Micro-optimize IsMatch::CompareIgnoreCase

dotnet · Feb 12, 2021 · f3cf715 · f3cf715
1 parent 6efb3d1
commit f3cf715
Showing 1 changed file with 6 additions and 4 deletions.
diff --git a/src/Shared/FileMatcher.cs b/src/Shared/FileMatcher.cs
@@ -1672,13 +1672,15 @@ bool CompareIgnoreCase(char inputChar, char patternChar, int iIndex, int pIndex)
                 // We will mostly be comparing ASCII characters, check this first
                 if (inputChar < 128 && patternChar < 128)
                 {
-                    if (inputChar >= 'A' && inputChar <= 'Z' && patternChar >= 'a' && patternChar <= 'z')
+                    if (inputChar >= 'A' && inputChar <= 'Z')
                     {
-                        return inputChar + 32 == patternChar;
+                        // Evaluates to true if patternChar is equal to inputChar or to the lower-case counter-part.
+                        return inputChar == (patternChar & ~0x20);
                     }
-                    if (inputChar >= 'a' && inputChar <= 'z' && patternChar >= 'A' && patternChar <= 'Z')
+                    if (inputChar >= 'a' && inputChar <= 'z')
                     {
-                        return inputChar == patternChar + 32;
+                        // Evaluates to true if patternChar is equal to inputChar or to the upper-case counter-part.
+                        return inputChar == (patternChar | 0x20);
                     }
                     return inputChar == patternChar;
                 }