Question

kay so this

void printPacketBuffer(void *buffer, unsigned int length)
{
    unsigned int i=0;
    char *c;
    unsigned int limit = ( (length != 0)?length:PACKET_DATA );
    for (i=0; i<limit; i++) {
        c = (char *)(buffer+i);
        if ( *c != '\0' ) {
            printf("%c", *c);
        }
    }
}

is working but the following function short miss the last 14 bytes can’t understand why ?!

void printPacket (void * buffer) {
    unsigned int size = getPacket_size(buffer);
    printf("\n***********\nNew Packet holding %d bytes of data\n***********\n", size);
    char *c;
    int counter=0;
    int i;
    for (i=2; i<size+2; i++) {
        c = (char *)(buffer+i);
        if ( *c != '\0' ) {
            printf("%c", *c);
            counter++;
        }
    }
    printf("\nactual printing %d, i=%d\n", counter, i);
}

and here is the calls

printPacketBuffer(pbuffer+2, getPacket_size(pbuffer));
printPacket(pbuffer);

Answer 1

i supposed that pbuffer+2 is the next address by two bytes but I was WRONG here’s what was happening
if bpuffer = 0x7fff2c03d8a0 the bpuffer + 2 = 0x7fff2c03d8b0
now to move to next 2 bytes location I used

void *temp = (char *)pbuffer+shift;

anyway the morale of the story is to work with bytes cast to unsigned char

void printPacket (void * buffer) {
    unsigned int size = getPacket_size(buffer);
    printf("\n***********\nNew Packet holding %d bytes of data %p\n***********\n", size, buffer);
    char *c;
    int counter=0;
    int i;
    for (i=2; i<size+2; i++) {
        c = (char *)buffer+i;
        if ( *c != '\0' ) {
            printf("%c", *c);
            counter++;
        }
        else {
            printf("NULL ");
        }
    }
}