Re: size of a variable

From:

Vlad from Moscow <vlad.moscow@mail.ru>

Newsgroups:

comp.lang.c++

Date:

Mon, 16 Feb 2015 09:05:35 -0800 (PST)

Message-ID:

<dfe4cde0-3bd4-4d0c-9d78-a5a8d5cf174e@googlegroups.com>

I bthink that some structure would be more approproate to this definition.

B0 = Flags || Nonce N || l(m).

For example

struct BaseField
{
    std::uint8_t flags;
    std::uint8_t nonce[14];
    std::uint8_t length;
};

So you could use standard container std::vector specialized for this structure. For example

#include <iostream>
#include <cstdint>
#include <vector>

struct BaseField
{
    std::uint8_t flags;
    std::uint8_t nonce[14];
    std::uint8_t length;
};

int main()
{
    std::vector<BaseField> v;

    return 0;
}
On Monday, February 16, 2015 at 7:41:11 PM UTC+3, ghada glissa wrote:

What i'm supposed to do is

1) Form the 16-octet B0 field consisting of the 1-octet Flags field,the (15-L)-octet Nonce field, and the L-octet representation of the Length field l(m), as follows:

B0 = Flags || Nonce N || l(m).

the next step is:

2)Parse the message AuthData as B1 || B2 || ... ||Bt, where each message block Bi is a 16-octet string.

and the next step is to do some arithmetic operation with all the Bi

So i have many problems:

1. the 16 bytes variable,(may i use pointer to pointer ??)
2. the wrong use of memcpy : memcpy (B[i],AuthData,16);
3. wrong use of the left shift << operator with AuthData : AuthData<<128;

So any help please.

Regards.