[utils] Add getRealpath function

Since the realpath function is not available in the Windows operating system, the getRealpath function has been added and replaced so that it can be used in the Windows operating system.

- Add getRealpath function to utils.

**Self evaluation:**
1. Build test: [x]Passed []Failed []Skipped
2. Run test: [x]Passed []Failed []Skipped

Signed-off-by: Seungbaek Hong <sb92.hong@samsung.net>

nntrainer/app_context.cpp

@@ -393,7 +393,7 @@ void AppContext::setWorkingDirectory(const std::string &base) {
   }
   closedir(dir);
 
-  char *ret = realpath(base.c_str(), nullptr);
+  char *ret = getRealpath(base.c_str(), nullptr);
 
   if (ret == nullptr) {
     std::stringstream ss;

nntrainer/models/model_loader.cpp

@@ -470,7 +470,7 @@ int ModelLoader::loadFromConfig(std::string config, NeuralNetwork &model) {
 
   model_file_context = std::make_unique<AppContext>();
 
-  auto config_realpath_char = realpath(config.c_str(), nullptr);
+  auto config_realpath_char = getRealpath(config.c_str(), nullptr);
   if (config_realpath_char == nullptr) {
     ml_loge("failed to resolve config path to absolute path, reason: %s",
             strerror(errno));

nntrainer/utils/util_func.cpp

@@ -197,4 +197,12 @@ bool istrequal(const std::string &a, const std::string &b) {
   });
 }
 
+char *getRealpath(const char *__restrict __name, char *__restrict __resolved) {
+#ifdef _WIN32
+  return _fullpath(__resolved, __name, MAX_PATH_LENGTH);
+#else
+  return realpath(__name, __resolved);
+#endif
+}
+
 } // namespace nntrainer

nntrainer/utils/util_func.h

@@ -23,6 +23,10 @@
 #ifndef __UTIL_FUNC_H__
 #define __UTIL_FUNC_H__
 
+#ifdef _WIN32
+#define MAX_PATH_LENGTH 1024
+#endif
+
 #ifdef __cplusplus
 
 #include <cstring>
@@ -271,6 +275,16 @@ template <typename T, typename C = int> T enum_class_or(T e1, T e2) {
   return static_cast<T>(i1 | i2);
 }
 
+/**
+ * @brief Convert a relative path into an absolute path.
+ *
+ * @param __name relative path
+ * @param __resolved variable to store the result value.
+ *
+ * @return absolute path
+ */
+char *getRealpath(const char *__restrict __name, char *__restrict __resolved);
+
 } /* namespace nntrainer */
 
 #endif /* __cplusplus */