fixed performance regression in endsWith()

firewave · firewave · commit 39fe3b698056 · 2025-08-29T17:20:22.000+02:00
diff --git a/simplecpp.cpp b/simplecpp.cpp
@@ -138,7 +138,10 @@ static unsigned long long stringToULL(const std::string &s)
 
 static bool endsWith(const std::string &s, const std::string &e)
 {
-    return (s.size() >= e.size()) && std::equal(e.rbegin(), e.rend(), s.rbegin());
+    // TODO: std::equal() is much faster than std::string::compare() in a benchmark
+    // but in our case it leads to a big performance regression
+    //return (s.size() >= e.size()) && std::equal(e.rbegin(), e.rend(), s.rbegin());
+    return (s.size() >= e.size() && s.compare(s.size() - e.size(), e.size(), e) == 0);
 }
 
 static bool sameline(const simplecpp::Token *tok1, const simplecpp::Token *tok2)

Original file line number	Diff line number	Diff line change
`@@ -138,7 +138,10 @@ static unsigned long long stringToULL(const std::string &s)`
`138`	`138`
`139`	`139`	`static bool endsWith(const std::string &s, const std::string &e)`
`140`	`140`	`{`
`141`		`- return (s.size() >= e.size()) && std::equal(e.rbegin(), e.rend(), s.rbegin());`
	`141`	`+ // TODO: std::equal() is much faster than std::string::compare() in a benchmark`
	`142`	`+ // but in our case it leads to a big performance regression`
	`143`	`+ //return (s.size() >= e.size()) && std::equal(e.rbegin(), e.rend(), s.rbegin());`
	`144`	`+ return (s.size() >= e.size() && s.compare(s.size() - e.size(), e.size(), e) == 0);`
`142`	`145`	`}`
`143`	`146`
`144`	`147`	`static bool sameline(const simplecpp::Token tok1, const simplecpp::Token tok2)`