Re: [avr-libc-dev] new, delete support

[Ned Konz]

kashey wrote:
> Ned Konz пишет:
> > kashey wrote:
> > > kashey пишет:
> > > > Ned Konz пишет:
> > > > > kashey wrote:
> > > > > > Hi all.
> > > > > > When be included support new and delete functions support in 
> > > > > > avr-libc?
> > > > >
> > > > > What do you need? Assuming you don't need the whole libstdc++ 
> > > > > library, this will probably do what you need for typical C++ programs.
> > > > >
> > > > >
> > > > > extern "C" {
> > > > > #include <stddef.h>
> > > > > #include <stdlib.h>
> > > > > }
> > > > >
> > > > > void *operator
> > > > > new(size_t sz) throw()
> > > > > {
> > > > >   return malloc(sz);
> > > > > }
> > > > >
> > > > > void operator
> > > > > delete(void *p)
> > > > > {
> > > > >     free(p);
> > > > > }
> > > > >
> > > > > extern "C" __cxa_pure_virtual();
> > > > >
> > > > > void __cxa_pure_virtual()
> > > > > {
> > > > >    abort();
> > > > > }
> > > > And what about calling Constructor/Destructor ?
> >
> > What do you mean? That's not the job of avr-libc.
> >
> > Is there some code that you want to write that won't call the 
> > constructor and destructor, given the above?
> >
> > I am using a recent version of avr-gcc (4.2.0, almost) and am using 
> > templates, constructors, destructors, and so on using more or less 
> > just the above and avr-libc.
> >
> > Most of my objects are static, and so the constructors get called 
> > before main() (and the destructors never do), but if there were 
> > actually an exit from my code (nowhere to go, in ROM) the destructors 
> > would also get called.
> It's solution for static objects. If you can describe what i have do if 
> I'll use dynamic object.
>
> As example:
> class KMyClass
> {
>    private:
>       int *Array;
>       int Len;
>    public:
>       KMyClass(int Len)
>       {
>          Len = len;
>           Array = new int [len];
>        }
>       ~KMyClass()
>       {
>          delete [] Array;
>       }
> }
>
> ...
> int main()
> {
>    KMyClass *var = new KMyClass(10);
>    ...
>    return 0;
> }

Something like this (I added set_new_handler()) should work (this is a 
modified version of the libstdc++ code, with all the exception-related 
stuff pulled out):


// avr-gcc -Os -g -Wa,-ahlds=newDelete.lst -fno-exceptions -c newDelete.cpp

extern "C++" {
namespace std
{
  typedef unsigned int size_t;
  typedef void (*new_handler)();
  new_handler set_new_handler(new_handler) throw();
}

void operator delete(void*) throw();
void operator delete[](void*) throw();
void* operator new(std::size_t) throw();
void* operator new[](std::size_t) throw();
void operator delete(void*) throw();
void operator delete[](void*) throw();
// Default placement versions of operator new.
inline void* operator new(std::size_t, void* __p) throw() { return __p; }
inline void* operator new[](std::size_t, void* __p) throw() { return __p; }
// Default placement versions of operator delete.
inline void  operator delete  (void*, void*) throw() { }
inline void  operator delete[](void*, void*) throw() { }
}

// --- implementation ---
//

using std::new_handler;
extern "C" void *malloc (std::size_t);
extern "C" void free(void *);
extern void abort() __attribute__((noreturn));
new_handler __new_handler;

void *
operator new (std::size_t sz) throw()
{
    void *p;
    if (sz == 0)
        sz = 1;
    p = (void*) malloc(sz);

    while (p == 0)
    {
        new_handler handler = __new_handler;
        if (! handler)
            return 0;
        handler();
        p = (void *) malloc(sz);
    }

    return p;
}

void*
operator new[] (std::size_t sz) throw()
{
  return ::operator new(sz);
}

void
operator delete (void *ptr) throw ()
{
  if (ptr)
    free (ptr);
}

void
operator delete[] (void *ptr) throw ()
{
  ::operator delete (ptr);
}

void __cxa_pure_virtual()
{
    abort();
}

class KMyClass
{
   private:
      int *Array;
      int Len;
   public:
      KMyClass(int len) : Len(len), Array(new int[len]) { }
      ~KMyClass() { delete [] Array; }
      int& operator[] (int i) { return Array[i]; }
};

KMyClass *someFunc(int i)
{
   KMyClass *var = new KMyClass(i);
   return var;
}

void someOtherFunc(KMyClass *kmc)
{
    delete kmc;
}



Thanks,
--
Ned Konz
address@hidden
http://bike-nomad.com