bindump.c

// print each byte from [begin, end) in groups of four per line
void bindump(const uint8_t* begin, const uint8_t* end) {
    printf("BIN[%p, %p)\n", begin, end);
    char bytestr[9];
    bytestr[8] = '\0';
    for (uint8_t j = 1; begin != end; begin++, j++) {
        uint8_t byte = *begin;
        for (int i = 0; i < 8; i++)
            bytestr[i] = '0' + ((byte >> (7-i)) & 1);
        printf("%s%c", bytestr, j & 3 ? ' ' : '\n');
    }
    putchar('\n');
}