hexdump.c

void hexdump(unsigned char *data, size_t size) {
	char ascii[17] = {0};
	size_t i;

	for (i = 0; i < size; ++i) {
		unsigned char c = data[i];
		size_t next = i+1;
		printf("%02X ", c);
		ascii[i % 16] = isprint(c) ? c : '.';
		if (next % 8 == 0 || next == size) {
			printf(" ");
			if (next % 16 == 0) {
				printf("|  %s \n", ascii);
			} 
			else if (next == size) {
				size_t j;
				ascii[size % 16] = '\0';
				if (size % 16 <= 8) {
					printf(" ");
				}
				for (j = size % 16; j < 16; ++j) {
					printf("   "); 
				}
				printf("|  %s \n", ascii);
			}
		}
		fflush(stdout);
	}
}