Optimize StringSlice helpers

xoofx · Apr 4, 2020 · f0830b3 · f0830b3
1 parent 1e68149
commit f0830b3
Showing 1 changed file with 46 additions and 46 deletions.
diff --git a/src/Markdig/Helpers/StringSlice.cs b/src/Markdig/Helpers/StringSlice.cs
@@ -51,12 +51,12 @@ public StringSlice(string text, int start, int end)
         /// <summary>
         /// Gets or sets the start position within <see cref="Text"/>.
         /// </summary>
-        public int Start { get; set; }
+        public int Start { readonly get; set; }
 
         /// <summary>
         /// Gets or sets the end position (inclusive) within <see cref="Text"/>.
         /// </summary>
-        public int End { get; set; }
+        public int End { readonly get; set; }
 
         /// <summary>
         /// Gets the length.
@@ -275,13 +275,7 @@ public readonly int IndexOf(string text, int offset = 0, bool ignoreCase = false
             if (length <= 0)
                 return -1;
 
-#if NETCORE
-            var span = Text.AsSpan(offset, length);
-            int index = ignoreCase ? span.IndexOf(text, StringComparison.OrdinalIgnoreCase) : span.IndexOf(text);
-            return index == -1 ? index : index + offset;
-#else
             return Text.IndexOf(text, offset, length, ignoreCase ? StringComparison.OrdinalIgnoreCase : StringComparison.Ordinal);
-#endif
         }
 
         /// <summary>
@@ -296,12 +290,7 @@ public readonly int IndexOf(char c)
             if (length <= 0)
                 return -1;
 
-#if NETCORE
-            int index = Text.AsSpan(start, length).IndexOf(c);
-            return index == -1 ? index : index + start;
-#else
             return Text.IndexOf(c, start, length);
-#endif
         }
 
         /// <summary>
@@ -312,16 +301,15 @@ public readonly int IndexOf(char c)
         /// </returns>
         public bool TrimStart()
         {
-            // Strip leading spaces
-            for (; Start <= End; Start++)
-            {
-                if (Start < Text.Length
-                    && !Text[Start].IsWhitespace())
-                {
-                    break;
-                }
-            }
-            return IsEmpty;
+            string text = Text;
+            int end = End;
+            int i = Start;
+
+            while (i <= end && (uint)i < (uint)text.Length && text[i].IsWhitespace())
+                i++;
+
+            Start = i;
+            return i > end;
         }
 
         /// <summary>
@@ -330,16 +318,15 @@ public bool TrimStart()
         /// <param name="spaceCount">The number of spaces trimmed.</param>
         public void TrimStart(out int spaceCount)
         {
-            spaceCount = 0;
-            // Strip leading spaces
-            for (; Start <= End; Start++)
-            {
-                if (!Text[Start].IsWhitespace())
-                {
-                    break;
-                }
-                spaceCount++;
-            }
+            string text = Text;
+            int end = End;
+            int i = Start;
+
+            while (i <= end && (uint)i < (uint)text.Length && text[i].IsWhitespace())
+                i++;
+
+            spaceCount = i - Start;
+            Start = i;
         }
 
         /// <summary>
@@ -348,24 +335,34 @@ public void TrimStart(out int spaceCount)
         /// <returns></returns>
         public bool TrimEnd()
         {
-            for (; Start <= End; End--)
-            {
-                if (End < Text.Length
-                   && !Text[End].IsWhitespace())
-                {
-                    break;
-                }
-            }
-            return IsEmpty;
+            string text = Text;
+            int start = Start;
+            int i = End;
+
+            while (start <= i && (uint)i < (uint)text.Length && text[i].IsWhitespace())
+                i--;
+
+            End = i;
+            return start > i;
         }
 
         /// <summary>
         /// Trims whitespaces from both the start and end of this slice.
         /// </summary>
         public void Trim()
         {
-            TrimStart();
-            TrimEnd();
+            string text = Text;
+            int start = Start;
+            int end = End;
+
+            while (start <= end && (uint)start < (uint)text.Length && text[start].IsWhitespace())
+                start++;
+
+            while (start <= end && (uint)end < (uint)text.Length && text[end].IsWhitespace())
+                end--;
+
+            Start = start;
+            End = end;
         }
 
         /// <summary>
@@ -393,9 +390,12 @@ public readonly override string ToString()
         /// <returns><c>true</c> if this slice is empty or made only of whitespaces; <c>false</c> otherwise</returns>
         public readonly bool IsEmptyOrWhitespace()
         {
-            for (int i = Start; i <= End; i++)
+            string text = Text;
+            int end = End;
+
+            for (int i = Start; i <= end && (uint)i < (uint)text.Length; i++)
             {
-                if (!Text[i].IsWhitespace())
+                if (!text[i].IsWhitespace())
                 {
                     return false;
                 }