minor improvements

Author: odygrd

CMakeLists.txt

@@ -254,7 +254,6 @@ set(HEADER_FILES
         include/quill/LogMacros.h
         include/quill/StopWatch.h
         include/quill/StringRef.h
-        include/quill/TriviallyCopyableCodec.h
         include/quill/UserClockSource.h
         include/quill/Utility.h
 )

include/quill/StopWatch.h

@@ -70,16 +70,7 @@ class StopWatch
    */
   [[nodiscard]] std::chrono::duration<double> elapsed() const
   {
-    if constexpr (ClockType == ClockSourceType::Tsc)
-    {
-      return std::chrono::duration<double>(std::chrono::nanoseconds{
-        static_cast<uint64_t>(static_cast<double>(rdtsc() - _start_tp) * _ns_per_tick)});
-    }
-    else
-    {
-      return std::chrono::duration<double>(std::chrono::nanoseconds{
-        detail::get_timestamp_ns<std::chrono::steady_clock>() - _start_tp});
-    }
+    return elapsed_as<std::chrono::duration<double>>();
   }
 
   /**

include/quill/StringRef.h

@@ -34,7 +34,7 @@ class StringRef
 public:
   explicit StringRef(std::string const& str) : _str_view(str) {};
   explicit StringRef(std::string_view str) : _str_view(str) {};
-  explicit StringRef(char const* str) : _str_view(str, strlen(str)) {};
+  explicit StringRef(char const* str) : _str_view(str, str ? strlen(str) : 0) {};
   StringRef(char const* str, size_t size) : _str_view(str, size) {};
 
   QUILL_NODISCARD std::string_view const& get_string_view() const noexcept { return _str_view; }

include/quill/TriviallyCopyableCodec.h

@@ -33,6 +33,7 @@ class UserClockSource
 
   /**
    * Returns time since epoch in nanoseconds
+   * @return The current timestamp in nanoseconds
    */
   QUILL_NODISCARD QUILL_ATTRIBUTE_HOT virtual uint64_t now() const = 0;
 };

include/quill/UserClockSource.h

@@ -26,27 +26,31 @@ namespace utility
  * @return A string containing the hexadecimal representation of the given buffer.
  */
 template <typename T>
-QUILL_NODISCARD std::string to_hex(T* buffer, size_t size) noexcept
+QUILL_NODISCARD std::string to_hex(T const* buffer, size_t size)
 {
   static constexpr char hex_chars[] = "0123456789ABCDEF";
 
+  if (!buffer || size == 0)
+  {
+    return {};
+  }
+
+  // Each byte needs 2 hex chars, and all but the last one need spaces
   std::string hex_string;
-  hex_string.reserve(3 * size);
+  hex_string.reserve(size > 0 ? (3 * size - 1) : 0);
 
   for (size_t i = 0; i < size; ++i)
   {
-    // 00001111 mask
-    static constexpr uint8_t mask = 0x0Fu;
-
-    // add the first four bits
-    hex_string += hex_chars[(buffer[i] >> 4u) & mask];
+    const auto byte = static_cast<uint8_t>(buffer[i]);
 
-    // add the remaining bits
-    hex_string += hex_chars[buffer[i] & mask];
+    // Add the first four bits
+    hex_string += hex_chars[(byte >> 4) & 0x0F];
+    // Add the remaining bits
+    hex_string += hex_chars[byte & 0x0F];
 
+    // Add a space delimiter after all but the last byte
     if (i != (size - 1))
     {
-      // add a space delimiter
       hex_string += ' ';
     }
   }