in source/huffman_generator/generator.c [108:114]
void code_write(struct huffman_code *code, FILE *file) {
for (int bit_idx = code->num_bits - 1; bit_idx >= 0; --bit_idx) {
char bit = ((code->bits >> bit_idx) & 0x1) ? '1' : '0';
fprintf(file, "%c", bit);
}
}