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/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *\
* This is GNU Go, a Go program. Contact gnugo@gnu.org, or see *
* http://www.gnu.org/software/gnugo/ for more information. *
* *
* Copyright 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, *
* 2008 and 2009 by the Free Software Foundation. *
* *
* This program is free software; you can redistribute it and/or *
* modify it under the terms of the GNU General Public License as *
* published by the Free Software Foundation - version 3 or *
* (at your option) any later version. *
* *
* This program is distributed in the hope that it will be useful, *
* but WITHOUT ANY WARRANTY; without even the implied warranty of *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
* GNU General Public License in file COPYING for more details. *
* *
* You should have received a copy of the GNU General Public *
* License along with this program; if not, write to the Free *
* Software Foundation, Inc., 51 Franklin Street, Fifth Floor, *
* Boston, MA 02111, USA. *
\* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
#include "liberty.h"
#include "dfa.h"
#include <memory.h>
/* Array for use by TRANSFORM() macro. */
int transformation[MAX_OFFSET][8];
/* Matrix array for use by TRANSFORM2() macro. */
const int transformation2[8][2][2] = {
{ { 1, 0},
{ 0, 1}}, /* a - identity transformation matrix */
{ { 0, 1},
{-1, 0}}, /* g - rotate 90 clockwise */
{ {-1, 0},
{ 0, -1}}, /* d - rotate 180 */
{ { 0, -1},
{ 1, 0}}, /* f - rotate 90 counter-clockwise */
{ { 0, -1},
{-1, 0}}, /* h - rotate 90 clockwise and flip on x axis */
{ {-1, 0},
{ 0, 1}}, /* b - flip on x axis */
{ { 0, 1},
{ 1, 0}}, /* e - rotate 90 counter-clockwise and flip on x axis */
{ { 1, 0},
{ 0, -1}} /* c - flip on y axis */
};
/* Initialize transformation[][] array. */
void
transformation_init(void)
{
int k;
int dx;
int dy;
for (k = 0; k < 8; k++) {
for (dy = -MAX_BOARD+1; dy <= MAX_BOARD-1; dy++) {
for (dx = -MAX_BOARD+1; dx <= MAX_BOARD-1; dx++) {
int tx;
int ty;
TRANSFORM2(dx, dy, &tx, &ty, k);
transformation[OFFSET(dx, dy)][k] = DELTA(tx, ty);
}
}
}
}
/* Spiral orders for DFA matching and building. */
int spiral[DFA_MAX_ORDER][8];
/* The spiral order is the way we scan the board, we begin on the
* anchor and we progressively scan all its neigbouring intersections,
* collecting all the known patterns we meet on our way:
*
* 4 4 4
* 1 1 13 13 513 513 ... and so on until we reach a
* 2 2 2 2 827 stopping state in the DFA.
* 6
*
* Build the spiral order for each transformation: instead of changing
* the board or changing the patterns, we only change the order. For
* e.g. the same DFA can perform the pattern matching
*
* That way for identity:
*
* 40 04
* 5139 and this way for mirror symetry: 9315
* 827 728
* 6 6
*
* Anther possibility is to generate one string by pattern and by
* transformation in `mkpat' to avoid any runtime transformation but
* it drastically increases the size of DFAs.
*/
void
build_spiral_order(void)
{
int i;
int j;
int k;
char mark[2 * DFA_MAX_BOARD + 1][2 * DFA_MAX_BOARD + 1];
int queue_i[DFA_MAX_ORDER];
int queue_j[DFA_MAX_ORDER];
int queue_start = 0;
int queue_end = 1;
static const int delta_i[4] = { 1, 0, -1, 0};
static const int delta_j[4] = { 0, 1, 0, -1};
/* Initialization. */
memset(mark, 1, sizeof(mark));
for (i = 1; i < 2 * DFA_MAX_BOARD; i++) {
for (j = 1; j < 2 * DFA_MAX_BOARD; j++)
mark[i][j] = 0;
}
queue_i[0] = DFA_MAX_BOARD;
queue_j[0] = DFA_MAX_BOARD;
mark[DFA_MAX_BOARD][DFA_MAX_BOARD] = 1;
do {
int transformation;
/* Transform queued coordinates and store DFA offsets in spiral[][]. */
for (transformation = 0; transformation < 8; transformation++) {
TRANSFORM2(queue_i[queue_start] - DFA_MAX_BOARD,
queue_j[queue_start] - DFA_MAX_BOARD,
&i, &j, transformation);
spiral[queue_start][transformation] = DFA_BASE * i + j;
}
for (k = 0; k < 4; k++) {
i = queue_i[queue_start] + delta_i[k];
j = queue_j[queue_start] + delta_j[k];
if (!mark[i][j]) {
queue_i[queue_end] = i;
queue_j[queue_end++] = j;
mark[i][j] = 1;
}
}
} while (++queue_start < queue_end);
if (0) {
int transformation;
for (transformation = 0; transformation < 8; transformation++) {
fprintf(stderr, "Transformation %d:\n", transformation);
for (k = 0; k < 16; k++) {
fprintf(stderr, "\t%d(%c); %d\n", k, 'A' + k,
spiral[k][transformation]);
}
}
}
}
/*
* Local Variables:
* tab-width: 8
* c-basic-offset: 2
* End:
*/
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