Re: Converting between vectors

I need in short to serialize vector of different types into a stream of
chars, which is then sent over the network.
Boost unfortunately is not the answer since I can't use it in the
project.

Until now I used the function below, but I found out that is terribly
buggy, since it doesn't work in all cases of type conversion and even
size.

But I can't find a way to fix it and to make it general, any idea /hint?

Thanks,
Andrea

#include<assert.h>
#include<string>
#include<cstdlib>
#include<iostream>
#include<vector>

template<typename INP, typename OUT>
std::vector<OUT> vectorConversion(const std::vector<INP>& input)
{
     size_t size_inp = sizeof(INP);
     size_t size_out = sizeof(OUT);
     // make sure the sizeof are multiples between them, otherwise it doesn't work!
     assert(((size_inp % size_out) == 0) || ((size_out % size_inp) == 0));
     std::vector<OUT> res;
     size_t size = (size_inp * input.size()) / size_out;
     res.resize(size);
     // is it memcpy a good idea in this case?
     memcpy(&res[0],&input[0], size_inp * input.size());
     return res;
}

int main()
{
     std::vector<int> vec(5, 1);
     std::vector<long> lvec = vectorConversion<int, long>(vec);
     std::vector<int> vec2 = vectorConversion<long, int>(lvec);

     assert(vec == vec2);
     return 0;
}