I am writing my own stdc/stdc++ libraries as an exercise. I have support for usermode and I have been running binary format code with no problems.
The problem arises when I started adding more template classes in my stdc++ library. I am expanding the std:vector to support a hierarchy with a vector base class and a numbert of specialization templates for different primitive types, e.g. double, float, int, ... etc.
Code: Select all
template<typename T>
class basic_vector {
protected:
T *t;
size_t vec_alloc;
size_t vec_capacity;
size_t vec_size;
public:
typedef std::iterator<bidirectional_iterator_tag, T> iterator;
typedef std::iterator<bidirectional_iterator_tag, const T> const_iterator;
typedef size_t size_type;
basic_vector();
basic_vector(size_type n);
virtual void resize(size_type n);
virtual void resize(size_type n, const T &val);
virtual iterator begin() noexcept;
virtual const_iterator begin() const noexcept;
virtual iterator end() noexcept;
virtual const_iterator end() const noexcept;
virtual T &back();
virtual T &front();
virtual bool empty();
virtual void clear();
virtual T &operator[](size_type index);
virtual const T &operator[](size_type index) const;
virtual void push_back(const T &val);
virtual void push_back(T &&val);
virtual size_t size() const noexcept;
virtual size_t capacity() const noexcept;
virtual void assign(iterator first, iterator last);
virtual void assign(std::string::const_iterator first, std::string::const_iterator last);
virtual void assign(size_type n, const T &val);
virtual void swap(basic_vector &x);
virtual ~basic_vector();
};
template<typename T>
class vector: public basic_vector<T> {
public:
typedef std::iterator<bidirectional_iterator_tag, T> iterator;
typedef std::iterator<bidirectional_iterator_tag, const T> const_iterator;
typedef size_t size_type;
vector();
vector(size_type n);
void resize(size_type n);
void resize(size_type n, const T &val);
void clear();
~vector();
};
template<>
class vector <float>: public basic_vector<float> {
public:
typedef std::iterator<bidirectional_iterator_tag, float> iterator;
typedef std::iterator<bidirectional_iterator_tag, const float> const_iterator;
typedef size_t size_type;
vector();
vector(size_type n);
~vector();
};
template<>
class vector <int>: public basic_vector<int> {
public:
typedef std::iterator<bidirectional_iterator_tag, int> iterator;
typedef std::iterator<bidirectional_iterator_tag, const int> const_iterator;
typedef size_t size_type;
vector();
vector(size_type n);
~vector();
};
template<>
class vector <int *>: public basic_vector<int *> {
public:
typedef std::iterator<bidirectional_iterator_tag, int *> iterator;
typedef std::iterator<bidirectional_iterator_tag, const int *> const_iterator;
typedef size_t size_type;
vector();
vector(size_type n);
~vector();
};
template<>
class vector <double>: public basic_vector<double> {
public:
typedef std::iterator<bidirectional_iterator_tag, double> iterator;
typedef std::iterator<bidirectional_iterator_tag, const double> const_iterator;
typedef size_t size_type;
vector();
vector(size_type n);
~vector();
};
template<>
class vector <char>: public basic_vector<char> {
public:
typedef std::iterator<bidirectional_iterator_tag, char> iterator;
typedef std::iterator<bidirectional_iterator_tag, const char> const_iterator;
typedef size_t size_type;
vector();
vector(size_type n);
~vector();
};
template<>
class vector <unsigned char>: public basic_vector<unsigned char> {
public:
typedef std::iterator<bidirectional_iterator_tag, unsigned char> iterator;
typedef std::iterator<bidirectional_iterator_tag, const unsigned char> const_iterator;
typedef size_t size_type;
vector();
vector(size_type n);
~vector();
};
The problem appears at random where in some random places in the code while running inside some function execution is transferred to address 0x0 and the function never returns causing a page fault.
For example I use a local variable object inside a function vector <float> f; when the specialization class template is defined the problem occurs, when I comment out the specialization template the code works. The confusing thing is that with the specialization template enabled as I add some printfs the code runs well and as soon as I comment them out the problem appears?
I am assuming that I might have some corruption in the vtables as the number of classes gets larger.
My questions are:
1. Where exactly is the vtable stored? in which section?
2. How can I make sure to enlarge the space for it ?
3. Is there anything needs to be done in the linker file?
Any ideas what it could be and how to solve it?
Thanks,
Karim.