Move non-jellyfin extensions to separate project

1 files changed, 144 insertions, 0 deletions

diff --git a/src/Jellyfin.Extensions/AlphanumericComparator.cs b/src/Jellyfin.Extensions/AlphanumericComparator.cs
new file mode 100644
index 000000000..e3c81eba8
--- /dev/null
+++ b/src/Jellyfin.Extensions/AlphanumericComparator.cs
@@ -0,0 +1,144 @@
+using System;
+using System.Collections.Generic;
+
+namespace Jellyfin.Extensions
+{
+    /// <summary>
+    /// Alphanumeric <see cref="IComparer{T}" />.
+    /// </summary>
+    public class AlphanumericComparator : IComparer<string?>
+    {
+        /// <summary>
+        /// Compares two objects and returns a value indicating whether one is less than, equal to, or greater than the other.
+        /// </summary>
+        /// <param name="s1">The first object to compare.</param>
+        /// <param name="s2">The second object to compare.</param>
+        /// <returns>A signed integer that indicates the relative values of <c>x</c> and <c>y</c>.</returns>
+        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;
+                    }
+                }
+#pragma warning disable SA1500 // TODO remove with StyleCop.Analyzers v1.2.0 https://github.com/DotNetAnalyzers/StyleCopAnalyzers/pull/3196
+            } while (pos1 < len1 && pos2 < len2);
+#pragma warning restore SA1500
+
+            return len1 - len2;
+        }
+
+        /// <inheritdoc />
+        public int Compare(string? x, string? y)
+        {
+            return CompareValues(x, y);
+        }
+    }
+}