Optimize Boundary Check in BinarySearch Method

sami-daniel · gfoidl · web-flow · commit eb68105298e9 · 2024-09-25T20:30:33.000-03:00
This commit enhances the performance of the BinarySearch method by eliminating unnecessary boundary checks. The condition if ((uint)candidate.Length &gt; (uint)prefix.Length) ensures that the index access candidate[prefix.Length] is safe, and the JIT compiler can now safely elide the boundary check, improving execution efficiency.

Co-authored-by: Günther Foidl &lt;gue@korporal.at&gt;
diff --git a/src/Mvc/Mvc.Core/src/ModelBinding/PrefixContainer.cs b/src/Mvc/Mvc.Core/src/ModelBinding/PrefixContainer.cs
@@ -212,7 +212,7 @@ private int BinarySearch(string prefix)
                 // which should not qualify as a prefix match. Therefore, we will continue searching
                 // for valid matches in this case.
 
-                if (candidate.Length > prefix.Length)
+                if ((uint)candidate.Length > (uint)prefix.Length)
                 {
                     var c = candidate[prefix.Length];
                     if (c == '.' || c == '[')

Original file line number	Diff line number	Diff line change
`@@ -212,7 +212,7 @@ private int BinarySearch(string prefix)`
`212`	`212`	`// which should not qualify as a prefix match. Therefore, we will continue searching`
`213`	`213`	`// for valid matches in this case.`
`214`	`214`
`215`		`- if (candidate.Length > prefix.Length)`
	`215`	`+ if ((uint)candidate.Length > (uint)prefix.Length)`
`216`	`216`	`{`
`217`	`217`	`var c = candidate[prefix.Length];`
`218`	`218`	`if (c == '.' \|\| c == '[')`