Remove filesystem header (#2998)

Author: csukuangfj

sherpa-onnx/csrc/file-utils.cc

@@ -10,6 +10,13 @@
 #include <string>
 #include <vector>
 
+#ifdef _WIN32
+#include <windows.h>
+#else
+#include <limits.h>
+#include <stdlib.h>
+#endif
+
 #include "sherpa-onnx/csrc/macros.h"
 
 namespace sherpa_onnx {
@@ -107,4 +114,38 @@ std::vector<char> ReadFile(NativeResourceManager *mgr,
 }
 #endif
 
+std::string ResolveAbsolutePath(const std::string &path) {
+  if (path.empty()) {
+    return path;
+  }
+
+#ifdef _WIN32
+  // Check if path is already absolute (drive letter or UNC path)
+  if ((path.size() > 1 && path[1] == ':') ||
+      (path.size() > 1 && path[0] == '\\' && path[1] == '\\')) {
+    return path;
+  }
+
+  char buffer[MAX_PATH];
+  if (GetFullPathNameA(path.c_str(), MAX_PATH, buffer, nullptr)) {
+    return std::string(buffer);
+  }
+
+  return path;  // fallback on failure
+
+#else
+  // POSIX: absolute paths start with '/'
+  if (path[0] == '/') {
+    return path;
+  }
+
+  char buffer[PATH_MAX];
+  if (realpath(path.c_str(), buffer)) {
+    return std::string(buffer);
+  }
+
+  return path;  // fallback on failure
+#endif
+}
+
 }  // namespace sherpa_onnx

sherpa-onnx/csrc/file-utils.h

@@ -44,6 +44,8 @@ std::vector<char> ReadFile(NativeResourceManager *mgr,
                            const std::string &filename);
 #endif
 
+std::string ResolveAbsolutePath(const std::string &path);
+
 }  // namespace sherpa_onnx
 
 #endif  // SHERPA_ONNX_CSRC_FILE_UTILS_H_

sherpa-onnx/csrc/offline-funasr-nano-model.cc

@@ -9,7 +9,6 @@
 #include <cmath>
 #include <cstdint>
 #include <cstring>
-#include <filesystem>
 #include <memory>
 #include <sstream>
 #include <string>
@@ -1016,10 +1015,7 @@ class OfflineFunASRNanoModel::Impl {
     bool has_external_data = FileExists(data_path);
 
     // Resolve absolute path for model file
-    std::string abs_model_path = model_path;
-    if (!model_path.empty() && !std::filesystem::path(model_path).is_absolute()) {
-      abs_model_path = std::filesystem::absolute(model_path).string();
-    }
+    std::string abs_model_path = ResolveAbsolutePath(model_path);
 
     if (has_external_data) {
       // When external data exists, use absolute file path to create session.