Compact C Hex Dump Function w/ASCII

DumpHex.c

#include <stdio.h>

void DumpHex(const void* data, size_t size) {
	char ascii[17];
	size_t i, j;
	ascii[16] = '\0';
	for (i = 0; i < size; ++i) {
		printf("%02X ", ((unsigned char*)data)[i]);
		if (((unsigned char*)data)[i] >= ' ' && ((unsigned char*)data)[i] <= '~') {
			ascii[i % 16] = ((unsigned char*)data)[i];
		} else {
			ascii[i % 16] = '.';
		}
		if ((i+1) % 8 == 0 || i+1 == size) {
			printf(" ");
			if ((i+1) % 16 == 0) {
				printf("|  %s \n", ascii);
			} else if (i+1 == size) {
				ascii[(i+1) % 16] = '\0';
				if ((i+1) % 16 <= 8) {
					printf(" ");
				}
				for (j = (i+1) % 16; j < 16; ++j) {
					printf("   ");
				}
				printf("|  %s \n", ascii);
			}
		}
	}
}

Oh, thanks )

Hi All, Thanks ccbrown. Very good work.
If you are interested in enabling column specification to this code try these modifications:

1. Add #include <stdlib.h>
2. Change Line 3: void DumpHex(const void* data, size_t size, size_t columns) {
3. Replace line 4: with :
   size_t half_columns = (columns/2);
   columns = half_columns * 2;
   char *ascii = (char *) malloc(columns+1);
4. Change both occurrences of "8" with 'half_columns' and the 8 occurrences of "16" with 'columns'
5. Finally insert this after line 29:
   free(ascii);

Enjoy.

Thank you 👍👍👍

i copied this snippet so many times, it's actually amazing- thank you! really useful when debugging random byte crap :>

Thank you for sharing this!! 👍

I used this code for debugging in my personal project here and blog post that explains it.

Thank you for this useful function.
I revised it and removed usage of printf function. Instead, a string buffer (strBuffer) is used for each line.
Also, DumpHex has third parameter - a pointer to a function that outputs the lines to the output (or to a file, or to a serial port or where the user wants to).

Renamed function to dump_hex.

Here is the link.

You don't know the number of times I came back here and copied this code, much appreciated! 🙏🙏🙏