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#include <iostream>
#include <iterator>
#include <vector>
#include <memory>
/* Compiler dependent. Certain compilers may inline operator new, in that
case this will not replace default allocator */
void* operator new(size_t bytes) throw(std::bad_alloc) {
std::cout << "GlobalAlloc(new): " << bytes << std::endl;
return malloc(bytes);
}
//template <typename T> class DSAllocator;
template <typename T>
class DSAllocator : public std::allocator<T> {
public:
typedef size_t size_type;
typedef T* pointer;
template<typename U> struct rebind { typedef DSAllocator<U> other; };
DSAllocator() : std::allocator<T>() {
std::cout << "Constructor " << typeid(T).name() << "()" << std::endl;
}
~DSAllocator() {
std::cout << "Destructor " << typeid(T).name() << "()" << std::endl;
}
DSAllocator(const DSAllocator &a) : std::allocator<T>(a) {
std::cout << "Constructor " << typeid(T).name() << "(a)" << std::endl;
}
template <typename U>
DSAllocator(const DSAllocator<U> &a) : std::allocator<T>(a) {
std::cout << "Constructor " << typeid(T).name() << "(U a)" << std::endl;
}
pointer allocate(size_type cnt, typename std::allocator<void>::const_pointer hint = 0) {
std::cout << "Allocating: " << cnt << '*' << typeid(T).name() << "(" << sizeof(T) << ")" << std::endl;
return std::allocator<T>::allocate(cnt, hint);
}
void deallocate(pointer p, size_type cnt) {
std::cout << "Deallocating: " << cnt << '*' << typeid(T).name() << "(" << sizeof(T) << ")" << std::endl;
return std::allocator<T>::deallocate(p, cnt);
}
void construct(pointer p, const T& val) {
std::cout << "Init" << std::endl;
std::allocator<T>::construct(p, val);
}
void destroy(pointer p) {
std::cout << "Destroy" << std::endl;
std::allocator<T>::destroy(p);
}
};
//template <typename T> class DSAllocator2;
template <typename T>
class DSAllocator2 {
public:
typedef size_t size_type;
typedef ptrdiff_t difference_type;
typedef T* pointer;
typedef const T* const_pointer;
typedef T& reference;
typedef const T& const_reference;
typedef T value_type;
std::allocator<T> *alloc;
template<typename U> struct rebind { typedef DSAllocator2<U> other; };
DSAllocator2() {
std::cout << "Constructor " << typeid(T).name() << "()" << ", " << this << std::endl;
alloc = new std::allocator<T>();
}
~DSAllocator2() {
std::cout << "Destructor " << typeid(T).name() << "()" << ", " << this << std::endl;
delete alloc;
}
/* if this function doesn't exist, everything looks fine, but segmentations
occurs due to the fact, what instead of this constructor simply copy
is running and 'alloc' is freed twice */
DSAllocator2(const DSAllocator2 &a) {
std::cout << "Constructor " << typeid(T).name() << "(a)" << std::endl;
alloc = new std::allocator<T>(*a.alloc);
}
template <typename U> DSAllocator2(const std::allocator<U> &a) {
std::cout << "Constructor " << typeid(T).name() << "(stdal)" << std::endl;
alloc = new std::allocator<T>(a);
}
pointer allocate(size_type cnt, typename std::allocator<void>::const_pointer hint = 0) {
std::cout << "Allocating: " << cnt << '*' << typeid(T).name() << "(" << sizeof(T) << ")" << std::endl;
return alloc->allocate(cnt, hint);
}
void deallocate(pointer p, size_type cnt) {
std::cout << "Deallocating: " << cnt << '*' << typeid(T).name() << "(" << sizeof(T) << ")" << std::endl;
return alloc->deallocate(p, cnt);
}
void construct(pointer p, const T& val) {
std::cout << "Construct: " << typeid(T).name() << "(" << sizeof(T) << ")" << std::endl;
alloc->construct(p, val);
}
void destroy(pointer p) {
std::cout << "Destroy: " << typeid(T).name() << "(" << sizeof(T) << ")" << std::endl;
alloc->destroy(p);
}
size_type max_size() const throw() {
return alloc->max_size();
}
pointer address(reference r) const {
return &r;
}
const pointer address(const_reference r) const {
return &r;
}
};
template<typename _T1, typename _T2>
inline bool operator==(const DSAllocator2<_T1>& a, const DSAllocator2<_T2>& b) {
std::cout << &a << " == " << &b << std::endl;
return true;
}
template<typename _T1, typename _T2>
inline bool operator!=(const DSAllocator2<_T1>& a, const DSAllocator2<_T2>& b) {
std::cout << &a << " != " << &b << std::endl;
return false;
}
using namespace std;
main() {
typedef basic_string<char, char_traits<char>, DSAllocator<char> > ds_string1;
typedef vector <ds_string1, DSAllocator<ds_string1> > ds_vector1;
typedef basic_string<char, char_traits<char>, DSAllocator2<char> > ds_string;
typedef vector <ds_string, DSAllocator<ds_string> > ds_vector;
cout << "Inherited allocator works in vector, but not in string:" << endl;
ds_vector1 *vec1 = new ds_vector1();
char *c = (char*)malloc(50);
strcpy(c, "xxx");
ds_string1 str(c);
strcpy(c, "zzz");
free(c);
vec1->push_back(str);
delete vec1;
cout << endl;
cout << "New allocator works well:" << endl;
ds_vector vec;
vec.push_back("1");
vec.push_back("xxxxxxxxxx");
}
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