hexdump.cpp

#include <iostream>
#include <sstream>
#include <string>
#include <cstdint>
#include <cctype>

static int round_up_div(int val, int div){
	return (val + div - 1) / div;
}

#define HEXDUMP_ROW_PRESIZE 0x3D
#define HEXDUMP_ROW_POSTSIZE 0x11
#define HEXDUMP_ROW_SIZE 0x60
static void hexdump(std::ostream& out, void *pData, size_t length){
	uint8_t *bytes = (uint8_t *)pData;
	if(bytes == NULL || length == 0){
		return;
	}

	size_t max = round_up_div(length, HEXDUMP_ROW_SIZE) * HEXDUMP_ROW_SIZE;
	char buf[max];

	std::stringstream ss;
	ss.rdbuf()->pubsetbuf(buf, sizeof(buf));

	size_t i = 0, j = 0, octets = 0;
	while (i < length) {
		// print address every 16 bytes
		int offset = i & 15;
		if (offset == 0) {
			ss << ssprintf("%08X    ", i);
		}

		// print byte
		ss << ssprintf("%02X ", bytes[i++]);

		// octets spacing
		if (i > 0 && (i & 7) == 0) {
			if (octets++ < 1){
				ss << ' ';
			}
		}

		if (octets == 2 || i == length) {
			// fill blanks
			off_t row_offs = ss.tellp() % HEXDUMP_ROW_SIZE;
			if(row_offs > 0){
				size_t needed = HEXDUMP_ROW_SIZE - HEXDUMP_ROW_POSTSIZE - row_offs;
				ss << std::string(needed, ' ');
			}

			// go back to saved pos, and print the bytes content
			for (size_t k = j; k < i; k++) {
				if (!isprint((char)bytes[k])){
					ss << '.';
				} else {
					ss << (char)(bytes[k]);
				}
			}
			ss << '\n';

			j = i;
			octets = 0;
		}
	}
	out << ss.str();
}