satdoompwd/satdoom_encode.c

/* saturn doom password gen */

#include <stdio.h>

#define MAX_BULLETS	400
#define MAX_SHELLS	100
#define MAX_ROCKETS	100
#define MAX_CELLS	600

#define MAX_HEALTH 200
#define MAX_ARMOR 200

/* where we'll store out generated password */
char password[10];

/* our look-up-table for password characters */
const char* pwlut = "BCDFGHJKLMNPQRSTVWXYZ0123456789!";

int
encode_value(int value, int maxvalue)
{
	int bit;

	if (value < 0)
		value = 0;
	if (value > maxvalue)
		value = maxvalue;

	/* we shift our value by 3 bits... this is odd */
	value = value << 3;
	bit = value / maxvalue;

	/* shift by one if we cannot cleanly divide */
	if (value % maxvalue != 0)
		bit += 1;

	return bit;
}

int
main(int args, char *argc)
{
	int i, bit;
	int nextmap;
	int gameskill;
	int itemquery;
  
	/* clear */
	for (i = 0; i < 10; i++)
		password[i] = 0;

	printf("Level? (1-59):\n");
	scanf("%d", &nextmap);
	if (nextmap < 1)
		nextmap = 1;
	if (nextmap > 59)
		nextmap = 59;

	printf("Skill? (0-3):\n");
	scanf("%d", &gameskill);
	if (gameskill < 0)
		gameskill = 0;
	if (gameskill > 3)
		gameskill = 3;

	/* we need to cache both values independently, because we split level
	 * and skill across 2 bytes */
	password[0] = (nextmap & 62) >> 1;
	password[1] = ((nextmap & 1) << 4) | ((gameskill & 3) << 2);

	printf("Item: Backpack? 0 = False, 1 = True:\n");
	scanf("%d", &itemquery);
	if (itemquery == 1)
		password[1] |= 2;

	/* weapons */
	printf("Item: Chainsaw? 0 = False, 1 = True:\n");
	scanf("%d", &itemquery);
	if (itemquery == 1)
		password[1] |=  1;

	printf("Item: BFG9000? 0 = False, 1 = True:\n");
	scanf("%d", &itemquery);
	if (itemquery == 1)
		password[2] |= 16;

	printf("Item: Plasma? 0 = False, 1 = True:\n");
	scanf("%d", &itemquery);
	if (itemquery == 1)
		password[2] |=  8;

	printf("Item: RPG? 0 = False, 1 = True:\n");
	scanf("%d", &itemquery);
	if (itemquery == 1)
		password[2] |=  4;

	printf("Item: Chaingun? 0 = False, 1 = True:\n");
	scanf("%d", &itemquery);
	if (itemquery == 1)
		password[2] |=  2;

	printf("Item: Double barrel shotgun? 0 = False, 1 = True:\n");
	scanf("%d", &itemquery);
	if (itemquery == 1)
		password[2] |=  1;

	printf("Item: Shotgun? 0 = False, 1 = True:\n");
	scanf("%d", &itemquery);
	if (itemquery == 1)
		password[3] |= 16;

	printf("Ammo: Clip? 0 = Min, 400 = Max:\n");
	scanf("%d", &itemquery);
	bit = encode_value(itemquery, MAX_BULLETS);
	password[3] |= (bit & 15);

	printf("Ammo: Shell? 0 = Min, 100 = Max:\n");
	scanf("%d", &itemquery);
	bit = encode_value(itemquery, MAX_SHELLS);
	password[4] |= (bit & 15) << 1;

	printf("Ammo: Cell? 0 = Min, 600 = Max:\n");
	scanf("%d", &itemquery);
	bit = encode_value(itemquery, MAX_CELLS);
	password[4] |= (bit & 8) >> 3;
	password[5] |= (bit & 7) << 2;

	printf("Ammo: Rockets? 0 = Min, 100 = Max:\n");
	scanf("%d", &itemquery);
	bit = encode_value(itemquery, MAX_ROCKETS);
	password[5] |= (bit & 12) >> 2;
	password[6] |= (bit &  3) << 3;

	printf("Health? 0 = Min, 200 = Max:\n");
	scanf("%d", &itemquery);
	bit = encode_value(itemquery, MAX_HEALTH);
	password[6] |= (bit & 14) >> 1;
	password[7] |= (bit &  1) << 4;

	printf("Armor? 0 = Min, 200 = Max:\n");
	scanf("%d", &itemquery);
	bit = encode_value(itemquery, MAX_ARMOR);
	password[7] |= (bit & 15);

	printf("Armor Type? 0 = None, 1 = Green, 2 = Blue:\n");
	scanf("%d", &itemquery);
	if (itemquery < 0)
		itemquery = 0;
	if (itemquery > 2)
		itemquery = 2;
	password[8] |= itemquery;
  
	/* generate our decryption value */
	for (i = 0; i < 9; i++)
		password[9] ^= password[i];

	/* encrypt our password using the calculated XOR value */
	for (i = 0; i < 9; i++)
		password[i] ^= password[9];

	/* print it out to screen */
	printf("Your password: ");
	for (i = 0; i < 10; i++)
		printf("%c", pwlut[password[i]]);

	printf("\n");

	return 1;
}