Something like this maybe ? I have not tested it much.
Symon
#include <stdio.h>
#include <stdint.h>
#include <string.h>
typedef struct {
uint8_t *pkt1;
uint8_t *pkt2;
uint8_t *pkt3;
uint8_t *pktOut;
uint8_t cmplen;
}cmpPktInfo_t;
uint8_t* pktcmp(cmpPktInfo_t *cpi) {
uint8_t i;
for(i=0; i<cpi->cmplen; i++) {
if(!((cpi->pkt1[i] ^ cpi->pkt2[i]) || (cpi->pkt1[i] ^ cpi->pkt3[i]))) {
cpi->pktOut[i] = cpi->pkt1[i];
}else if(!(cpi->pkt1[i] ^ cpi->pkt2[i])) {
cpi->pktOut[i] = cpi->pkt1[i];
}else if(!(cpi->pkt1[i] ^ cpi->pkt3[i])) {
cpi->pktOut[i] = cpi->pkt1[i];
}else if(!(cpi->pkt2[i] ^ cpi->pkt3[i])) {
cpi->pktOut[i] = cpi->pkt2[i];
}
}
return cpi->pktOut;
}
int main() {
uint8_t answer[6] = {0};
cmpPktInfo_t cpi = {"HELLO", "MaULO", "HELLR", (uint8_t*)&answer,
sizeof(answer)};
printf("pktOut: %s\n", pktcmp(&cpi));
return 0;
}
> Date: Tue, 3 Mar 2009 14:49:37 -0500
> From: [email protected]
> To: [email protected]
> CC: [email protected]
> Subject: Re: [Tinyos-help] compare bit to bit or byte to byte
>
> Hi!
>
> On Tue, 3 Mar 2009, Sonia Pardo wrote:
>
> > Hi,
> >
> > Sorry for my explanation but I think is not clear. Let's try again.
> >
> > I've one mote which send packets in broadcast. On the other side I've three
> > motes that receive the packets from first mote. One mote of them is
> > connected whit the PC (mote B). I've made a programm that show the data
> > content of the received packets in mote B.
> > Maybe mote B receives packets whit errors in data content, then I send a
> > message to the others receiver motes and they send mote B the received
> > packet again. (I guess that packets of this motes can have others errors in
> > data content).
> > Now I've three packets in mote B. I can show the data content of the three
> > packets in my application. I want to compare bit to bit the data content of
> > this three received packets to create a good data content and I only show
> > that in my application.
> >
> > I don't know how to make this comparison bit to bit.
> > I make an example:
> >
> > Transmitter: Send Hello
> > Receiver (mote B): Receive Mello
> > Receiver C: Receive HeUlo
> > Receiver D: Receive HellR
> >
> > I want to compare bit to bit (Mello, HeUlo and HellR) to create the word
> > Hello using majority voting.
>
> I still don't know exactly what you mean by 'bit to bit' but the
> explanations on pages 24-25 from here might be useful:
> http://www.ti.com/lit/gpn/cc2420
> As you can see the bytes are broken into two symbols and each is then
> transmitted as 32 chips. Is this what you were looking for?
>
> --
> Razvan ME
>
> > I hope that you understand my explanation better.
> >
> > Thanks in advanced,
> >
> > Sonia
> >
> > 2009/3/3 Razvan Musaloiu-E. <[email protected]>
> >
> >> Hi!
> >>
> >> On Tue, 3 Mar 2009, Sonia Pardo wrote:
> >>
> >> Dear All,
> >>>
> >>> We can't use memcmp because this function only say us if the packet is the
> >>> same or not.
> >>> We would like to compare bit to bit because I want to rebuild the packet.
> >>>
> >>> For example, we receive three packets from three different motes (But
> >>> three
> >>> motes send the same information). One of them receives Hello. Other mote
> >>> receives Hello too, but the third packet receives Mello. This packet has
> >>> errors, but if I compare the three packets bit to bit, I can rebuild the
> >>> message of the third packet and I can say that the information of this
> >>> packet is Hello too.
> >>>
> >>> I need a function which compare bit to bit, because I don't know how can I
> >>> do this...and I think that memcmp is not valid for this.
> >>>
> >>> Can anyone help us?
> >>>
> >>>
> >> CC2420 and RF230 are packet-based radios so you don't have access to
> >> information about the quality of each bit. CC1000 from mica2 is not
> >> packet-based so what you want should be possible there.
> >>
> >> --
> >> Razvan ME
> >>
> >>
> >> 2009/3/2 Janos Sallai <[email protected]>
> >>>
> >>> How about memcmp in string.h? This is standard C.
> >>>>
> >>>> Janos
> >>>>
> >>>> On Mon, Mar 2, 2009 at 11:13 AM, Jordi Pérez <[email protected]> wrote:
> >>>>
> >>>>> Dear all,
> >>>>>
> >>>>> I have a Base Station which receives the same packet from three
> >>>>> different
> >>>>> motes. The packets must be the same, but maybe, one of them could have
> >>>>> some
> >>>>> errors. So, I want to make a task which compare bit to bit, or byte to
> >>>>> byte,
> >>>>> the three packet received to rebuild a new packet without errors.
> >>>>>
> >>>>> How could I do this task? I don't know how to compare bit to bit (or
> >>>>> byte to
> >>>>> byte) a received packet. Can you help me please?
> >>>>>
> >>>>> Thanks in advanced,
> >>>>>
> >>>>> Jordi
> >>>>>
> >>>>>
> >>>>>
> >>>>
> >>>>
> >
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