivalent to either TrueString or FalseString, with leading and/or
		/// trailing spaces, and is parsed case-insensitively.
		/// </summary>
		/// <remarks>
		/// Throws an ArgumentNullException if <c>val</c> is null, or a 
		/// FormatException if <c>val</c> doesn't match <c>TrueString</c> 
		/// or <c>FalseString</c>
		/// </remarks>
		/// <param name="val">
		/// The string value to parse
		/// </param>
		/// <returns>
		/// true if <c>val</c> is equivalent to TrueString, 
		/// otherwise false
		/// </returns>
		public static bool Parse (string value)
		{
			if (value == null)
				throw new ArgumentNullException ("value");

			value = value.Trim ();

			if (string.CompareOrdinalCaseInsensitiveUnchecked (value, TrueString) == 0)
				return true;

			if (string.CompareOrdinalCaseInsensitiveUnchecked (value, FalseString) == 0)
				return false;

			throw new FormatException (Locale.GetText (
				"Value is not equivalent to either TrueString or FalseString."));
		}

		public static bool TryParse (string value, out bool result)
		{
			result = false;
			if (value == null)
				return false;

			value = value.Trim ();

			if (string.CompareOrdinalCaseInsensitiveUnchecked (value, TrueString) == 0) {
				result = true;
				return true;
			}

			if (string.CompareOrdinalCaseInsensitiveUnchecked (value, FalseString) == 0) {
				// result = false; // already set at false by default
				return true;
			}

			return false;
		}

		/// <summary>
		/// Returns a string representation of this Boolean object.
		/// </summary>
		/// <returns>
		/// <c>FalseString</c> if the instance value is false, otherwise 
		/// <c>TrueString</c>
		/// </returns>
		public override string ToString ()
		{
			return m_value ? TrueString : FalseString;
		}

		// =========== IConvertible Methods =========== //
		public TypeCode GetTypeCode ()
		{
			return TypeCode.Boolean;
		}

		object IConvertible.ToType (Type targetType, IFormatProvider provider)
		{
			if (targetType == null)
				throw new ArgumentNullException ("targetType");
			return System.Convert.ToType (m_value, targetType, provider, false);
		}

		bool IConvertible.ToBoolean (IFormatProvider provider)
		{
			return m_value;
		}

		byte IConvertible.ToByte (IFormatProvider provider)
		{
			return System.Convert.ToByte (m_value);
		}

		char IConvertible.ToChar (IFormatProvider provider)
		{
			throw new InvalidCastException ();
		}

		DateTime IConvertible.ToDateTime (IFormatProvider provider)
		{
			throw new InvalidCastException ();
		}

		decimal IConvertible.ToDecimal (IFormatProvider provider)
		{
			return System.Convert.ToDecimal (m_value);
		}

		double IConvertible.ToDouble (IFormatProvider provider)
		{
			return System.Convert.ToDouble (m_value);
		}

		short IConvertible.ToInt16 (IFormatProvider provider)
		{
			return System.Convert.ToInt16 (m_value);
		}

		int IConvertible.ToInt32 (IFormatProvider provider)
		{
			return System.Convert.ToInt32 (m_value);
		}

		long IConvertible.ToInt64 (IFormatProvider provider)
		{
			return System.Convert.ToInt64 (m_value);
		}

		sbyte IConvertible.ToSByte (IFormatProvider provider)
		{
			return System.Convert.ToSByte (m_value);
		}

		float IConvertible.ToSingle (IFormatProvider provider)
		{
			return System.Convert.ToSingle (m_value);
		}

		public string ToString (IFormatProvider provider)
		{
			return ToString ();
		}

		ushort IConvertible.ToUInt16 (IFormatProvider provider)
		{
			return System.Convert.ToUInt16 (m_value);
		}

		uint IConvertible.ToUInt32 (IFormatProvider provider)
		{
			return System.Convert.ToUInt32 (m_value);
		}

		ulong IConvertible.ToUInt64 (IFormatProvider provider)
		{
			return System.Convert.ToUInt64 (m_value);
		}
	}
}