[Freeciv-Dev] (PR#8959) remove CAR_DIR_D[XY]

["Jason Short" <jdorje@xxxxxxxxxxxxxxxxxxxxx>]

<URL: http://rt.freeciv.org/Ticket/Display.html?id=8959 >

This patch removes CAR_DIR_DX and CAR_DIR_DY.

There are several reasons for doing this:

- It's cleaner; less code.

- The "cardinal" directions don't have to be hard-coded, allowing them 
to be changed.  (Although it's possible to change the array at runtime 
this method is much easier.)

The only drawback is it is potentially slower.  I don't have numbers on 
this but I suspect the difference is unmeasurable (and I'm quite sure it 
would be if DIR_IS_CARDINAL were inlined).  (The order of iteration may 
be changed, perhaps causing a difference in savegames.  So it might be 
hard to measure.)

jason

Index: common/map.c
===================================================================
RCS file: /home/freeciv/CVS/freeciv/common/map.c,v
retrieving revision 1.169
diff -u -r1.169 map.c
--- common/map.c        6 Jun 2004 20:45:27 -0000       1.169
+++ common/map.c        11 Jun 2004 18:39:47 -0000
@@ -42,10 +42,6 @@
 const int DIR_DX[8] = { -1, 0, 1, -1, 1, -1, 0, 1 };
 const int DIR_DY[8] = { -1, -1, -1, 0, 0, 1, 1, 1 };
 
-/* like DIR_DX[] and DIR_DY[], only cartesian */
-const int CAR_DIR_DX[4] = {1, 0, -1, 0};
-const int CAR_DIR_DY[4] = {0, 1, 0, -1};
-
 /* Names of specials.
  * (These must correspond to enum tile_special_type in terrain.h.)
  */
Index: common/map.h
===================================================================
RCS file: /home/freeciv/CVS/freeciv/common/map.h,v
retrieving revision 1.187
diff -u -r1.187 map.h
--- common/map.h        6 Jun 2004 20:45:27 -0000       1.187
+++ common/map.h        11 Jun 2004 18:39:48 -0000
@@ -609,27 +609,13 @@
 extern const int DIR_DX[8];
 extern const int DIR_DY[8];
 
-/* like DIR_DX[] and DIR_DY[], only cartesian */
-extern const int CAR_DIR_DX[4];
-extern const int CAR_DIR_DY[4];
-
-#define cartesian_adjacent_iterate(x, y, IAC_x, IAC_y)                        \
-{                                                                             \
-  int IAC_i;                                                                  \
-  int IAC_x, IAC_y;                                                           \
-  bool _is_border = IS_BORDER_MAP_POS(x, y, 1);                               \
-  CHECK_MAP_POS(x, y);                                                        \
-  for (IAC_i = 0; IAC_i < 4; IAC_i++) {                                       \
-    IAC_x = x + CAR_DIR_DX[IAC_i];                                            \
-    IAC_y = y + CAR_DIR_DY[IAC_i];                                            \
-                                                                              \
-    if (_is_border && !normalize_map_pos(&IAC_x, &IAC_y)) {                   \
-      continue;                                                               \
-    }
-
-#define cartesian_adjacent_iterate_end                                        \
-  }                                                                           \
-}
+#define cartesian_adjacent_iterate(x, y, center_x, center_y)               \
+  adjc_dir_iterate(x, y, center_x, center_y, _dir) {                       \
+    if (DIR_IS_CARDINAL(_dir)) {
+
+#define cartesian_adjacent_iterate_end                                      \
+    }                                                                      \
+  } adjc_dir_iterate_end;
 
 /* Used for network transmission; do not change. */
 #define MAP_TILE_OWNER_NULL     MAX_UINT8
Index: server/mapgen.c
===================================================================
RCS file: /home/freeciv/CVS/freeciv/server/mapgen.c,v
retrieving revision 1.136
diff -u -r1.136 mapgen.c
--- server/mapgen.c     6 Jun 2004 20:45:27 -0000       1.136
+++ server/mapgen.c     11 Jun 2004 18:39:48 -0000
@@ -832,10 +832,9 @@
     for (func_num = 0; func_num < NUM_TEST_FUNCTIONS; func_num++) {
       int best_val = -1;
       /* first get the tile values for the function */
-      for (dir = 0; dir < 4; dir++) {
-       int x1 = x + CAR_DIR_DX[dir];
-       int y1 = y + CAR_DIR_DY[dir];
-       if (normalize_map_pos(&x1, &y1)
+      adjc_dir_iterate(x, y, x1, y1, dir) {
+       if (DIR_IS_CARDINAL(dir)
+           && normalize_map_pos(&x1, &y1)
            && rd_direction_is_valid[dir]) {
          rd_comparison_val[dir] = (test_funcs[func_num].func) (x1, y1);
          if (best_val == -1) {
@@ -844,22 +843,21 @@
            best_val = MIN(rd_comparison_val[dir], best_val);
          }
        }
-      }
+      } adjc_dir_iterate_end;
       assert(best_val != -1);
 
       /* should we abort? */
       if (best_val > 0 && test_funcs[func_num].fatal) return FALSE;
 
       /* mark the less attractive directions as invalid */
-      for (dir = 0; dir < 4; dir++) {
-       int x1 = x + CAR_DIR_DX[dir];
-       int y1 = y + CAR_DIR_DY[dir];
-       if (normalize_map_pos(&x1, &y1)
+      adjc_dir_iterate(x, y, x1, y1, dir) {
+       if (DIR_IS_CARDINAL(dir)
+           && normalize_map_pos(&x1, &y1)
            && rd_direction_is_valid[dir]) {
          if (rd_comparison_val[dir] != best_val)
            rd_direction_is_valid[dir] = FALSE;
        }
-      }
+      } adjc_dir_iterate_end;
     }
 
     /* Directions evaluated with all functions. Now choose the best
@@ -873,16 +871,15 @@
     case 0:
       return FALSE; /* river aborted */
     case 1:
-      for (dir = 0; dir < 4; dir++) {
-       int x1 = x + CAR_DIR_DX[dir];
-       int y1 = y + CAR_DIR_DY[dir];
-       if (normalize_map_pos(&x1, &y1)
+      adjc_dir_iterate(x, y, x1, y1, dir) {
+       if (DIR_IS_CARDINAL(dir)
+           && normalize_map_pos(&x1, &y1)
            && rd_direction_is_valid[dir]) {
          river_blockmark(x, y);
          x = x1;
          y = y1;
        }
-      }
+      } adjc_dir_iterate_end;
       break;
     default:
       /* More than one possible direction; Let the random number
@@ -893,10 +890,9 @@
       freelog(LOG_DEBUG, "mapgen.c: direction: %d", direction);
 
       /* Find the direction that the random number generator selected. */
-      for (dir = 0; dir < 4; dir++) {
-       int x1 = x + CAR_DIR_DX[dir];
-       int y1 = y + CAR_DIR_DY[dir];
-       if (normalize_map_pos(&x1, &y1)
+      adjc_dir_iterate(x, y, x1, y1, dir) {
+       if (DIR_IS_CARDINAL(dir)
+           && normalize_map_pos(&x1, &y1)
            && rd_direction_is_valid[dir]) {
          if (direction > 0) direction--;
          else {
@@ -906,7 +902,7 @@
            break;
          }
        }
-      }
+      } adjc_dir_iterate_end;
       break;
     } /* end switch (rd_number_of_directions()) */