Fix Abbreviated Genitive Month Names Parsing

src/System.Private.CoreLib/shared/System/Globalization/DateTimeFormatInfo.cs

@@ -1338,7 +1338,7 @@ internal string InternalGetMonthName(int month, MonthNameStyles style, bool abbr
 
         /// <summary>
         /// Retrieve the array which contains the month names in genitive form.
-        /// If this culture does not use the gentive form, the normal month name is returned.
+        /// If this culture does not use the genitive form, the normal month name is returned.
         /// </summary>
         private string[] InternalGetGenitiveMonthNames(bool abbreviated)
         {
@@ -2301,14 +2301,15 @@ internal TokenHashValue[] CreateTokenHashTable()
                     InsertHash(temp, GetAbbreviatedMonthName(i), TokenType.MonthToken, i);
                 }
 
-
                 if ((FormatFlags & DateTimeFormatFlags.UseGenitiveMonth) != 0)
                 {
+                    string [] genitiveMonthNames = InternalGetGenitiveMonthNames(abbreviated: false);
+                    string [] abbreviatedGenitiveMonthNames = InternalGetGenitiveMonthNames(abbreviated: true);
+
                     for (int i = 1; i <= 13; i++)
                     {
-                        string str;
-                        str = InternalGetMonthName(i, MonthNameStyles.Genitive, false);
-                        InsertHash(temp, str, TokenType.MonthToken, i);
+                        InsertHash(temp, genitiveMonthNames[i - 1], TokenType.MonthToken, i);
+                        InsertHash(temp, abbreviatedGenitiveMonthNames[i - 1], TokenType.MonthToken, i);
                     }
                 }
 

src/System.Private.CoreLib/shared/System/Globalization/DateTimeFormatInfoScanner.cs

@@ -344,10 +344,10 @@ internal static int ScanRepeatChar(string pattern, char ch, int index, out int c
 
         ////////////////////////////////////////////////////////////////////////////
         //
-        // Add the text that is a date separator but is treated like ignroable symbol.
+        // Add the text that is a date separator but is treated like ignorable symbol.
         // E.g.
         // hu-HU has:
-        //      shrot date pattern: yyyy. MM. dd.;yyyy-MM-dd;yy-MM-dd
+        //      short date pattern: yyyy. MM. dd.;yyyy-MM-dd;yy-MM-dd
         //      long date pattern: yyyy. MMMM d.
         // Here, "." is the date separator (derived from short date pattern). However,
         // "." also appear at the end of long date pattern.  In this case, we just
@@ -604,7 +604,7 @@ internal static FORMATFLAGS GetFormatFlagUseHebrewCalendar(int calID)
         //-----------------------------------------------------------------------------
         // EqualStringArrays
         //      compares two string arrays and return true if all elements of the first
-        //      array equals to all elmentsof the second array.
+        //      array equals to all elements of the second array.
         //      otherwise it returns false.
         //-----------------------------------------------------------------------------
 

src/System.Private.CoreLib/shared/System/Globalization/DateTimeParse.cs

@@ -3303,7 +3303,7 @@ private static bool ParseTimeZoneOffset(ref __DTString str, int len, ref TimeSpa
 
         /*=================================MatchAbbreviatedMonthName==================================
         **Action: Parse the abbreviated month name from string starting at str.Index.
-        **Returns: A value from 1 to 12 for the first month to the twelveth month.
+        **Returns: A value from 1 to 12 for the first month to the twelfth month.
         **Arguments:    str: a __DTString.  The parsing will start from the
         **              next character after str.Index.
         **Exceptions: FormatException if an abbreviated month name can not be found.
@@ -3338,6 +3338,19 @@ private static bool MatchAbbreviatedMonthName(ref __DTString str, DateTimeFormat
                     }
                 }
 
+                // Search genitive form.
+                if ((dtfi.FormatFlags & DateTimeFormatFlags.UseGenitiveMonth) != 0)
+                {
+                    int tempResult = str.MatchLongestWords(dtfi.AbbreviatedMonthGenitiveNames, ref maxMatchStrLen);
+                    // We found a longer match in the genitive month name.  Use this as the result.
+                    // The result from MatchLongestWords is 0 ~ length of word array.
+                    // So we increment the result by one to become the month value.
+                    if (tempResult >= 0)
+                    {
+                        result = tempResult + 1;
+                    }
+                }
+
                 // Search leap year form.
                 if ((dtfi.FormatFlags & DateTimeFormatFlags.UseLeapYearMonth) != 0)
                 {
@@ -3361,7 +3374,7 @@ private static bool MatchAbbreviatedMonthName(ref __DTString str, DateTimeFormat
 
         /*=================================MatchMonthName==================================
         **Action: Parse the month name from string starting at str.Index.
-        **Returns: A value from 1 to 12 indicating the first month to the twelveth month.
+        **Returns: A value from 1 to 12 indicating the first month to the twelfth month.
         **Arguments:    str: a __DTString.  The parsing will start from the
         **              next character after str.Index.
         **Exceptions: FormatException if a month name can not be found.