Solveur pour la micro-enigma du premier magazine Next-INpact

nxigma.c

#include <stdio.h>
#include <string.h>

#define modulo 26
#define retour 0
#define aller 1

typedef int nxigma_rotor[2][modulo];
typedef int nxigma_reflector[modulo];

int ord(char c)
{
	return c - 'a';
}
char chr(int i)
{
	return 'a' + i;
}

int mod(int i)
{
	int ret = i % modulo;
	if (ret < 0)
	{
		return ret + modulo;
	}
	else
	{
		return ret;
	}
}

int apply_rotor(nxigma_rotor rotor, int input, int direction)
{
	return rotor[direction][input];
}

void init_rotor(nxigma_rotor rotor, char reflect2io[], char calibration)
{
	int rshift = ord(calibration);
	//printf("rshift = %d\n", rshift);
	for (int i = 0; i < 26; ++i)
	{
		int trad = ord(reflect2io[i]);
		rotor[retour][mod(i - rshift)] = mod(trad - rshift);
	}
	for (int i = 0; i < 26; ++i)
	{
		rotor[aller][rotor[retour][i]] = i;
	}
}

int init_reflector(nxigma_reflector reflector, char reflection[])
{
	for(int i = 0; i < modulo; ++i)
	{
		int rebond = ord(reflection[i]);
		reflector[i] = rebond;
	}
	for(int i = 0; i < modulo; ++i)
	{
		if (reflector[reflector[i]] != i)
		{
			return i;
		}
	}
	return -1;
}

int main(void)
{
	nxigma_rotor rotorN, rotorX, rotorI;
	nxigma_reflector reflectorNXI;
	init_rotor(rotorN, "uwygadfpvzbeckmthxslrinqoj", 'n');
	init_rotor(rotorX, "ajpczwrlfbdkotyuqgenhxmivs", 'x');
	init_rotor(rotorI, "tagbpcsdqeufvnzhyixjwlrkom", 'i');
	int i = init_reflector(reflectorNXI, "yruhqsldpxngokmiebfzcwvjat");
	if (i >= 0)
	{
		fprintf(stderr, "'%c' => '%c'\n", chr(i), chr(reflectorNXI[i]));
		fprintf(stderr, "'%c' => '%c'\n", chr(reflectorNXI[i]), chr(reflectorNXI[reflectorNXI[i]]));
	}
	char input[] = "avbkfrlkttcuc\0";
	for(i = 0; i < strlen(input); ++i)
	{
		int cur = ord(input[i]);
		cur = apply_rotor(rotorI, cur, aller);
		cur = apply_rotor(rotorX, cur, aller);
		cur = apply_rotor(rotorN, cur, aller);
		cur = reflectorNXI[cur];
		cur = apply_rotor(rotorN, cur, retour);
		cur = apply_rotor(rotorX, cur, retour);
		cur = apply_rotor(rotorI, cur, retour);
		printf("%c", chr(cur));
	}
	printf("\n");
}