3.18. C++
call printf_chk
mov eax, [esi+4] ; operator--: get ->prev pointer
mov edx, [eax+0Ch]
mov [esp+0Ch], edx
mov eax, [eax+8]
mov dword ptr [esp+4], offset a1stElementDD ; "1st element: %d %d\n"
mov dword ptr [esp], 1
mov [esp+8], eax
call printf_chk
mov dword ptr [esp], offset aRemovingLastEl ; "removing last element..."
call puts
mov esi, [esp+14h]
mov [esp], esi
call _ZNSt8detail15_List_node_base9_M_unhookEv ; std::detail::_List_node_base::⤦
Ç_M_unhook(void)
mov [esp], esi ; void
call _ZdlPv ; operator delete(void )
mov [esp], ebx
call _Z13dump_List_valPj ; dump_List_val(uint *)
mov [esp], ebx
call _ZNSt10_List_baseI1aSaIS0_EE8_M_clearEv ; std::_List_base<a,std::allocator>::⤦
Ç_M_clear(void)
lea esp, [ebp-8]
xor eax, eax
pop ebx
pop esi
pop ebp
retn
main endp
Listing 3.110: The whole output- empty list:
ptr=0x0028fe90 _Next=0x0028fe90 _Prev=0x0028fe90 x=3 y=0 - 3-elements list:
ptr=0x000349a0 _Next=0x00034988 _Prev=0x0028fe90 x=3 y=4
ptr=0x00034988 _Next=0x00034b40 _Prev=0x000349a0 x=1 y=2
ptr=0x00034b40 _Next=0x0028fe90 _Prev=0x00034988 x=5 y=6
ptr=0x0028fe90 _Next=0x000349a0 _Prev=0x00034b40 x=5 y=6
node at .begin:
ptr=0x000349a0 _Next=0x00034988 _Prev=0x0028fe90 x=3 y=4
node at .end:
ptr=0x0028fe90 _Next=0x000349a0 _Prev=0x00034b40 x=5 y=6 - let's count from the beginning:
1st element: 3 4
2nd element: 1 2
3rd element: 5 6
element at .end(): 5 6 - let's count from the end:
element at .end(): 5 6
3rd element: 5 6
2nd element: 1 2
1st element: 3 4
removing last element...
ptr=0x000349a0 _Next=0x00034988 _Prev=0x0028fe90 x=3 y=4
ptr=0x00034988 _Next=0x0028fe90 _Prev=0x000349a0 x=1 y=2
ptr=0x0028fe90 _Next=0x000349a0 _Prev=0x00034988 x=5 y=6
MSVC
MSVC’s implementation (2012) is just the same, but it also stores the current size of the list.
This implies that the .size() method is very fast (O(1)): it just reads one value from memory.
On the other hand, the size variable must be updated at each insertion/deletion.
MSVC’s implementation is also slightly different in the way it arranges the nodes: