3 files changed, 140 insertions, 142 deletions
diff --git a/MediaBrowser.Controller/Sorting/AlphanumComparator.cs b/MediaBrowser.Controller/Sorting/AlphanumComparator.cs
new file mode 100644
index 000000000..de7f72d1c
--- /dev/null
+++ b/MediaBrowser.Controller/Sorting/AlphanumComparator.cs
@@ -0,0 +1,135 @@
+#nullable enable
+
+using System;
+using System.Collections.Generic;
+
+namespace MediaBrowser.Controller.Sorting
+{
+    public class AlphanumComparator : IComparer<string?>
+    {
+        public static int CompareValues(string? s1, string? s2)
+        {
+            if (s1 == null && s2 == null)
+            {
+                return 0;
+            }
+            else if (s1 == null)
+            {
+                return -1;
+            }
+            else if (s2 == null)
+            {
+                return 1;
+            }
+
+            int len1 = s1.Length;
+            int len2 = s2.Length;
+
+            // Early return for empty strings
+            if (len1 == 0 && len2 == 0)
+            {
+                return 0;
+            }
+            else if (len1 == 0)
+            {
+                return -1;
+            }
+            else if (len2 == 0)
+            {
+                return 1;
+            }
+
+            int pos1 = 0;
+            int pos2 = 0;
+
+            do
+            {
+                int start1 = pos1;
+                int start2 = pos2;
+
+                bool isNum1 = char.IsDigit(s1[pos1++]);
+                bool isNum2 = char.IsDigit(s2[pos2++]);
+
+                while (pos1 < len1 && char.IsDigit(s1[pos1]) == isNum1)
+                {
+                    pos1++;
+                }
+
+                while (pos2 < len2 && char.IsDigit(s2[pos2]) == isNum2)
+                {
+                    pos2++;
+                }
+
+                var span1 = s1.AsSpan(start1, pos1 - start1);
+                var span2 = s2.AsSpan(start2, pos2 - start2);
+
+                if (isNum1 && isNum2)
+                {
+                    // Trim leading zeros so we can compare the length
+                    // of the strings to find the largest number
+                    span1 = span1.TrimStart('0');
+                    span2 = span2.TrimStart('0');
+                    var span1Len = span1.Length;
+                    var span2Len = span2.Length;
+                    if (span1Len < span2Len)
+                    {
+                        return -1;
+                    }
+                    else if (span1Len > span2Len)
+                    {
+                        return 1;
+                    }
+                    else if (span1Len >= 20) // Number is probably too big for a ulong
+                    {
+                        // Trim all the first digits that are the same
+                        int i = 0;
+                        while (i < span1Len && span1[i] == span2[i])
+                        {
+                            i++;
+                        }
+
+                        // If there are no more digits it's the same number
+                        if (i == span1Len)
+                        {
+                            continue;
+                        }
+
+                        // Only need to compare the most significant digit
+                        span1 = span1.Slice(i, 1);
+                        span2 = span2.Slice(i, 1);
+                    }
+
+                    if (!ulong.TryParse(span1, out var num1)
+                        || !ulong.TryParse(span2, out var num2))
+                    {
+                        return 0;
+                    }
+                    else if (num1 < num2)
+                    {
+                        return -1;
+                    }
+                    else if (num1 > num2)
+                    {
+                        return 1;
+                    }
+                }
+                else
+                {
+                    int result = span1.CompareTo(span2, StringComparison.InvariantCulture);
+                    if (result != 0)
+                    {
+                        return result;
+                    }
+                }
+            } while (pos1 < len1 && pos2 < len2);
+
+            return len1 - len2;
+        }
+
+        /// <inheritdoc />
+        public int Compare(string x, string y)
+        {
+            return CompareValues(x, y);
+        }
+    }
+}
diff --git a/MediaBrowser.Controller/Sorting/SortExtensions.cs b/MediaBrowser.Controller/Sorting/SortExtensions.cs
index 111f4f17f..f5ee574a2 100644
--- a/MediaBrowser.Controller/Sorting/SortExtensions.cs
+++ b/MediaBrowser.Controller/Sorting/SortExtensions.cs
@@ -7,137 +7,25 @@ namespace MediaBrowser.Controller.Sorting
 {
     public static class SortExtensions
     {
+        private static readonly AlphanumComparator _comparer = new AlphanumComparator();
         public static IEnumerable<T> OrderByString<T>(this IEnumerable<T> list, Func<T, string> getName)
         {
-            return list.OrderBy(getName, new AlphanumComparator());
+            return list.OrderBy(getName, _comparer);
         }
 
         public static IEnumerable<T> OrderByStringDescending<T>(this IEnumerable<T> list, Func<T, string> getName)
         {
-            return list.OrderByDescending(getName, new AlphanumComparator());
+            return list.OrderByDescending(getName, _comparer);
         }
 
         public static IOrderedEnumerable<T> ThenByString<T>(this IOrderedEnumerable<T> list, Func<T, string> getName)
         {
-            return list.ThenBy(getName, new AlphanumComparator());
+            return list.ThenBy(getName, _comparer);
         }
 
         public static IOrderedEnumerable<T> ThenByStringDescending<T>(this IOrderedEnumerable<T> list, Func<T, string> getName)
         {
-            return list.ThenByDescending(getName, new AlphanumComparator());
-        }
-
-        private class AlphanumComparator : IComparer<string>
-        {
-            private enum ChunkType { Alphanumeric, Numeric };
-
-            private static bool InChunk(char ch, char otherCh)
-            {
-                var type = ChunkType.Alphanumeric;
-
-                if (char.IsDigit(otherCh))
-                {
-                    type = ChunkType.Numeric;
-                }
-
-                if ((type == ChunkType.Alphanumeric && char.IsDigit(ch))
-                    || (type == ChunkType.Numeric && !char.IsDigit(ch)))
-                {
-                    return false;
-                }
-
-                return true;
-            }
-
-            public static int CompareValues(string s1, string s2)
-            {
-                if (s1 == null || s2 == null)
-                {
-                    return 0;
-                }
-
-                int thisMarker = 0, thisNumericChunk = 0;
-                int thatMarker = 0, thatNumericChunk = 0;
-
-                while ((thisMarker < s1.Length) || (thatMarker < s2.Length))
-                {
-                    if (thisMarker >= s1.Length)
-                    {
-                        return -1;
-                    }
-                    else if (thatMarker >= s2.Length)
-                    {
-                        return 1;
-                    }
-                    char thisCh = s1[thisMarker];
-                    char thatCh = s2[thatMarker];
-
-                    var thisChunk = new StringBuilder();
-                    var thatChunk = new StringBuilder();
-
-                    while ((thisMarker < s1.Length) && (thisChunk.Length == 0 || InChunk(thisCh, thisChunk[0])))
-                    {
-                        thisChunk.Append(thisCh);
-                        thisMarker++;
-
-                        if (thisMarker < s1.Length)
-                        {
-                            thisCh = s1[thisMarker];
-                        }
-                    }
-
-                    while ((thatMarker < s2.Length) && (thatChunk.Length == 0 || InChunk(thatCh, thatChunk[0])))
-                    {
-                        thatChunk.Append(thatCh);
-                        thatMarker++;
-
-                        if (thatMarker < s2.Length)
-                        {
-                            thatCh = s2[thatMarker];
-                        }
-                    }
-
-                    int result = 0;
-                    // If both chunks contain numeric characters, sort them numerically
-                    if (char.IsDigit(thisChunk[0]) && char.IsDigit(thatChunk[0]))
-                    {
-                        if (!int.TryParse(thisChunk.ToString(), out thisNumericChunk))
-                        {
-                            return 0;
-                        }
-                        if (!int.TryParse(thatChunk.ToString(), out thatNumericChunk))
-                        {
-                            return 0;
-                        }
-
-                        if (thisNumericChunk < thatNumericChunk)
-                        {
-                            result = -1;
-                        }
-
-                        if (thisNumericChunk > thatNumericChunk)
-                        {
-                            result = 1;
-                        }
-                    }
-                    else
-                    {
-                        result = thisChunk.ToString().CompareTo(thatChunk.ToString());
-                    }
-
-                    if (result != 0)
-                    {
-                        return result;
-                    }
-                }
-
-                return 0;
-            }
-
-            public int Compare(string x, string y)
-            {
-                return CompareValues(x, y);
-            }
+            return list.ThenByDescending(getName, _comparer);
         }
     }
 }
diff --git a/MediaBrowser.Controller/Sorting/SortHelper.cs b/MediaBrowser.Controller/Sorting/SortHelper.cs
deleted file mode 100644
index 05981d975..000000000
--- a/MediaBrowser.Controller/Sorting/SortHelper.cs
+++ /dev/null
@@ -1,25 +0,0 @@
-namespace MediaBrowser.Controller.Sorting
-{
-    public static class SortHelper
-    {
-        private enum ChunkType { Alphanumeric, Numeric };
-
-        public static bool InChunk(char ch, char otherCh)
-        {
-            var type = ChunkType.Alphanumeric;
-
-            if (char.IsDigit(otherCh))
-            {
-                type = ChunkType.Numeric;
-            }
-
-            if ((type == ChunkType.Alphanumeric && char.IsDigit(ch))
-                || (type == ChunkType.Numeric && !char.IsDigit(ch)))
-            {
-                return false;
-            }
-
-            return true;
-        }
-    }
-}