[Fix] support latest spdlog (open-mmlab#423)

* support formatting `PixelFormat` & `DataType`

* format enum for legacy spdlog

* fix format

csrc/core/utils/formatter.h

@@ -3,7 +3,11 @@
 #ifndef MMDEPLOY_SRC_UTILS_FORMATTER_H_
 #define MMDEPLOY_SRC_UTILS_FORMATTER_H_
 
+#include <ostream>
+
 #include "core/logger.h"
+#include "core/types.h"
+#include "spdlog/fmt/ostr.h"
 
 #if FMT_VERSION >= 50000
 #include "spdlog/fmt/bundled/ranges.h"
@@ -17,12 +21,55 @@ class Value;
 
 MMDEPLOY_API std::string format_value(const Value& value);
 
+inline std::string to_string(PixelFormat format) {
+  switch (format) {
+    case PixelFormat::kBGR:
+      return "BGR";
+    case PixelFormat::kRGB:
+      return "RGB";
+    case PixelFormat::kGRAYSCALE:
+      return "GRAYSCALE";
+    case PixelFormat::kNV12:
+      return "NV12";
+    case PixelFormat::kNV21:
+      return "NV21";
+    case PixelFormat::kBGRA:
+      return "BGRA";
+    default:
+      return "invalid_format_enum";
+  }
+}
+
+inline std::string to_string(DataType type) {
+  switch (type) {
+    case DataType::kFLOAT:
+      return "FLOAT";
+    case DataType::kHALF:
+      return "HALF";
+    case DataType::kINT8:
+      return "INT8";
+    case DataType::kINT32:
+      return "INT32";
+    case DataType::kINT64:
+      return "INT64";
+    default:
+      return "invalid_data_type_enum";
+  }
+}
+
+inline std::ostream& operator<<(std::ostream& os, PixelFormat format) {
+  return os << to_string(format);
+}
+
+inline std::ostream& operator<<(std::ostream& os, DataType type) { return os << to_string(type); }
+
 }  // namespace mmdeploy
 
 namespace fmt {
 
 #if FMT_VERSION >= 50000
 
+// `Value` maybe an incomplete type at this point, making `operator<<` not usable
 template <>
 struct formatter<mmdeploy::Value> {
   constexpr auto parse(format_parse_context& ctx) { return ctx.begin(); }
@@ -34,21 +81,16 @@ struct formatter<mmdeploy::Value> {
 
 #else
 
-inline void format_arg(BasicFormatter<char> &f, const char *, const mmdeploy::Value &d) {
+inline void format_arg(BasicFormatter<char>& f, const char*, const mmdeploy::Value& d) {
   f.writer() << mmdeploy::format_value(d);
 }
 
-template <typename T, std::enable_if_t<std::is_enum<std::decay_t<T> >::value, bool> = true>
-void format_arg(BasicFormatter<char> &f, const char *, const T &v) {
-  f.writer() << (int)v;
-}
-
 template <typename T>
-auto format_arg(BasicFormatter<char> &f, const char *, const T &v)
+auto format_arg(BasicFormatter<char>& f, const char*, const T& v)
     -> std::void_t<decltype(begin(v), end(v))> {
   f.writer() << "[";
   bool first = true;
-  for (const auto &x : v) {
+  for (const auto& x : v) {
     f.writer() << (first ? "" : ", ") << fmt::format("{}", x);
     first = false;
   }