[General Q] Saving and loading a struct

[Bate]

Is that going to work properly in all cases? I'm not quite sure if there might be a problem with casting strings.

Code: Select all

struct SData
{
  std::string a[100];
  std::string b[100][100];
  int c[100];
  float d[100][100];
};

std::string filepath = "test.dat";

void CSaveEngine::saveData(SData data)
{
  std::fstream binFile(filePath.c_str(), std::ios::binary | std::ios::out);
  binFile.write( reinterpret_cast<char*>(&data), sizeof(SData) );
  binFile.close();
}

SData CSaveEngine::loadData()
{
  SData data;

  std::fstream binFile(filePath.c_str(), std::ios::binary | std::ios::in);
  binFile.read( reinterpret_cast<char*>(&data), sizeof(SData) );
  binFile.close();

  return data;
}

[vitek]

That code is not safe at all. Using read and write that way is only safe for plain-old-data types. std::string is not a plain-old-data type.

Travis

[Bate]

So I need multi-dimensional char arrays, right? It works with arrays, though, doesn't it? Or is there a better solution?

Thanks

[vitek]

The better solution would be to write proper code to serialize your object type. It would also be a good idea to use a vector or list instead of fixed length arrays.

[Josie]

Vitek is right, however vague.

Two good places to start with serialization are the wikipedia article and C++ faq lite.

Boost has an excellent serialization library.

[Bate]

Thanks, Boost's serialization looks promising.

[sudi]

That code is not safe at all. Using read and write that way is only safe for plain-old-data types. std::string is not a plain-old-data type.

Travis

Thats just wrong! all std types can be serialized directly like this! works seamles. problem arrises when u start using irrlicht types and pointers which don't serialize at all.