Use more fmt

llarp/util/str.cpp

@@ -149,45 +149,23 @@ namespace llarp
   std::string
   friendly_duration(std::chrono::nanoseconds dur)
   {
-    std::ostringstream os;
-    bool some = false;
-    if (dur >= 24h)
-    {
-      os << dur / 24h << 'd';
-      dur %= 24h;
-      some = true;
-    }
-    if (dur >= 1h || some)
-    {
-      os << dur / 1h << 'h';
-      dur %= 1h;
-      some = true;
-    }
-    if (dur >= 1min || some)
-    {
-      os << dur / 1min << 'm';
-      dur %= 1min;
-      some = true;
-    }
-    if (some)
-    {
-      // If we have >= minutes then don't bother with fractional seconds
-      os << dur / 1s << 's';
-    }
-    else
-    {
-      double seconds = std::chrono::duration<double>(dur).count();
-      os.precision(3);
-      if (dur >= 1s)
-        os << seconds << "s";
-      else if (dur >= 1ms)
-        os << seconds * 1000 << "ms";
-      else if (dur >= 1us)
-        os << seconds * 1'000'000 << u8"µs";
-      else
-        os << seconds * 1'000'000'000 << "ns";
-    }
-    return os.str();
+    const double dsecs = std::chrono::duration<double>(dur).count();
+    return fmt::format(
+        dur >= 24h        ? "{0}d{1}h{2}m{3}s"
+            : dur >= 1h   ? "{1}h{2}m{3}s"
+            : dur >= 1min ? "{2}m{3}s"
+            : dur >= 1s   ? "{4:.3f}s"
+            : dur >= 1ms  ? "{5:.3f}s"
+            : dur >= 1us  ? u8"{6:.3f}µs"
+                          : "{7}ns",
+        dur / 24h,
+        dur / 1h,
+        dur / 1min,
+        dur / 1s,
+        dsecs,
+        dsecs * 1'000,
+        dsecs * 1'000'000,
+        dur.count());
   }
 
 }  // namespace llarp

llarp/util/str.hpp

@@ -1,12 +1,13 @@
 #pragma once
 
 #include <string_view>
-#include <sstream>
 #include <vector>
 #include <chrono>
 #include <iterator>
 #include <charconv>
 
+#include <fmt/format.h>
+
 namespace llarp
 {
   bool
@@ -96,17 +97,12 @@ namespace llarp
   split_any(std::string_view str, std::string_view delims, bool trim = false);
 
   /// Joins [begin, end) with a delimiter and returns the resulting string.  Elements can be
-  /// anything that can be sent to an ostream via `<<`.
+  /// anything that is fmt formattable.
   template <typename It>
   std::string
   join(std::string_view delimiter, It begin, It end)
   {
-    std::ostringstream o;
-    if (begin != end)
-      o << *begin++;
-    while (begin != end)
-      o << delimiter << *begin++;
-    return o.str();
+    return fmt::format("{}", fmt::join(delimiter, begin, end));
   }
 
   /// Wrapper around the above that takes a container and passes c.begin(), c.end() to the above.

llarp/vpn/win32.hpp

@@ -8,6 +8,8 @@
 #include <llarp/ev/vpn.hpp>
 #include <llarp/router/abstractrouter.hpp>
 
+#include <fmt/std.h>
+
 // DDK macros
 #define CTL_CODE(DeviceType, Function, Method, Access) \
   (((DeviceType) << 16) | ((Access) << 14) | ((Function) << 2) | (Method))
@@ -237,9 +239,7 @@ namespace llarp::vpn
         LogError("cannot query registry");
         throw std::invalid_argument{"cannot query registery"};
       }
-      std::stringstream ss;
-      ss << "\\\\.\\Global\\" << device_id << ".tap";
-      const auto fname = ss.str();
+      const auto fname = fmt::format(R"(\\.\Global\{}.tap)", device_id);
       m_Device = CreateFile(
           fname.c_str(),
           GENERIC_WRITE | GENERIC_READ,
@@ -537,16 +537,8 @@ namespace llarp::vpn
     void
     Route(IPVariant_t ip, IPVariant_t gateway, std::string cmd)
     {
-      std::stringstream ss;
-      std::string ip_str;
-      std::string gateway_str;
-
-      std::visit([&ip_str](auto&& ip) { ip_str = ip.ToString(); }, ip);
-      std::visit([&gateway_str](auto&& gateway) { gateway_str = gateway.ToString(); }, gateway);
-
-      ss << RouteCommand() << " " << cmd << " " << ip_str << " MASK 255.255.255.255 " << gateway_str
-         << " METRIC 2";
-      Execute(ss.str());
+      Execute(fmt::format(
+          "{} {} {} MASK 255.255.255.255 {} METRIC 2", RouteCommand(), cmd, ip, gateway));
     }
 
     void