# Generic implementation of exhaustive search for a partially-known password.
# init() may be modified to use arbitrary character sets for each position.
[List.External:KnownForce]
int last;		// Last character position, zero-based
int lastofs;		// Last character position offset into charset[]
int lastid;		// Current character index in the last position
int id[0x7f];		// Current character indices for other positions
int charset[0x7f00];	// Character sets, 0x100 elements for each position

void init()
{
	int length;
	int pos, ofs, i, c;

	length = 8;	// Password length to try

/* This defines the character sets for different character positions */
	pos = 0;
/* Position 1 */
	ofs = pos++ << 8;
	i = 0;
	c = 'a';
	while (c <= 'z')
		charset[ofs + i++] = c++;
	c = 'A';
	while (c <= 'Z')
		charset[ofs + i++] = c++;
	charset[ofs + i] = 0;
/* Positions 2, 3, 4 */
	while (pos < 4) {
		ofs = pos++ << 8;
		i = 0;
		c = '0';
		while (c <= '9')
			charset[ofs + i++] = c++;
		charset[ofs + i] = 0;
	}
/* Position 5 */
	ofs = pos++ << 8;
	i = 0;
	c = 'a';
	while (c <= 'z')
		charset[ofs + i++] = c++;
	c = 'A';
	while (c <= 'Z')
		charset[ofs + i++] = c++;
	charset[ofs + i] = 0;
/* Positions 6, 7, 8 */
	while (pos < length) {
		ofs = pos++ << 8;
		i = 0;
		c = '0';
		while (c <= '9')
			charset[ofs + i++] = c++;
		charset[ofs + i] = 0;
	}

	last = length - 1;
	pos = -1;
	while (++pos <= last)
		word[pos] = charset[id[pos] = pos << 8];
	lastid = (lastofs = last << 8) - 1;
	word[pos] = 0;
}

void generate()
{
	int pos;

/* Handle the typical case specially */
	if (word[last] = charset[++lastid]) return;

	word[pos = last] = charset[lastid = lastofs];
	while (pos--) {			// Have a preceding position?
		if (word[pos] = charset[++id[pos]]) return;
		word[pos] = charset[id[pos] = pos << 8];
	}

	word = 0;			// We're done
}

void restore()
{
	int i, c;

/* Calculate the current length and infer the character indices */
	last = 0;
	while (c = word[last]) {
		i = lastofs = last << 8;
		while (charset[i] != c && charset[i]) i++;
		if (!charset[i]) i = lastofs; // Not found
		id[last++] = i;
	}
	lastid = id[--last];
}