Standalone compilation mode which turns mines.c into a little

utility to convert descriptive game IDs containing mine bitmaps
between obfuscated and cleartext. Might be handy for anyone planning
to design custom levels to send to friends (mines spelling out
`Happy Birthday', that sort of thing), as someone suggested to me
today :-)

[originally from svn r5903]

mines.c

@@ -1930,12 +1930,51 @@ static void obfuscate_bitmap(unsigned char *bmp, int bits, int decode)
     }
 }
 
+static char *describe_layout(char *grid, int area, int x, int y,
+                             int obfuscate)
+{
+    char *ret, *p;
+    unsigned char *bmp;
+    int i;
+
+    /*
+     * Set up the mine bitmap and obfuscate it.
+     */
+    bmp = snewn((area + 7) / 8, unsigned char);
+    memset(bmp, 0, (area + 7) / 8);
+    for (i = 0; i < area; i++) {
+        if (grid[i])
+            bmp[i / 8] |= 0x80 >> (i % 8);
+    }
+    if (obfuscate)
+        obfuscate_bitmap(bmp, area, FALSE);
+
+    /*
+     * Now encode the resulting bitmap in hex. We can work to
+     * nibble rather than byte granularity, since the obfuscation
+     * function guarantees to return a bit string of the same
+     * length as its input.
+     */
+    ret = snewn((area+3)/4 + 100, char);
+    p = ret + sprintf(ret, "%d,%d,%s", x, y,
+                      obfuscate ? "m" : "");   /* 'm' == masked */
+    for (i = 0; i < (area+3)/4; i++) {
+        int v = bmp[i/2];
+        if (i % 2 == 0)
+            v >>= 4;
+        *p++ = "0123456789abcdef"[v & 0xF];
+    }
+    *p = '\0';
+
+    sfree(bmp);
+
+    return ret;
+}
+
 static char *new_mine_layout(int w, int h, int n, int x, int y, int unique,
 			     random_state *rs, char **game_desc)
 {
-    char *grid, *ret, *p;
+    char *grid;
-    unsigned char *bmp;
-    int i, area;
 
 #ifdef TEST_OBFUSCATION
     static int tested_obfuscation = FALSE;
@@ -2002,39 +2041,8 @@ static char *new_mine_layout(int w, int h, int n, int x, int y, int unique,
 
     grid = minegen(w, h, n, x, y, unique, rs);
 
-    if (game_desc) {
+    if (game_desc)
-	/*
+        *game_desc = describe_layout(grid, w * h, x, y, TRUE);
-	 * Set up the mine bitmap and obfuscate it.
-	 */
-	area = w * h;
-	bmp = snewn((area + 7) / 8, unsigned char);
-	memset(bmp, 0, (area + 7) / 8);
-	for (i = 0; i < area; i++) {
-	    if (grid[i])
-		bmp[i / 8] |= 0x80 >> (i % 8);
-	}
-	obfuscate_bitmap(bmp, area, FALSE);
-
-	/*
-	 * Now encode the resulting bitmap in hex. We can work to
-	 * nibble rather than byte granularity, since the obfuscation
-	 * function guarantees to return a bit string of the same
-	 * length as its input.
-	 */
-	ret = snewn((area+3)/4 + 100, char);
-	p = ret + sprintf(ret, "%d,%d,m", x, y);   /* 'm' == masked */
-	for (i = 0; i < (area+3)/4; i++) {
-	    int v = bmp[i/2];
-	    if (i % 2 == 0)
-		v >>= 4;
-	    *p++ = "0123456789abcdef"[v & 0xF];
-	}
-	*p = '\0';
-
-	sfree(bmp);
-
-	*game_desc = ret;
-    }	
 
     return grid;
 }
@@ -3039,3 +3047,108 @@ const struct game thegame = {
     TRUE, game_timing_state,
     BUTTON_BEATS(LEFT_BUTTON, RIGHT_BUTTON),
 };
+
+#ifdef STANDALONE_OBFUSCATOR
+
+/*
+ * Vaguely useful stand-alone program which translates between
+ * obfuscated and clear Mines game descriptions. Pass in a game
+ * description on the command line, and if it's clear it will be
+ * obfuscated and vice versa. The output text should also be a
+ * valid game ID describing the same game. Like this:
+ *
+ * $ ./mineobfusc 9x9:4,4,mb071b49fbd1cb6a0d5868
+ * 9x9:4,4,004000007c00010022080
+ * $ ./mineobfusc 9x9:4,4,004000007c00010022080
+ * 9x9:4,4,mb071b49fbd1cb6a0d5868
+ *
+ * gcc -DSTANDALONE_OBFUSCATOR -o mineobfusc mines.c malloc.c random.c tree234.c
+ */
+
+#include <stdarg.h>
+
+void frontend_default_colour(frontend *fe, float *output) {}
+void draw_text(frontend *fe, int x, int y, int fonttype, int fontsize,
+               int align, int colour, char *text) {}
+void draw_rect(frontend *fe, int x, int y, int w, int h, int colour) {}
+void draw_line(frontend *fe, int x1, int y1, int x2, int y2, int colour) {}
+void draw_polygon(frontend *fe, int *coords, int npoints,
+                  int fill, int colour) {}
+void clip(frontend *fe, int x, int y, int w, int h) {}
+void unclip(frontend *fe) {}
+void start_draw(frontend *fe) {}
+void draw_update(frontend *fe, int x, int y, int w, int h) {}
+void end_draw(frontend *fe) {}
+void midend_supersede_game_desc(midend_data *me, char *desc) {}
+void status_bar(frontend *fe, char *text) {}
+
+void fatal(char *fmt, ...)
+{
+    va_list ap;
+
+    fprintf(stderr, "fatal error: ");
+
+    va_start(ap, fmt);
+    vfprintf(stderr, fmt, ap);
+    va_end(ap);
+
+    fprintf(stderr, "\n");
+    exit(1);
+}
+
+int main(int argc, char **argv)
+{
+    game_params *p;
+    game_state *s;
+    int recurse = TRUE;
+    char *id = NULL, *desc, *err;
+    int y, x;
+    int grade = FALSE;
+
+    while (--argc > 0) {
+        char *p = *++argv;
+	if (*p == '-') {
+            fprintf(stderr, "%s: unrecognised option `%s'\n", argv[0]);
+            return 1;
+        } else {
+            id = p;
+        }
+    }
+
+    if (!id) {
+        fprintf(stderr, "usage: %s <game_id>\n", argv[0]);
+        return 1;
+    }
+
+    desc = strchr(id, ':');
+    if (!desc) {
+        fprintf(stderr, "%s: game id expects a colon in it\n", argv[0]);
+        return 1;
+    }
+    *desc++ = '\0';
+
+    p = default_params();
+    decode_params(p, id);
+    err = validate_desc(p, desc);
+    if (err) {
+        fprintf(stderr, "%s: %s\n", argv[0], err);
+        return 1;
+    }
+    s = new_game(NULL, p, desc);
+
+    x = atoi(desc);
+    while (*desc && *desc != ',') desc++;
+    if (*desc) desc++;
+    y = atoi(desc);
+    while (*desc && *desc != ',') desc++;
+    if (*desc) desc++;
+
+    printf("%s:%s\n", id, describe_layout(s->layout->mines,
+                                          p->w * p->h,
+                                          x, y,
+                                          (*desc != 'm')));
+
+    return 0;
+}
+
+#endif