[src/trunk]: src/games/gomoku gomoku: extract separate function update_overla...

[rillig <rillig%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/64dd6228a8a9
branches:  trunk
changeset: 366460:64dd6228a8a9
user:      rillig <rillig%NetBSD.org@localhost>
date:      Sat May 28 05:44:41 2022 +0000

description:
gomoku: extract separate function update_overlap_same_direction

No functional change.

diffstat:

 games/gomoku/makemove.c |  97 ++++++++++++++++++++++++++----------------------
 1 files changed, 53 insertions(+), 44 deletions(-)

diffs (153 lines):

diff -r 90b8f577c173 -r 64dd6228a8a9 games/gomoku/makemove.c
--- a/games/gomoku/makemove.c   Sat May 28 05:14:34 2022 +0000
+++ b/games/gomoku/makemove.c   Sat May 28 05:44:41 2022 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: makemove.c,v 1.27 2022/05/28 05:14:34 rillig Exp $     */
+/*     $NetBSD: makemove.c,v 1.28 2022/05/28 05:44:41 rillig Exp $     */
 
 /*
  * Copyright (c) 1994
@@ -34,7 +34,7 @@
 
 #include <sys/cdefs.h>
 /*     @(#)makemove.c  8.2 (Berkeley) 5/3/95   */
-__RCSID("$NetBSD: makemove.c,v 1.27 2022/05/28 05:14:34 rillig Exp $");
+__RCSID("$NetBSD: makemove.c,v 1.28 2022/05/28 05:44:41 rillig Exp $");
 
 #include "gomoku.h"
 
@@ -77,10 +77,9 @@
 
        /* compute new frame values */
        sp->s_wval = 0;
-       struct spotstr *osp = sp;
        for (int r = 4; --r >= 0; ) {           /* for each direction */
            int d = dd[r];
-           struct spotstr *fsp = osp;
+           struct spotstr *fsp = &board[mv];
            int bmask = BFLAG << r;
 
            for (int f = 5; --f >= 0; fsp -= d) {       /* for each frame */
@@ -198,7 +197,7 @@
            ;
        }
 
-       update_overlap(osp);
+       update_overlap(&board[mv]);
 
        /*
         * TODO: Declare a tie as soon as all frames are blocked. This is
@@ -210,8 +209,52 @@
        return MOVEOK;
 }
 
+static void
+update_overlap_same_direction(const struct spotstr *sp1,
+                             const struct spotstr *sp2,
+                             int a, int d, int i_minus_f, int r)
+{
+       /*
+        * count the number of empty spots to see if there is
+        * still an overlap.
+        */
+       int n = 0;
+       const struct spotstr *sp = sp1;
+       const struct spotstr *esp = NULL;
+       for (int b = i_minus_f; b < 5; b++, sp += d) {
+               if (sp->s_occ == EMPTY) {
+                       esp = sp;       /* save the intersection point */
+                       n++;
+               }
+       }
+
+       int b = (int)(sp2->s_frame[r] - frames);
+       if (n == 0) {
+               if (sp->s_occ == EMPTY) {
+                       overlap[a * FAREA + b] &= 0xA;
+                       overlap[b * FAREA + a] &= 0xC;
+                       intersect[a * FAREA + b] = (short)(sp - board);
+                       intersect[b * FAREA + a] = (short)(sp - board);
+               } else {
+                       overlap[a * FAREA + b] = 0;
+                       overlap[b * FAREA + a] = 0;
+               }
+       } else if (n == 1) {
+               if (sp->s_occ == EMPTY) {
+                       overlap[a * FAREA + b] &= 0xAF;
+                       overlap[b * FAREA + a] &= 0xCF;
+               } else {
+                       overlap[a * FAREA + b] &= 0xF;
+                       overlap[b * FAREA + a] &= 0xF;
+               }
+               intersect[a * FAREA + b] = (short)(esp - board);
+               intersect[b * FAREA + a] = (short)(esp - board);
+       }
+       /* else no change, still multiple overlap */
+}
+
 /*
- * fix up the overlap array due to updating spot osp.
+ * fix up the overlap array according to the changed 'osp'.
  */
 static void
 update_overlap(struct spotstr *osp)
@@ -221,11 +264,13 @@
            int d = dd[r];
            struct spotstr *sp1 = osp;
 
-           for (int f = 0; f < 6; f++, sp1 -= d) {     /* for each frame */
+           /* for each frame that contains 'osp' */
+           for (int f = 0; f < 6; f++, sp1 -= d) {
                if (sp1->s_occ == BORDER)
                    break;
                if ((sp1->s_flags & BFLAG << r) != 0)
                    continue;
+
                /*
                 * Update all other frames that intersect the current one
                 * to indicate whether they still overlap or not.
@@ -242,43 +287,7 @@
                    if ((sp2->s_flags & BFLAG << r) != 0)
                        continue;
 
-                   /*
-                    * count the number of empty spots to see if there is
-                    * still an overlap.
-                    */
-                   int n = 0;
-                   struct spotstr *sp = sp1;
-                   struct spotstr *esp = NULL;
-                   for (int b = i - f; b < 5; b++, sp += d) {
-                       if (sp->s_occ == EMPTY) {
-                           esp = sp;   /* save the intersection point */
-                           n++;
-                       }
-                   }
-
-                   int b = (int)(sp2->s_frame[r] - frames);
-                   if (n == 0) {
-                       if (sp->s_occ == EMPTY) {
-                           overlap[a * FAREA + b] &= 0xA;
-                           overlap[b * FAREA + a] &= 0xC;
-                           intersect[a * FAREA + b] = (short)(sp - board);
-                           intersect[b * FAREA + a] = (short)(sp - board);
-                       } else {
-                           overlap[a * FAREA + b] = 0;
-                           overlap[b * FAREA + a] = 0;
-                       }
-                   } else if (n == 1) {
-                       if (sp->s_occ == EMPTY) {
-                           overlap[a * FAREA + b] &= 0xAF;
-                           overlap[b * FAREA + a] &= 0xCF;
-                       } else {
-                           overlap[a * FAREA + b] &= 0xF;
-                           overlap[b * FAREA + a] &= 0xF;
-                       }
-                       intersect[a * FAREA + b] = (short)(esp - board);
-                       intersect[b * FAREA + a] = (short)(esp - board);
-                   }
-                   /* else no change, still multiple overlap */
+                   update_overlap_same_direction(sp1, sp2, a, d, i - f, r);
                }
 
                /* the other directions can only intersect at spot osp */