1 files changed, 90 insertions, 0 deletions
diff --git a/src/Jellyfin.Extensions/StringExtensions.cs b/src/Jellyfin.Extensions/StringExtensions.cs
new file mode 100644
index 000000000..fd8f7e59a
--- /dev/null
+++ b/src/Jellyfin.Extensions/StringExtensions.cs
@@ -0,0 +1,90 @@
+using System;
+using System.Text.RegularExpressions;
+
+namespace Jellyfin.Extensions
+{
+    /// <summary>
+    /// Provides extensions methods for <see cref="string" />.
+    /// </summary>
+    public static partial class StringExtensions
+    {
+        // Matches non-conforming unicode chars
+        // https://mnaoumov.wordpress.com/2014/06/14/stripping-invalid-characters-from-utf-16-strings/
+
+        [GeneratedRegex("([\ud800-\udbff](?![\udc00-\udfff]))|((?<![\ud800-\udbff])[\udc00-\udfff])|(�)")]
+        private static partial Regex NonConformingUnicodeRegex();
+
+        /// <summary>
+        /// Removes the diacritics character from the strings.
+        /// </summary>
+        /// <param name="text">The string to act on.</param>
+        /// <returns>The string without diacritics character.</returns>
+        public static string RemoveDiacritics(this string text)
+            => Diacritics.Extensions.StringExtensions.RemoveDiacritics(
+                NonConformingUnicodeRegex().Replace(text, string.Empty));
+
+        /// <summary>
+        /// Checks whether or not the specified string has diacritics in it.
+        /// </summary>
+        /// <param name="text">The string to check.</param>
+        /// <returns>True if the string has diacritics, false otherwise.</returns>
+        public static bool HasDiacritics(this string text)
+            => Diacritics.Extensions.StringExtensions.HasDiacritics(text)
+                || NonConformingUnicodeRegex().IsMatch(text);
+
+        /// <summary>
+        /// Counts the number of occurrences of [needle] in the string.
+        /// </summary>
+        /// <param name="value">The haystack to search in.</param>
+        /// <param name="needle">The character to search for.</param>
+        /// <returns>The number of occurrences of the [needle] character.</returns>
+        public static int Count(this ReadOnlySpan<char> value, char needle)
+        {
+            var count = 0;
+            var length = value.Length;
+            for (var i = 0; i < length; i++)
+            {
+                if (value[i] == needle)
+                {
+                    count++;
+                }
+            }
+
+            return count;
+        }
+
+        /// <summary>
+        /// Returns the part on the left of the <c>needle</c>.
+        /// </summary>
+        /// <param name="haystack">The string to seek.</param>
+        /// <param name="needle">The needle to find.</param>
+        /// <returns>The part left of the <paramref name="needle" />.</returns>
+        public static ReadOnlySpan<char> LeftPart(this ReadOnlySpan<char> haystack, char needle)
+        {
+            var pos = haystack.IndexOf(needle);
+            return pos == -1 ? haystack : haystack[..pos];
+        }
+
+        /// <summary>
+        /// Returns the part on the right of the <c>needle</c>.
+        /// </summary>
+        /// <param name="haystack">The string to seek.</param>
+        /// <param name="needle">The needle to find.</param>
+        /// <returns>The part right of the <paramref name="needle" />.</returns>
+        public static ReadOnlySpan<char> RightPart(this ReadOnlySpan<char> haystack, char needle)
+        {
+            var pos = haystack.LastIndexOf(needle);
+            if (pos == -1)
+            {
+                return haystack;
+            }
+
+            if (pos == haystack.Length - 1)
+            {
+                return ReadOnlySpan<char>.Empty;
+            }
+
+            return haystack[(pos + 1)..];
+        }
+    }
+}