Calculate MD5 of a file in Unreal Engine

unreal_engine_md5.cpp

FString MD5(FString file_name)
{
  std::ifstream file(std::string(TCHAR_TO_UTF8(*file_name)), std::ios::binary);
  if (!file) {
    return FString();
  }

  // Compute the MD5 hash of the file contents
  FMD5 md5;
  char buffer[4096];
  while (file.read(buffer, sizeof(buffer))) {
    md5.Update((const uint8*)buffer, sizeof(buffer));
  }
  md5.Update((const uint8*)buffer, file.gcount());

  uint8 hash[16];
  md5.Final(hash);

  // Convert the hash value to a string of hexadecimal digits
  FString string = FString::Printf(TEXT("%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x"),
    hash[0], hash[1], hash[2], hash[3], hash[4], hash[5], hash[6], hash[7],
    hash[8], hash[9], hash[10], hash[11], hash[12], hash[13], hash[14], hash[15]);

  return string;
}