....
finalize(char *hdrs, sendip_data *headers[], int index,
sendip_data *data, sendip_data *pack)
{
........
For debugging purposes I want a hex dump of the data
and pack
structures, which are of type sendip_data
, a really complex structure. Actually they contain some binary information so I am not sure whether output of my project is correct or not. So for debugging purposes, I want to write the data into a file so that I can use hexdump as follows -
$hexdump -C file.txt
Also as this is a run time generation of a n/w packet so I am also not sure about the length of data
and pack
structure which I think fread / fwrite
will require ..So please suggest me something.
The following code will give you a hex dump of arbitrary memory from within your code.
#include <stdio.h>
void hexDump (const char * desc, const void * addr, const int len) {
int i;
unsigned char buff[17];
const unsigned char * pc = (const unsigned char *)addr;
// Output description if given.
if (desc != NULL)
printf ("%s:\n", desc);
// Length checks.
if (len == 0) {
printf(" ZERO LENGTH\n");
return;
}
else if (len < 0) {
printf(" NEGATIVE LENGTH: %d\n", len);
return;
}
// Process every byte in the data.
for (i = 0; i < len; i++) {
// Multiple of 16 means new line (with line offset).
if ((i % 16) == 0) {
// Don't print ASCII buffer for the "zeroth" line.
if (i != 0)
printf (" %s\n", buff);
// Output the offset.
printf (" %04x ", i);
}
// Now the hex code for the specific character.
printf (" %02x", pc[i]);
// And buffer a printable ASCII character for later.
if ((pc[i] < 0x20) || (pc[i] > 0x7e)) // isprint() may be better.
buff[i % 16] = '.';
else
buff[i % 16] = pc[i];
buff[(i % 16) + 1] = '\0';
}
// Pad out last line if not exactly 16 characters.
while ((i % 16) != 0) {
printf (" ");
i++;
}
// And print the final ASCII buffer.
printf (" %s\n", buff);
}
// Very simple test harness.
int main (int argc, char *argv[]) {
char my_str[] = "a char string greater than 16 chars";
hexDump ("my_str", &my_str, sizeof (my_str));
return 0;
}
You pass into hexDump
a description, memory address and length, and it will output a hex dump (including character data) for examination. When you run it with the included main
, the output is:
my_str:
0000 61 20 63 68 61 72 20 73 74 72 69 6e 67 20 67 72 a char string gr
0010 65 61 74 65 72 20 74 68 61 6e 20 31 36 20 63 68 eater than 16 ch
0020 61 72 73 00 ars.