Boolean.cs source code in C# .NET

Source code for the .NET framework in C#

                        

Code:

/ 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / clr / src / BCL / System / Boolean.cs / 1305376 / Boolean.cs

                            // ==++== 
//
//   Copyright (c) Microsoft Corporation.  All rights reserved.
//
// ==--== 
/*============================================================
** 
** Class:  Boolean 
**
** 
** Purpose: The boolean class serves as a wrapper for the primitive
** type boolean.
**
** 
===========================================================*/
namespace System { 
 
    using System;
    using System.Globalization; 
    using System.Diagnostics.Contracts;
    // The Boolean class provides the
    // object representation of the boolean primitive type.
    [Serializable] 
[System.Runtime.InteropServices.ComVisible(true)]
    public struct Boolean : IComparable, IConvertible 
#if GENERICS_WORK 
        , IComparable,  IEquatable
#endif 
    {

      //
      // Member Variables 
      //
      private bool m_value; 
 
      // The true value.
      // 
      internal const int True = 1;

      // The false value.
      // 
      internal const int False = 0;
 
 
      //
      // Internal Constants are real consts for performance. 
      //

      // The internal string representation of true.
      // 
      internal const String TrueLiteral  = "True";
 
      // The internal string representation of false. 
      //
      internal const String FalseLiteral = "False"; 


      //
      // Public Constants 
      //
 
      // The public string representation of true. 
      //
      public static readonly String TrueString  = TrueLiteral; 

      // The public string representation of false.
      //
      public static readonly String FalseString = FalseLiteral; 

      // 
      // Overriden Instance Methods 
      //
      /*=================================GetHashCode================================== 
      **Args:  None
      **Returns: 1 or 0 depending on whether this instance represents true or false.
      **Exceptions: None
      **Overriden From: Value 
      ==============================================================================*/
      // Provides a hash code for this instance. 
      public override int GetHashCode() { 
          return (m_value)?True:False;
      } 

      /*===================================ToString===================================
      **Args: None
      **Returns:  "True" or "False" depending on the state of the boolean. 
      **Exceptions: None.
      ==============================================================================*/ 
      // Converts the boolean value of this instance to a String. 
      public override String ToString() {
        if (false == m_value) { 
          return FalseLiteral;
        }
        return TrueLiteral;
      } 

      public String ToString(IFormatProvider provider) { 
        if (false == m_value) { 
          return FalseLiteral;
        } 
        return TrueLiteral;
      }

      // Determines whether two Boolean objects are equal. 
      public override bool Equals (Object obj) {
        //If it's not a boolean, we're definitely not equal 
        if (!(obj is Boolean)) { 
          return false;
        } 

        return (m_value==((Boolean)obj).m_value);
      }
 
      public bool Equals(Boolean obj)
      { 
          return m_value == obj; 
      }
 
        // Compares this object to another object, returning an integer that
        // indicates the relationship. For booleans, false sorts before true.
        // null is considered to be less than any instance.
        // If object is not of type boolean, this method throws an ArgumentException. 
        //
        // Returns a value less than zero if this  object 
        // 
        public int CompareTo(Object obj) {
            if (obj==null) { 
                return 1;
            }
            if (!(obj is Boolean)) {
                throw new ArgumentException (Environment.GetResourceString("Arg_MustBeBoolean")); 
            }
 
            if (m_value==((Boolean)obj).m_value) { 
                return 0;
            } else if (m_value==false) { 
                return -1;
            }
            return 1;
        } 

        public int CompareTo(Boolean value) { 
            if (m_value==value) { 
                return 0;
            } else if (m_value==false) { 
                return -1;
            }
            return 1;
        } 

        // 
        // Static Methods 
        //
 
        // Determines whether a String represents true or false.
        //
        public static Boolean Parse (String value) {
            if (value==null) throw new ArgumentNullException("value"); 
            Contract.EndContractBlock();
            Boolean result = false; 
            if (!TryParse(value, out result)) { 
                throw new FormatException(Environment.GetResourceString("Format_BadBoolean"));
            } 
            else {
                return result;
            }
        } 

        // Determines whether a String represents true or false. 
        // 
        public static Boolean TryParse (String value, out Boolean result) {
            result = false; 
            if (value==null) {
                return false;
            }
            // For perf reasons, let's first see if they're equal, then do the 
            // trim to get rid of white space, and check again.
            if (TrueLiteral.Equals(value, StringComparison.OrdinalIgnoreCase)) { 
                result = true; 
                return true;
            } 
            if (FalseLiteral.Equals(value,StringComparison.OrdinalIgnoreCase)) {
                result = false;
                return true;
            } 

            // Special case: Trim whitespace as well as null characters. 
            value = TrimWhiteSpaceAndNull(value); 

            if (TrueLiteral.Equals(value, StringComparison.OrdinalIgnoreCase)) { 
                result = true;
                return true;
            }
 
            if (FalseLiteral.Equals(value,StringComparison.OrdinalIgnoreCase)) {
                result = false; 
                return true; 
            }
 
            return false;
        }

        private static String TrimWhiteSpaceAndNull(String value) { 
            int start = 0;
            int end   = value.Length-1; 
            char nullChar = (char) 0x0000; 

            while (start < value.Length) { 
                if (!Char.IsWhiteSpace(value[start]) && value[start] != nullChar) {
                    break;
                }
                start++; 
            }
 
            while (end >= start) { 
                if (!Char.IsWhiteSpace(value[end]) && value[end] != nullChar) {
                    break; 
                }
                end--;
            }
 
            return value.Substring(start, end - start + 1);
        } 
 
        //
        // IConvertible implementation 
        //

        public TypeCode GetTypeCode() {
            return TypeCode.Boolean; 
        }
 
 
        /// 
        bool IConvertible.ToBoolean(IFormatProvider provider) { 
            return m_value;
        }

        ///  
        char IConvertible.ToChar(IFormatProvider provider) {
            throw new InvalidCastException(Environment.GetResourceString("InvalidCast_FromTo", "Boolean", "Char")); 
        } 

        ///  
        sbyte IConvertible.ToSByte(IFormatProvider provider) {
            return Convert.ToSByte(m_value);
        }
 
        /// 
        byte IConvertible.ToByte(IFormatProvider provider) { 
            return Convert.ToByte(m_value); 
        }
 
        /// 
        short IConvertible.ToInt16(IFormatProvider provider) {
            return Convert.ToInt16(m_value);
        } 

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

        /// 
        int IConvertible.ToInt32(IFormatProvider provider) {
            return Convert.ToInt32(m_value); 
        }
 
        ///  
        uint IConvertible.ToUInt32(IFormatProvider provider) {
            return Convert.ToUInt32(m_value); 
        }

        /// 
        long IConvertible.ToInt64(IFormatProvider provider) { 
            return Convert.ToInt64(m_value);
        } 
 
        /// 
        ulong IConvertible.ToUInt64(IFormatProvider provider) { 
            return Convert.ToUInt64(m_value);
        }

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

        ///  
        double IConvertible.ToDouble(IFormatProvider provider) {
            return Convert.ToDouble(m_value);
        }
 
        /// 
        Decimal IConvertible.ToDecimal(IFormatProvider provider) { 
            return Convert.ToDecimal(m_value); 
        }
 
        /// 
        DateTime IConvertible.ToDateTime(IFormatProvider provider) {
            throw new InvalidCastException(Environment.GetResourceString("InvalidCast_FromTo", "Boolean", "DateTime"));
        } 

        ///  
        Object IConvertible.ToType(Type type, IFormatProvider provider) { 
            return Convert.DefaultToType((IConvertible)this, type, provider);
        } 
    }
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
                        

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