netcore/System.Private.CoreLib/shared/System/Globalization/HijriCalendar.Win32.cs

   1 // Licensed to the .NET Foundation under one or more agreements.
   2 // The .NET Foundation licenses this file to you under the MIT license.
   3 // See the LICENSE file in the project root for more information.
   4
   5 using Internal.Win32;
   6
   7 namespace System.Globalization
   8 {
   9     public partial class HijriCalendar : Calendar
  10     {
  11         private int GetHijriDateAdjustment()
  12         {
  13             if (_hijriAdvance == int.MinValue)
  14             {
  15                 // Never been set before.  Use the system value from registry.
  16                 _hijriAdvance = GetAdvanceHijriDate();
  17             }
  18             return _hijriAdvance;
  19         }
  20
  21         private const string InternationalRegKey = "Control Panel\\International";
  22         private const string HijriAdvanceRegKeyEntry = "AddHijriDate";
  23
  24         /*=================================GetAdvanceHijriDate==========================
  25         **Action: Gets the AddHijriDate value from the registry.
  26         **Returns:
  27         **Arguments:    None.
  28         **Exceptions:
  29         **Note:
  30         **  The HijriCalendar has a user-overidable calculation.  That is, use can set a value from the control
  31         **  panel, so that the calculation of the Hijri Calendar can move ahead or backwards from -2 to +2 days.
  32         **
  33         **  The valid string values in the registry are:
  34         **      "AddHijriDate-2"  =>  Add -2 days to the current calculated Hijri date.
  35         **      "AddHijriDate"    =>  Add -1 day to the current calculated Hijri date.
  36         **      ""              =>  Add 0 day to the current calculated Hijri date.
  37         **      "AddHijriDate+1"  =>  Add +1 days to the current calculated Hijri date.
  38         **      "AddHijriDate+2"  =>  Add +2 days to the current calculated Hijri date.
  39         ============================================================================*/
  40         private static int GetAdvanceHijriDate()
  41         {
  42             using (RegistryKey? key = Registry.CurrentUser.OpenSubKey(InternationalRegKey))
  43             {
  44                 // Abort if we didn't find anything
  45                 if (key == null)
  46                 {
  47                     return 0;
  48                 }
  49
  50                 object? value = key.GetValue(HijriAdvanceRegKeyEntry);
  51                 if (value == null)
  52                 {
  53                     return 0;
  54                 }
  55
  56                 int hijriAdvance = 0;
  57                 string? str = value.ToString();
  58                 if (string.Compare(str, 0, HijriAdvanceRegKeyEntry, 0, HijriAdvanceRegKeyEntry.Length, StringComparison.OrdinalIgnoreCase) == 0)
  59                 {
  60                     if (str!.Length == HijriAdvanceRegKeyEntry.Length)
  61                         hijriAdvance = -1;
  62                     else
  63                     {
  64                         try
  65                         {
  66                             int advance = int.Parse(str.AsSpan(HijriAdvanceRegKeyEntry.Length), provider: CultureInfo.InvariantCulture);
  67                             if ((advance >= MinAdvancedHijri) && (advance <= MaxAdvancedHijri))
  68                             {
  69                                 hijriAdvance = advance;
  70                             }
  71                         }
  72                         // If we got garbage from registry just ignore it.
  73                         // hijriAdvance = 0 because of declaraction assignment up above.
  74                         catch (ArgumentException) { }
  75                         catch (FormatException) { }
  76                         catch (OverflowException) { }
  77                     }
  78                 }
  79                 return hijriAdvance;
  80             }
  81         }
  82     }
  83 }