diff --git a/src/utils/utils.h b/src/utils/utils.h
index 9f13365..42115f2 100644
--- a/src/utils/utils.h
+++ b/src/utils/utils.h
@@ -19,8 +19,9 @@
 #include <unordered_map>
 #include <unordered_set>
 #include <vector>
-#include "options.h"
+#include <limits>
 
+#include "options.h"
 #include "miniz/miniz.h"
 
 /**
@@ -201,15 +202,22 @@ inline bool parse_boolstring(const std::string &value) { return value == "true";
 
 inline double double_min() { return std::numeric_limits<double>::min(); }
 
-static inline std::string &ltrim(std::string &s) {
-  s.erase(s.begin(), std::find_if(s.begin(), s.end(), std::not1(std::ptr_fun<int, int>(std::isspace))));
-  return s;
+// trim from start
+static inline std::string& ltrim(std::string &s)
+{
+    s.erase(s.begin(), std::find_if(s.begin(), s.end(), [](unsigned char ch)
+                                    { return !std::isspace(ch); }));
+    return s;
 }
 
 // trim from end
-static inline std::string &rtrim(std::string &s) {
-  s.erase(std::find_if(s.rbegin(), s.rend(), std::not1(std::ptr_fun<int, int>(std::isspace))).base(), s.end());
-  return s;
+static inline std::string& rtrim(std::string &s)
+{
+    s.erase(std::find_if(s.rbegin(), s.rend(), [](unsigned char ch)
+                         { return !std::isspace(ch); })
+                .base(),
+            s.end());
+    return s;
 }
 
 // trim from both ends