add format() in StringTools

BaseLib/StringTools.cpp

@@ -16,10 +16,11 @@
 
 #include <algorithm>
 #include <cctype>
+#include <cstdarg>
+#include <cstdio>
 #include <iomanip>
 
-#include "logog/include/logog.hpp"
-
+#include <logog/include/logog.hpp>
 #include <boost/algorithm/string/replace.hpp>
 
 namespace BaseLib
@@ -77,6 +78,23 @@ std::string const& tostring(std::string const& value)
     return value;
 }
 
+std::string format(const char* format_str, ... )
+{
+    va_list args;
+    va_start(args, format_str);
+    // get the number of chars to write
+    va_list args_tmp;
+    va_copy(args_tmp, args);
+    int char_length = std::vsnprintf(nullptr, 0, format_str, args_tmp);
+    va_end(args_tmp);
+    // allocate buffer and store formatted output there
+    std::vector<char> buffer(char_length + 1); // note +1 for null terminator
+    vsnprintf(buffer.data(), buffer.size(), format_str, args);
+    va_end(args);
+
+    return std::string(buffer.data());
+}
+
 } // end namespace BaseLib
 
 #ifdef MSVC

BaseLib/StringTools.h

@@ -79,6 +79,9 @@ template<typename T> std::string tostring(T const& value)
 //! \overload
 std::string const& tostring(std::string const& value);
 
+//! returns printf-like formatted string
+std::string format(const char* format_string, ... );
+
 } // end namespace BaseLib
 
 #ifdef MSVC