Why am I getting an std::bad_alloc error - c++

Question

I'm having an issue when running the code below. Every time I set the while loop to reach the .eof() it returns a std::bad_alloc
inFile.open(fileName, std::ios::in | std::ios::binary);
if (inFile.is_open())
{
while (!inFile.eof())
{
read(inFile, readIn);
vecMenu.push_back(readIn);
menu.push_back(readIn);
//count++;
}
std::cout << "File was loaded succesfully..." << std::endl;
inFile.close();
}
It runs fine if I set a predetermined number of iterations, but fails when I use the EOF funtion. Here's the code for the read function:
void read(std::fstream& file, std::string& str)
{
if (file.is_open())
{
unsigned len;
char *buf = nullptr;
file.read(reinterpret_cast<char *>(&len), sizeof(unsigned));
buf = new char[len + 1];
file.read(buf, len);
buf[len] = '\0';
str = buf;
std::cout << "Test: " << str << std::endl;
delete[] buf;
}
else
{
std::cout << "File was not accessible" << std::endl;
}
}
Any help you can provide is greatly appreciated.
NOTE: I failed to mention that vecMenu is of type std::vector
and menu is of type std::list

Answer 1

The main problems I see are:
You are using while (!inFile.eof()) to end the loop. See Why is iostream::eof inside a loop condition considered wrong?.
You are not checking whether calls to ifstream::read succeeded before using the variables that were read into.
I suggest:
Changing your version of read to return a reference to ifstream. It should return the ifstream it takes as input. That makes it possible to use the call to read in the conditional of a loop.
Checking whether calls to ifstream::read succeed before using them.
Putting the call to read in the conditional of the while statement.
std::ifstream& read(std::fstream& file, std::string& str)
{
if (file.is_open())
{
unsigned len;
char *buf = nullptr;
if !(file.read(reinterpret_cast<char *>(&len), sizeof(unsigned)))
{
return file;
}
buf = new char[len + 1];
if ( !file.read(buf, len) )
{
delete [] buf;
return file;
}
buf[len] = '\0';
str = buf;
std::cout << "Test: " << str << std::endl;
delete[] buf;
}
else
{
std::cout << "File was not accessible" << std::endl;
}
return file;
}
and
inFile.open(fileName, std::ios::in | std::ios::binary);
if (inFile.is_open())
{
std::cout << "File was loaded succesfully..." << std::endl;
while (read(inFile, readIn))
{
vecMenu.push_back(readIn);
menu.push_back(readIn);
//count++;
}
inFile.close();
}