U++ forum: Welcome to the forum

Re: moveable question [message #38039 is a reply to message #38005]

Thu, 29 November 2012 06:12

mtdew3q
Messages: 181
Registered: July 2010
Location: Upstate, NY (near Canada)

Experienced Member

Hi-

I think this SimpleVector class is moveable because:
1) No references or pointers are stored to the object itself or to subobjects in the methods of the type, into variables that exist after the method finishes execution.
2) The types that can be moved in memory using memcpy are called moveable.

I think that is good enough. It was very hard for me to try to break the assertion but it is good practice to try out memcpy.
I never did end up breaking that assertion. I took out the Vector from the members.

thanks - jim

#include <Core/Core.h>
#include<iostream>
#include<cstring>

using namespace Upp;
using namespace std;

class SimpleVector: Moveable<SimpleVector>{
int len;
char * iptr;
int a;
int * ptr;

public:
SimpleVector(const char *iptr2);

SimpleVector& operator=( const SimpleVector& rhs );
SimpleVector(const SimpleVector & s1);
~SimpleVector();
char* GetString();
} sv1("");

SimpleVector::SimpleVector(const char *iptr2){
std::cout<<"Entering constructor";
std::cout<<endl;

len = strlen(iptr2) + 1;
iptr = new char[len + 1];
strncpy(iptr, iptr2, len);
iptr[len-1]='/0';
a = 10;
ptr = new int(2);

std::cout<<"leaving constructor";
}
SimpleVector& SimpleVector::operator=( const SimpleVector& rhs ){

Cout()<<"entering assignment";
std::cout<<endl;

if (this == &rhs)
return *this;

std::cout<<"debug test"<<endl;

delete [] iptr;
iptr=0;
len = rhs.len;

delete ptr;
ptr=0;

if(rhs.iptr){
iptr = new char[len + 1];
strncpy(iptr,rhs.iptr,len);
a = rhs.a;
Cout()<<*iptr;
std::cout<<endl;
}else
iptr=0;

if(rhs.ptr){
ptr = new int(2);
memcpy(ptr,rhs.ptr,sizeof(int));
}else
ptr=0;

return *this;
}

SimpleVector::~SimpleVector(){
Cout()<< "the new soundgarden album is out!";
std::cout<<endl;
delete[] iptr;
iptr = 0;

delete ptr;
ptr = 0;
std::cout<<"debug test"<<endl;
AssertMoveable<SimpleVector>();
}

CONSOLE_APP_MAIN
{
std::cout<<endl;
std::cout<<"program begin!";
cout<<endl;
SimpleVector s("foo1");
SimpleVector s2("foo2");
// SimpleVector s2 = s; copy constructor
s2=s;
}

Report message to a moderator