From 6a8e91836755ce865bb6a8fdfbcc8afa2c01512a Mon Sep 17 00:00:00 2001
From: Petr Baudis <pasky@ucw.cz>
Date: Mon, 22 Sep 2008 02:50:02 +0200
Subject: [PATCH] Symmetry: Remove symmetry.free and symmetry.d<0 bogosity

---
 board.c    | 58 +++++++++++-----------------------------------------------
 board.h    |  5 +----
 uct/tree.c |  4 ++--
 3 files changed, 14 insertions(+), 53 deletions(-)

diff --git a/board.c b/board.c
index 42c6bb0..d2493c5 100644
--- a/board.c
+++ b/board.c
@@ -134,11 +134,10 @@ board_clear(struct board *board)
 	board_resize(board, size - 2 /* S_OFFBOARD margin */);
 
 	/* Setup initial symmetry */
-	board->symmetry.d = -1;
+	board->symmetry.d = 1;
 	board->symmetry.x1 = board->symmetry.y1 = board->size / 2;
 	board->symmetry.x2 = board->symmetry.y2 = board->size - 1;
 	board->symmetry.type = SYM_FULL;
-	board->symmetry.free = true;
 
 	/* Draw the offboard margin */
 	int top_row = board_size2(board) - board_size(board);
@@ -270,9 +269,9 @@ board_symmetry_update(struct board *b, struct board_symmetry *symmetry, coord_t
 	int x = coord_x(c, b), y = coord_y(c, b), t = board_size(b) / 2;
 	int dx = board_size(b) - 1 - x; /* for SYM_DOWN */
 	if (DEBUGL(6)) {
-		fprintf(stderr, "SYMMETRY [%d,%d,%d,%d|%d=%d+%d] update for %d,%d\n",
+		fprintf(stderr, "SYMMETRY [%d,%d,%d,%d|%d=%d] update for %d,%d\n",
 			symmetry->x1, symmetry->y1, symmetry->x2, symmetry->y2,
-			symmetry->d, symmetry->type, symmetry->free, x, y);
+			symmetry->d, symmetry->type, x, y);
 	}
 
 	switch (symmetry->type) {
@@ -313,63 +312,28 @@ break_symmetry:
 		case SYM_DIAG_UP:
 			if (x == y)
 				return;
-			if (symmetry->d > 0 ? x < y : x > y) {
-				/* Good side of symmetry. Just froze it. */
-				symmetry->free = false;
-			} else if (symmetry->free) {
-				/* Flip symmetry. */
-				symmetry->d = - symmetry->d;
-				symmetry->free = false;
-			} else {
-				/* Break symmetry. */
-				goto break_symmetry;
-			}
-			break;
+			goto break_symmetry;
 		case SYM_DIAG_DOWN:
 			if (dx == y)
 				return;
-			if (symmetry->d > 0 ? dx < y : dx > y) {
-				symmetry->free = false;
-			} else if (symmetry->free) {
-				symmetry->d = - symmetry->d;
-				symmetry->free = false;
-			} else {
-				goto break_symmetry;
-			}
-			break;
+			goto break_symmetry;
 		case SYM_HORIZ:
 			if (x == t)
 				return;
-			if (symmetry->x1 <= x && x <= symmetry->x2) {
-				symmetry->free = false;
-			} else if (symmetry->free) {
-				symmetry->x1 = t;
-				symmetry->x2 = board_size(b) - 1;
-				symmetry->free = false;
-			} else {
-				goto break_symmetry;
-			}
-			break;
+			goto break_symmetry;
 		case SYM_VERT:
-			if (symmetry->y1 <= y && y <= symmetry->y2) {
-				symmetry->free = false;
-			} else if (symmetry->free) {
-				symmetry->y1 = t;
-				symmetry->y2 = board_size(b) - 1;
-				symmetry->free = false;
-			} else {
-				goto break_symmetry;
-			}
-			break;
+			if (y == t)
+				return;
+			goto break_symmetry;
 		case SYM_NONE:
 			assert(0);
 			break;
 	}
 
 	if (DEBUGL(6)) {
-		fprintf(stderr, "NEW SYMMETRY [%d,%d,%d,%d|%d=%d+%d]\n",
+		fprintf(stderr, "NEW SYMMETRY [%d,%d,%d,%d|%d=%d]\n",
 			symmetry->x1, symmetry->y1, symmetry->x2, symmetry->y2,
-			symmetry->d, symmetry->type, symmetry->free);
+			symmetry->d, symmetry->type);
 	}
 	/* Whew. */
 }
diff --git a/board.h b/board.h
index 56c953c..b86ed58 100644
--- a/board.h
+++ b/board.h
@@ -28,8 +28,7 @@ struct board_symmetry {
 	/* Playground is in this rectangle. */
 	int x1, x2, y1, y2;
 	/* d ==  0: Full rectangle
-	 * d == -1: x <= y rectangle
-	 * d ==  1: x >= y rectangle */
+	 * d ==  1: Top triangle */
 	int d;
 	/* General symmetry type. */
 	enum {
@@ -40,8 +39,6 @@ struct board_symmetry {
 		SYM_VERT,
 		SYM_NONE
 	} type;
-	/* Can we flip symmetry if necessary? */
-	bool free;
 };
 
 
diff --git a/uct/tree.c b/uct/tree.c
index 024667e..d09b9a8 100644
--- a/uct/tree.c
+++ b/uct/tree.c
@@ -197,7 +197,7 @@ tree_expand_node(struct tree *t, struct tree_node *node, struct board *b, enum s
 		for (int j = b->symmetry.y1; j <= b->symmetry.y2; j++) {
 			if (b->symmetry.d) {
 				int x = b->symmetry.type == SYM_DIAG_DOWN ? board_size(b) - 1 - i : i;
-				if (b->symmetry.d < 0 ? x < j : x > j) {
+				if (x > j) {
 					if (UDEBUGL(7))
 						fprintf(stderr, "drop %d,%d\n", i, j);
 					continue;
@@ -262,7 +262,7 @@ tree_fix_symmetry(struct tree *tree, struct board *b, coord_t c)
 	if (s->d) {
 		bool dir = (s->type == SYM_DIAG_DOWN) ^ flip_horiz ^ flip_vert;
 		int x = dir ? board_size(b) - 1 - cx : cx;
-		if (s->d < 0 ? x < cy : x > cy) {
+		if (x > cy) {
 			flip_diag = 1 + dir;
 		}
 	}
-- 
2.11.4.GIT