Display available space on SDCard

lib/hal/HalStorage.cpp

@@ -54,6 +54,9 @@ bool HalStorage::writeFile(const char* path, const String& content) {
 
 bool HalStorage::ensureDirectoryExists(const char* path) { HAL_STORAGE_WRAPPED_CALL(ensureDirectoryExists, path); }
 
+uint64_t HalStorage::sdTotalBytes() const { HAL_STORAGE_WRAPPED_CALL(totalBytes); }
+uint64_t HalStorage::sdUsedBytes() const { HAL_STORAGE_WRAPPED_CALL(usedBytes); }
+
 class HalFile::Impl {
  public:
   Impl(FsFile&& fsFile) : file(std::move(fsFile)) {}

lib/hal/HalStorage.h

@@ -45,6 +45,9 @@ class HalStorage {
   bool openFileForWrite(const char* moduleName, const String& path, HalFile& file);
   bool removeDir(const char* path);
 
+  uint64_t sdTotalBytes() const;
+  uint64_t sdUsedBytes() const;
+
   static HalStorage& getInstance() { return instance; }
 
   class StorageLock;  // private class, used internally