Code:
/ DotNET / DotNET / 8.0 / untmp / whidbey / REDBITS / ndp / clr / src / BCL / System / Double.cs / 1 / Double.cs
// ==++== // // Copyright (c) Microsoft Corporation. All rights reserved. // // ==--== /*============================================================ ** ** Class: Double ** ** ** Purpose: A representation of an IEEE double precision ** floating point number. ** ** ===========================================================*/ namespace System { using System; using System.Globalization; using System.Runtime.InteropServices; using System.Runtime.CompilerServices; using System.Runtime.ConstrainedExecution; [Serializable, StructLayout(LayoutKind.Sequential)] [System.Runtime.InteropServices.ComVisible(true)] public struct Double : IComparable, IFormattable, IConvertible #if GENERICS_WORK , IComparable, IEquatable #endif { internal double m_value; // // Public Constants // public const double MinValue = -1.7976931348623157E+308; public const double MaxValue = 1.7976931348623157E+308; // Note Epsilon should be a double whose hex representation is 0x1 // on little endian machines. public const double Epsilon = 4.9406564584124654E-324; public const double NegativeInfinity = (double)-1.0 / (double)(0.0); public const double PositiveInfinity = (double)1.0 / (double)(0.0); public const double NaN = (double)0.0 / (double)0.0; internal static double NegativeZero = BitConverter.Int64BitsToDouble(unchecked((long)0x8000000000000000)); public unsafe static bool IsInfinity(double d) { return (*(long*)(&d) & 0x7FFFFFFFFFFFFFFF) == 0x7FF0000000000000; } public static bool IsPositiveInfinity(double d) { //Jit will generate inlineable code with this if (d == double.PositiveInfinity) { return true; } else { return false; } } public static bool IsNegativeInfinity(double d) { //Jit will generate inlineable code with this if (d == double.NegativeInfinity) { return true; } else { return false; } } internal unsafe static bool IsNegative(double d) { return (*(UInt64*)(&d) & 0x8000000000000000) == 0x8000000000000000; } [ReliabilityContract(Consistency.WillNotCorruptState, Cer.Success)] public static bool IsNaN(double d) { //Jit will generate inlineable code with this // warning CS1718: comparison to same variable #pragma warning disable 1718 if (d != d) { return true; } else { return false; } #pragma warning restore 1718 } // Compares this object to another object, returning an instance of System.Relation. // Null is considered less than any instance. // // If object is not of type Double, this method throws an ArgumentException. // // Returns a value less than zero if this object // public int CompareTo(Object value) { if (value == null) { return 1; } if (value is Double) { double d = (double)value; if (m_value < d) return -1; if (m_value > d) return 1; if (m_value == d) return 0; // At least one of the values is NaN. if (IsNaN(m_value)) return (IsNaN(d) ? 0 : -1); else return 1; } throw new ArgumentException(Environment.GetResourceString("Arg_MustBeDouble")); } public int CompareTo(Double value) { if (m_value < value) return -1; if (m_value > value) return 1; if (m_value == value) return 0; // At least one of the values is NaN. if (IsNaN(m_value)) return (IsNaN(value) ? 0 : -1); else return 1; } // True if obj is another Double with the same value as the current instance. This is // a method of object equality, that only returns true if obj is also a double. public override bool Equals(Object obj) { if (!(obj is Double)) { return false; } double temp = ((Double)obj).m_value; // This code below is written this way for performance reasons i.e the != and == check is intentional. if (temp == m_value) { return true; } return IsNaN(temp) && IsNaN(m_value); } public bool Equals(Double obj) { if (obj == m_value) { return true; } return IsNaN(obj) && IsNaN(m_value); } //The hashcode for a double is the absolute value of the integer representation //of that double. // public unsafe override int GetHashCode() { double d = m_value; if (d == 0) { // Ensure that 0 and -0 have the same hash code return 0; } long value = *(long*)(&d); return unchecked((int)value) ^ ((int)(value >> 32)); } public override String ToString() { return Number.FormatDouble(m_value, null, NumberFormatInfo.CurrentInfo); } public String ToString(String format) { return Number.FormatDouble(m_value, format, NumberFormatInfo.CurrentInfo); } public String ToString(IFormatProvider provider) { return Number.FormatDouble(m_value, null, NumberFormatInfo.GetInstance(provider)); } public String ToString(String format, IFormatProvider provider) { return Number.FormatDouble(m_value, format, NumberFormatInfo.GetInstance(provider)); } public static double Parse(String s) { return Parse(s, NumberStyles.Float| NumberStyles.AllowThousands, NumberFormatInfo.CurrentInfo); } public static double Parse(String s, NumberStyles style) { NumberFormatInfo.ValidateParseStyleFloatingPoint(style); return Parse(s, style, NumberFormatInfo.CurrentInfo); } public static double Parse(String s, IFormatProvider provider) { return Parse(s, NumberStyles.Float| NumberStyles.AllowThousands, NumberFormatInfo.GetInstance(provider)); } public static double Parse(String s, NumberStyles style, IFormatProvider provider) { NumberFormatInfo.ValidateParseStyleFloatingPoint(style); return Parse(s, style, NumberFormatInfo.GetInstance(provider)); } // Parses a double from a String in the given style. If // a NumberFormatInfo isn't specified, the current culture's // NumberFormatInfo is assumed. // // This method will not throw an OverflowException, but will return // PositiveInfinity or NegativeInfinity for a number that is too // large or too small. // private static double Parse(String s, NumberStyles style, NumberFormatInfo info) { try { return Number.ParseDouble(s, style, info); } catch (FormatException) { //If we caught a FormatException, it may be from one of our special strings. //Check the three with which we're concerned and rethrow if it's not one of //those strings. String sTrim = s.Trim(); if (sTrim.Equals(info.PositiveInfinitySymbol)) { return PositiveInfinity; } if (sTrim.Equals(info.NegativeInfinitySymbol)) { return NegativeInfinity; } if (sTrim.Equals(info.NaNSymbol)) { return NaN; } //Rethrow the previous exception; throw; } } public static bool TryParse(String s, out double result) { return TryParse(s, NumberStyles.Float| NumberStyles.AllowThousands, NumberFormatInfo.CurrentInfo, out result); } public static bool TryParse(String s, NumberStyles style, IFormatProvider provider, out double result) { NumberFormatInfo.ValidateParseStyleFloatingPoint(style); return TryParse(s, style, NumberFormatInfo.GetInstance(provider), out result); } private static bool TryParse(String s, NumberStyles style, NumberFormatInfo info, out double result) { if (s == null) { result = 0; return false; } bool success = Number.TryParseDouble(s, style, info, out result); if (!success) { String sTrim = s.Trim(); if (sTrim.Equals(info.PositiveInfinitySymbol)) { result = PositiveInfinity; } else if (sTrim.Equals(info.NegativeInfinitySymbol)) { result = NegativeInfinity; } else if (sTrim.Equals(info.NaNSymbol)) { result = NaN; } else return false; // We really failed } return true; } // // IValue implementation // public TypeCode GetTypeCode() { return TypeCode.Double; } /// bool IConvertible.ToBoolean(IFormatProvider provider) { return Convert.ToBoolean(m_value); } /// char IConvertible.ToChar(IFormatProvider provider) { throw new InvalidCastException(String.Format(CultureInfo.CurrentCulture, Environment.GetResourceString("InvalidCast_FromTo"), "Double", "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 m_value; } /// Decimal IConvertible.ToDecimal(IFormatProvider provider) { return Convert.ToDecimal(m_value); } /// DateTime IConvertible.ToDateTime(IFormatProvider provider) { throw new InvalidCastException(String.Format(CultureInfo.CurrentCulture, Environment.GetResourceString("InvalidCast_FromTo"), "Double", "DateTime")); } /// Object IConvertible.ToType(Type type, IFormatProvider provider) { return Convert.DefaultToType((IConvertible)this, type, provider); } } }
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