[src/trunk]: src/games/gomoku gomoku: fix error handling when reading moves f...

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

details:   https://anonhg.NetBSD.org/src/rev/6c0c977baec3
branches:  trunk
changeset: 366284:6c0c977baec3
user:      rillig <rillig%NetBSD.org@localhost>
date:      Sat May 21 19:02:14 2022 +0000

description:
gomoku: fix error handling when reading moves from a file

The columns of the board are labeled from A to H and J to T, which makes
I5 or i5 an invalid coordinate.  Previously, reading this invalid
coordinate from a file resulted in the string "<6" appearing in the move
log.

The 'i' was converted into the nonexistent column 20, and PT(20, 5) got
an out-of-bounds argument, resulting in spot 120.  Converting this spot
back into coordinates resulted in PT(0, 6).  The '<' comes from
'letters[0]'.

diffstat:

 games/gomoku/main.c |  10 ++++----
 games/gomoku/stoc.c |  61 ++++++++++++++++++----------------------------------
 2 files changed, 26 insertions(+), 45 deletions(-)

diffs (141 lines):

diff -r d778c9bff905 -r 6c0c977baec3 games/gomoku/main.c
--- a/games/gomoku/main.c       Sat May 21 17:50:21 2022 +0000
+++ b/games/gomoku/main.c       Sat May 21 19:02:14 2022 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: main.c,v 1.48 2022/05/21 17:19:10 rillig Exp $ */
+/*     $NetBSD: main.c,v 1.49 2022/05/21 19:02:14 rillig Exp $ */
 
 /*
  * Copyright (c) 1994
@@ -36,7 +36,7 @@
 __COPYRIGHT("@(#) Copyright (c) 1994\
  The Regents of the University of California.  All rights reserved.");
 /*     @(#)main.c      8.4 (Berkeley) 5/4/95   */
-__RCSID("$NetBSD: main.c,v 1.48 2022/05/21 17:19:10 rillig Exp $");
+__RCSID("$NetBSD: main.c,v 1.49 2022/05/21 19:02:14 rillig Exp $");
 
 #include <sys/stat.h>
 #include <curses.h>
@@ -235,7 +235,7 @@
                switch (input[color]) {
                case INPUTF: /* input comes from a file */
                        curmove = readinput(inputfp);
-                       if (curmove != ILLEGAL)
+                       if (curmove != EOF)
                                break;
                        /* Switch to another input source. */
                        switch (test) {
@@ -305,7 +305,7 @@
                        curmove = pickmove(color);
                        break;
                }
-               if (interactive) {
+               if (interactive && curmove != ILLEGAL) {
                        misclog("%3d%*s%-6s", movenum,
                            color == BLACK ? 2 : 9, "", stoc(curmove));
                }
@@ -372,7 +372,7 @@
        while ((c = getc(fp)) != EOF && c != '\n' && pos < sizeof(buf) - 1)
                buf[pos++] = c;
        buf[pos] = '\0';
-       return ctos(buf);
+       return c == EOF ? EOF : ctos(buf);
 }
 
 #ifdef DEBUG
diff -r d778c9bff905 -r 6c0c977baec3 games/gomoku/stoc.c
--- a/games/gomoku/stoc.c       Sat May 21 17:50:21 2022 +0000
+++ b/games/gomoku/stoc.c       Sat May 21 19:02:14 2022 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: stoc.c,v 1.19 2022/05/21 17:19:10 rillig Exp $ */
+/*     $NetBSD: stoc.c,v 1.20 2022/05/21 19:02:14 rillig Exp $ */
 
 /*
  * Copyright (c) 1994
@@ -34,7 +34,7 @@
 
 #include <sys/cdefs.h>
 /*     @(#)stoc.c      8.1 (Berkeley) 7/24/94  */
-__RCSID("$NetBSD: stoc.c,v 1.19 2022/05/21 17:19:10 rillig Exp $");
+__RCSID("$NetBSD: stoc.c,v 1.20 2022/05/21 19:02:14 rillig Exp $");
 
 #include <ctype.h>
 #include <stdlib.h>
@@ -43,19 +43,6 @@
 
 const char     letters[]       = "<ABCDEFGHJKLMNOPQRST>";
 
-struct mvstr {
-       int     m_code;
-       const char      *m_text;
-};
-static const struct    mvstr   mv[] = {
-       { RESIGN,       "resign" },
-       { RESIGN,       "quit" },
-       { SAVE,         "save" },
-       { -1,           0 }
-};
-
-static int lton(int);
-
 
 /*
  * Turn the spot number form of a move into the character form.
@@ -65,9 +52,10 @@
 {
        static char buf[32];
 
-       for (int i = 0; mv[i].m_code >= 0; i++)
-               if (s == mv[i].m_code)
-                       return mv[i].m_text;
+       if (s == RESIGN)
+               return "resign";
+       if (s == SAVE)
+               return "save";
        snprintf(buf, sizeof(buf), "%c%d",
            letters[s % (BSZ + 1)], s / (BSZ + 1));
        return buf;
@@ -80,28 +68,21 @@
 ctos(const char *mp)
 {
 
-       for (int i = 0; mv[i].m_code >= 0; i++)
-               if (strcmp(mp, mv[i].m_text) == 0)
-                       return mv[i].m_code;
-       if (!isalpha((unsigned char)mp[0]))
-               return ILLEGAL;
-       int i = atoi(&mp[1]);
-       if (i < 1 || i > 19)
-               return ILLEGAL;
-       return PT(lton((unsigned char)mp[0]), i);
-}
+       if (strcmp(mp, "resign") == 0 || strcmp(mp, "quit") == 0)
+               return RESIGN;
+       if (strcmp(mp, "save") == 0)
+               return SAVE;
 
-/*
- * Turn a letter into a number.
- */
-static int
-lton(int c)
-{
-       int i;
+       int letter = toupper((unsigned char)mp[0]);
+       int x = 1;
+       while (x <= BSZ && letters[x] != letter)
+               x++;
+       if (x > BSZ)
+               return ILLEGAL;
 
-       if (islower(c))
-               c = toupper(c);
-       for (i = 1; i <= BSZ && letters[i] != c; i++)
-               ;
-       return i;
+       int y = atoi(&mp[1]);
+       if (y < 1 || y > 19)
+               return ILLEGAL;
+
+       return PT(x, y);
 }