How to use std::copy when class has `unsigned char &operator[]` - c++

Question

I'm using a class called Buffer which has the following operator:
unsigned char &operator[](size_t index)
I'm trying to copy from it like this:
std::copy(buf[96], buf[96 + 32], my_uint32_t);
I think it doesn't work
/usr/include/c++/7/bits/stl_algobase.h: In instantiation of '_OI std::__copy_move_a(_II, _II, _OI) [with bool _IsMove = false; _II = unsigned char; _OI = unsigned int]':
/usr/include/c++/7/bits/stl_algobase.h:422:45: required from '_OI std::__copy_move_a2(_II, _II, _OI) [with bool _IsMove = false; _II = unsigned char; _OI = unsigned int]'
/usr/include/c++/7/bits/stl_algobase.h:455:8: required from '_OI std::copy(_II, _II, _OI) [with _II = unsigned char; _OI = unsigned int]'
/home/project/SimplePacketCrafter.h:36:95: required from here
/usr/include/c++/7/bits/stl_algobase.h:377:57: error: no type named 'value_type' in 'struct std::iterator_traits<unsigned char>'
typedef typename iterator_traits<_II>::value_type _ValueTypeI;
^~~~~~~~~~~
/usr/include/c++/7/bits/stl_algobase.h:378:57: error: no type named 'value_type' in 'struct std::iterator_traits<unsigned int>'
typedef typename iterator_traits<_OI>::value_type _ValueTypeO;
^~~~~~~~~~~
/usr/include/c++/7/bits/stl_algobase.h:379:64: error: no type named 'iterator_category' in 'struct std::iterator_traits<unsigned char>'
typedef typename iterator_traits<_II>::iterator_category _Category;
^~~~~~~~~
/usr/include/c++/7/bits/stl_algobase.h:383:9: error: no type named 'value_type' in 'struct std::iterator_traits<unsigned char>'
const bool __simple = (__is_trivial(_ValueTypeI)
~~~~~~~~~~~~~~~~~~~~~~~~~~
&& __is_pointer<_II>::__value
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
&& __is_pointer<_OI>::__value
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
&& __are_same<_ValueTypeI, _ValueTypeO>::__value);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/7/bits/stl_algobase.h:386:44: error: no type named 'iterator_category' in 'struct std::iterator_traits<unsigned char>'
return std::__copy_move<_IsMove, __simple,
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
_Category>::__copy_m(__first, __last, __result);
because I think I'm supposed to pass an address in the first two. There's also
unsigned char *index(size_t index)
but it also doesn't work
The methods can be seen here

Answer 1

std:copy() takes iterators, not references. That is why you are getting an error.
Raw pointers can be used as iterators, provided the elements being pointed to are stored sequentially in memory. So, assuming the buffer's operator[] returns a reference to elements in a single memory buffer, you can use the & address operator to get the memory addresses of the chars being referred to by operator[], and then std::copy() can iterate between those two addresses:
std::copy(&buf[96], &buf[96 + 32], my_uint32_t);
Alternatively, the buffer's index() and c_index() methods return equivilent pointers:
std::copy(buf.index(96), buf.index(96 + 32), my_uint32_t);
std::copy(buf.c_index(96), buf.c_index(96 + 32), my_uint32_t);