stack_allocator.h

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#ifndef _RHEOLEF_STACK_ALLOCATOR_H
#define _RHEOLEF_STACK_ALLOCATOR_H

#include <memory>
#include <limits>
#include "rheolef/compiler.h"
#include "rheolef/pretty_name.h"

namespace rheolef {

//<begin_verbatim:
template <typename T>
class stack_allocator {
protected:
    struct handler_type; // forward declaration:
public:


    typedef size_t         size_type;
    typedef std::ptrdiff_t difference_type;
    typedef T*             pointer;
    typedef const T*       const_pointer;
    typedef T&             reference;
    typedef const T&       const_reference;
    typedef T              value_type;


    stack_allocator() throw()
      : handler (new handler_type)
    {
    }
    stack_allocator (unsigned char* stack, size_t stack_size) throw()
      : handler (new handler_type (stack, stack_size))
    {
        warning_macro ("stack_allocator cstor");
    }
    stack_allocator (const stack_allocator& sa) throw()
      : handler (sa.handler)
    {
        ++handler->reference_count;
    }
    template <typename U>
    stack_allocator (const stack_allocator<U>& sa) throw()
      : handler ((typename stack_allocator<T>::handler_type*)(sa.handler))
    {
        ++handler->reference_count;
    }
    ~stack_allocator() throw()
    {
        warning_macro ("stack_allocator dstor");
        check_macro (handler != NULL, "unexpected null mem_info");
        if (--handler->reference_count == 0) delete handler;
    }
    template <typename U>
    struct rebind {
        typedef stack_allocator<U> other;
    };


    stack_allocator& operator= (const stack_allocator& sa)
    {
        handler = sa.handler;
        ++handler->reference_count;
        return *this;
    }


    pointer       address (reference r)       const { return &r; } 
    const_pointer address (const_reference c) const { return &c; }
    size_type     max_size() const { return std::numeric_limits<size_t>::max() / sizeof(T); }

// in-place construction/destruction

    void construct (pointer p, const_reference c)
    {
        new( reinterpret_cast<void*>(p) ) T(c);
    }
    void construct (pointer p) { new ( reinterpret_cast<void*>(p) ) T(); }

    void destroy (pointer p)
    {
        (p)->~T();
    }


    pointer allocate (size_type n, const void* = NULL)
    {
        warning_macro ("allocate "<<n<<" type " << typename_macro(T));
        check_macro (handler->stack != NULL, "unexpected null stack");
        void* p = handler->stack + handler->allocated_size;
        handler->allocated_size += n*sizeof(T);

        if (handler->allocated_size + 1 > handler->max_size) {
            warning_macro ("stack is full: throwing...");
            throw std::bad_alloc();
        }
        return pointer (p);
    }
    void deallocate (pointer p, size_type n)
    {
        warning_macro ("deallocate "<<n<<" type "<<typename_macro(T));
    }
    const handler_type* get_handler() const {
        return handler;
    }


protected:
    struct handler_type {
        unsigned char* stack;
        size_t         allocated_size;
        size_t         max_size;
        size_t         reference_count;
        
        handler_type()
          : stack (NULL),
            allocated_size (0),
            max_size (0),
            reference_count (1)
        {
          warning_macro ("stack_allocator::mem_info cstor NULL");
        }
        handler_type (unsigned char* stack1, size_t size1)
          : stack (stack1),
            allocated_size (0),
            max_size (size1),
            reference_count (1)
        {
          warning_macro ("stack_allocator::mem_info cstori: size="<<max_size);
        }
        ~handler_type()
        {
          warning_macro ("stack_allocator::mem_info dstor: size="<<max_size);
        }
    };
    handler_type* handler;
    template <typename U> friend class stack_allocator;
};
template <typename T1>
bool operator==( const stack_allocator<T1>& lhs, const stack_allocator<T1>& rhs) throw()
{
    return lhs.get_handler() == rhs.get_handler();
}
template <typename T1>
bool operator!=( const stack_allocator<T1>& lhs, const stack_allocator<T1>& rhs) throw()
{
    return lhs.get_handler() != rhs.get_handler();
}
//>end_verbatim:

} // namespace rheolef
#endif // STACK_ALLOCATOR_H