add file system utils

Author: tikikun

utils/nitro_utils.h

@@ -6,9 +6,51 @@
 #include <drogon/HttpResponse.h>
 #include <iostream>
 #include <ostream>
+// Include platform-specific headers
+#ifdef _WIN32
+#include <windows.h>
+#else
+#include <dirent.h>
+#endif
 
 namespace nitro_utils {
 
+inline std::string models_folder = "./models";
+
+inline std::vector<std::string> listFilesInDir(const std::string &path) {
+  std::vector<std::string> files;
+
+#ifdef _WIN32
+  // Windows-specific code
+  WIN32_FIND_DATA findFileData;
+  HANDLE hFind = FindFirstFile((path + "\\*").c_str(), &findFileData);
+
+  if (hFind != INVALID_HANDLE_VALUE) {
+    do {
+      if (!(findFileData.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)) {
+        files.push_back(findFileData.cFileName);
+      }
+    } while (FindNextFile(hFind, &findFileData) != 0);
+    FindClose(hFind);
+  }
+#else
+  // POSIX-specific code (Linux, Unix, MacOS)
+  DIR *dir;
+  struct dirent *ent;
+
+  if ((dir = opendir(path.c_str())) != NULL) {
+    while ((ent = readdir(dir)) != NULL) {
+      if (ent->d_type == DT_REG) { // Check if it's a regular file
+        files.push_back(ent->d_name);
+      }
+    }
+    closedir(dir);
+  }
+#endif
+
+  return files;
+}
+
 inline std::string rtrim(const std::string &str) {
   size_t end = str.find_last_not_of("\n\t ");
   return (end == std::string::npos) ? "" : str.substr(0, end + 1);