From 10055958b65fe9c1be8a86b9b3d2957fc207eb79 Mon Sep 17 00:00:00 2001
From: Petr Baudis <pasky@ucw.cz>
Date: Sat, 28 May 2011 21:37:48 +0200
Subject: [PATCH] selfatari_cousin(): Make info on by-group available

---
 playout/moggy.c     | 4 ++--
 tactics/2lib.c      | 2 +-
 tactics/selfatari.c | 4 +++-
 tactics/selfatari.h | 5 +++--
 4 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/playout/moggy.c b/playout/moggy.c
index 5bb13ae..797b855 100644
--- a/playout/moggy.c
+++ b/playout/moggy.c
@@ -791,7 +791,7 @@ playout_moggy_assess_one(struct playout_policy *p, struct prior_map *map, coord_
 				return;
 			/* If we can play on the other liberty of the
 			 * endangered group, do! */
-			coord = selfatari_cousin(b, map->to_play, coord);
+			coord = selfatari_cousin(b, map->to_play, coord, NULL);
 			if (is_pass(coord))
 				return;
 			if (PLDEBUGL(5))
@@ -854,7 +854,7 @@ playout_moggy_permit(struct playout_policy *p, struct board *b, struct move *m)
 				stone2str(m->color), coord2sstr(m->coord, b));
 		if (pp->selfatari_other) {
 			/* Ok, try the other liberty of the atari'd group. */
-			coord_t c = selfatari_cousin(b, m->color, m->coord);
+			coord_t c = selfatari_cousin(b, m->color, m->coord, NULL);
 			if (is_pass(c)) return false;
 			if (PLDEBUGL(5))
 				fprintf(stderr, "___ Redirecting to other lib %s\n",
diff --git a/tactics/2lib.c b/tactics/2lib.c
index ab39cc6..d2e941e 100644
--- a/tactics/2lib.c
+++ b/tactics/2lib.c
@@ -143,7 +143,7 @@ can_atari_group(struct board *b, group_t group, enum stone owner,
 				/* Okay! We are attacker; maybe we just need
 				 * to connect a false eye before atari - this
 				 * is very common in the corner. */
-				coord = selfatari_cousin(b, to_play, lib);
+				coord = selfatari_cousin(b, to_play, lib, NULL);
 			}
 			if (is_pass(coord))
 				continue;
diff --git a/tactics/selfatari.c b/tactics/selfatari.c
index 816a918..c70efa6 100644
--- a/tactics/selfatari.c
+++ b/tactics/selfatari.c
@@ -511,7 +511,7 @@ is_bad_selfatari_slow(struct board *b, enum stone color, coord_t to)
 
 
 coord_t
-selfatari_cousin(struct board *b, enum stone color, coord_t coord)
+selfatari_cousin(struct board *b, enum stone color, coord_t coord, group_t *bygroup)
 {
 	group_t groups[4]; int groups_n = 0;
 	foreach_neighbor(b, coord, {
@@ -529,5 +529,7 @@ selfatari_cousin(struct board *b, enum stone color, coord_t coord)
 	coord_t lib2 = board_group_other_lib(b, group, coord);
 	if (is_bad_selfatari(b, color, lib2))
 		return pass;
+	if (bygroup)
+		*bygroup = group;
 	return lib2;
 }
diff --git a/tactics/selfatari.h b/tactics/selfatari.h
index 2e3c812..087cfd6 100644
--- a/tactics/selfatari.h
+++ b/tactics/selfatari.h
@@ -15,10 +15,11 @@ static bool is_bad_selfatari(struct board *b, enum stone color, coord_t to);
 
 /* Move (color, coord) is a selfatari; this means that it puts a group of
  * ours in atari; i.e., the group has two liberties now. Return the other
- * liberty of such a troublesome group if that one is not a self-atari.
+ * liberty of such a troublesome group (optionally stored at *bygroup)
+ * if that one is not a self-atari.
  * (In case (color, coord) is a multi-selfatari, consider a randomly chosen
  * candidate.) */
-coord_t selfatari_cousin(struct board *b, enum stone color, coord_t coord);
+coord_t selfatari_cousin(struct board *b, enum stone color, coord_t coord, group_t *bygroup);
 
 
 bool is_bad_selfatari_slow(struct board *b, enum stone color, coord_t to);
-- 
2.11.4.GIT