fixed performance regression in endsWith()

firewave · firewave · commit f02a68a6658d · 2023-11-14T16:19:04.000+01:00
diff --git a/simplecpp.cpp b/simplecpp.cpp
@@ -154,7 +154,10 @@ 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
`@@ -154,7 +154,10 @@ static unsigned long long stringToULL(const std::string &s)`
`154`	`154`
`155`	`155`	`static bool endsWith(const std::string &s, const std::string &e)`
`156`	`156`	`{`
`157`		`- return (s.size() >= e.size()) && std::equal(e.rbegin(), e.rend(), s.rbegin());`
	`157`	`+ // TODO: std::equal() is much faster than std::string::compare() in a benchmark`
	`158`	`+ // but in our case it leads to a big performance regression`
	`159`	`+ //return (s.size() >= e.size()) && std::equal(e.rbegin(), e.rend(), s.rbegin());`
	`160`	`+ return (s.size() >= e.size() && s.compare(s.size() - e.size(), e.size(), e) == 0);`
`158`	`161`	`}`
`159`	`162`
`160`	`163`	`static bool sameline(const simplecpp::Token tok1, const simplecpp::Token tok2)`