Implement Span<char>.CountOccurrencesOf()

Author: mythz

src/ServiceStack.Text/StringExtensions.cs

@@ -1220,18 +1220,8 @@ public static IEnumerable<string> ReadLines(this string text)
             }
         }
 
-        public static int CountOccurrencesOf(this string text, char needle)
-        {
-            var chars = text.ToCharArray();
-            var count = 0;
-            var length = chars.Length;
-            for (var n = length - 1; n >= 0; n--)
-            {
-                if (chars[n] == needle)
-                    count++;
-            }
-            return count;
-        }
+        public static int CountOccurrencesOf(this string text, char needle) =>
+            text.AsSpan().CountOccurrencesOf(needle);
 
         public static string NormalizeNewLines(this string text)
         {

src/ServiceStack.Text/StringSpanExtensions.cs

@@ -643,6 +643,19 @@ public static List<string> ToStringList(this IEnumerable<ReadOnlyMemory<char>> f
                 }
             }
             return to;
-        }        
+        }
+        
+        public static int CountOccurrencesOf(this ReadOnlySpan<char> value, char needle)
+        {
+            var count = 0;
+            var length = value.Length;
+            for (var n = length - 1; n >= 0; n--)
+            {
+                if (value[n] == needle)
+                    count++;
+            }
+            return count;
+        }
+
     }
 }