src/mscorlib/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 Microsoft.Win32;
   6
   7 namespace System.Globalization
   8 {
   9     public partial class HijriCalendar : Calendar
  10     {
  11         private int GetHijriDateAdjustment()
  12         {
  13             if (_hijriAdvance == Int32.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             int hijriAdvance = 0;
  43             Microsoft.Win32.RegistryKey key = null;
  44
  45             try
  46             {
  47                 // Open in read-only mode.
  48                 key = RegistryKey.GetBaseKey(RegistryKey.HKEY_CURRENT_USER).OpenSubKey(InternationalRegKey, false);
  49             }
  50             //If this fails for any reason, we'll just return 0.
  51             catch (ObjectDisposedException) { return 0; }
  52             catch (ArgumentException) { return 0; }
  53
  54             if (key != null)
  55             {
  56                 try
  57                 {
  58                     Object value = key.InternalGetValue(HijriAdvanceRegKeyEntry, null, false, false);
  59                     if (value == null)
  60                     {
  61                         return (0);
  62                     }
  63                     String str = value.ToString();
  64                     if (String.Compare(str, 0, HijriAdvanceRegKeyEntry, 0, HijriAdvanceRegKeyEntry.Length, StringComparison.OrdinalIgnoreCase) == 0)
  65                     {
  66                         if (str.Length == HijriAdvanceRegKeyEntry.Length)
  67                             hijriAdvance = -1;
  68                         else
  69                         {
  70                             try
  71                             {
  72                                 int advance = Int32.Parse(str.AsSpan(HijriAdvanceRegKeyEntry.Length), provider:CultureInfo.InvariantCulture);
  73                                 if ((advance >= MinAdvancedHijri) && (advance <= MaxAdvancedHijri))
  74                                 {
  75                                     hijriAdvance = advance;
  76                                 }
  77                             }
  78                             // If we got garbage from registry just ignore it.
  79                             // hijriAdvance = 0 because of declaraction assignment up above.
  80                             catch (ArgumentException) { }
  81                             catch (FormatException) { }
  82                             catch (OverflowException) { }
  83                         }
  84                     }
  85                 }
  86                 finally
  87                 {
  88                     key.Close();
  89                 }
  90             }
  91             return (hijriAdvance);
  92         }
  93     }
  94 }