[List.External:Keyboard]
int maxlength, length;	// Maximum passwords length to try, current length
int fuzz;		// The desired "fuzz factor", either 0 or 1
int id[15];		// Current character indices for each position
int m[0x400], mc[0x80];	// The keys matrix, counts of adjacent keys
int f[0x40], fc;	// Characters for the first position, their count

void init()
{
	int minlength;
	int i, j, c, p;
	int k[0x40];

	minlength = 7;	// Initial passwords length to try
	maxlength = 9;	// Maximum passwords length to try, up to 15
	fuzz = 1;	// "Fuzz factor", set to 0 for much quicker runs

/*
 * This defines the keyboard layout, by default for a QWERTY keyboard.
 * Please note that the sizes of m[] and mc[] arrays assume 7-bit
 * characters and will need to be doubled for 8-bit characters such as
 * umlauts.
 */
	i = 0; while (i < 0x40) k[i++] = 0;
	k[0] = '`';
	i = 0; while (++i <= 9) k[i] = '0' + i;
	k[10] = '0'; k[11] = '-'; k[12] = '=';
	k[0x11] = 'q'; k[0x12] = 'w'; k[0x13] = 'e'; k[0x14] = 'r';
	k[0x15] = 't'; k[0x16] = 'y'; k[0x17] = 'u'; k[0x18] = 'i';
	k[0x19] = 'o'; k[0x1a] = 'p'; k[0x1b] = '['; k[0x1c] = ']';
	k[0x1d] = '\\';
	k[0x21] = 'a'; k[0x22] = 's'; k[0x23] = 'd'; k[0x24] = 'f';
	k[0x25] = 'g'; k[0x26] = 'h'; k[0x27] = 'j'; k[0x28] = 'k';
	k[0x29] = 'l'; k[0x2a] = ';'; k[0x2b] = '\'';
	k[0x31] = 'z'; k[0x32] = 'x'; k[0x33] = 'c'; k[0x34] = 'v';
	k[0x35] = 'b'; k[0x36] = 'n'; k[0x37] = 'm'; k[0x38] = ',';
	k[0x39] = '.'; k[0x3a] = '/';

	i = 0; while (i < 0x80) mc[i++] = 0;
	fc = 0;

	/* rows */
	c = 0;
	i = 0;
	while (i < 0x40) {
		p = c;
		c = k[i++];
		if (!c) continue;
		f[fc++] = c;
		if (!p) continue;
		m[(c << 3) + mc[c]++] = p;
		m[(p << 3) + mc[p]++] = c;
	}
	f[fc] = 0;

	/* columns */
	i = 0;
	while (i < 0x30) {
		p = k[i++];
		if (!p) continue;
		j = 1 - fuzz;
		while (j <= 1 + fuzz) {
			c = k[i + 0x10 - j++];
			if (!c) continue;
			m[(c << 3) + mc[c]++] = p;
			m[(p << 3) + mc[p]++] = c;
		}
	}

	id[0] = 0;
	length = minlength;
}

void generate()
{
	int i, p, maxcount;

	word[i = 0] = p = f[id[0]];
	while (++i < length)
		word[i] = p = m[(p << 3) + id[i]];
	word[i--] = 0;

	if (i) maxcount = mc[word[i - 1]]; else maxcount = fc;
	while (++id[i] >= maxcount) {
		if (!i) {
			if (length < maxlength) {
				id[0] = 0;
				id[length++] = 0;
			}
			return;
		}
		id[i--] = 0;
		if (i) maxcount = mc[word[i - 1]]; else maxcount = fc;
	}
}

void restore()
{
	int i;

	/* Calculate the length */
	length = 0;
	while (word[length]) length++;

	/* Infer the first character index */
	i = -1;
	while (++i < fc) {
		if (f[i] == word[0]) {
			id[0] = i;
			break;
		}
	}

	/* This sample can be enhanced to infer the rest of the indices here */
}