use cppformat in sinks

include/spdlog/sinks/file_sinks.h

@@ -28,8 +28,7 @@
 #include "base_sink.h"
 #include "../details/null_mutex.h"
 #include "../details/file_helper.h"
-#include "../details/fast_oss.h"
-
+#include "../details/format.h"
 
 
 namespace spdlog
@@ -100,12 +99,12 @@ protected:
 private:
     static std::string calc_filename(const std::string& filename, std::size_t index, const std::string& extension)
     {
-        details::fast_oss oss;
+        fmt::MemoryWriter w;
         if (index)
-            oss << filename << "." << index << "." << extension;
+            w.write("{}.{}.{}", filename, index, extension);
         else
-            oss << filename << "." << extension;
-        return oss.str();
+            w.write("{}.{}", filename, extension);
+        return w.str();
     }
 
 
@@ -197,11 +196,9 @@ private:
     static std::string calc_filename(const std::string& basename, const std::string& extension)
     {
         std::tm tm = spdlog::details::os::localtime();
-        details::fast_oss oss;
-        oss << basename << '.';
-        oss << tm.tm_year + 1900 << '-' << std::setw(2) << std::setfill('0') << tm.tm_mon + 1 << '-' << tm.tm_mday;
-        oss << '.' << extension;
-        return oss.str();
+        fmt::MemoryWriter w;
+        w.write("{}.{:04d}-{:02d}-{:02d}.{}", basename, tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, extension);
+        return w.str();
     }
 
     std::string _base_filename;

include/spdlog/sinks/ostream_sink.h

@@ -47,8 +47,7 @@ public:
 protected:
     virtual void _sink_it(const details::log_msg& msg) override
     {
-        auto& buf = msg.formatted.buf();
-        _ostream.write(buf.data(), buf.size());
+        _ostream.write(msg.formatted.data(), msg.formatted.size());
     }
     std::ostream& _ostream;
 };