fairland: Represent sector ownership more efficiently

Replace own[x][y] by own[XYOFFSET(x, y)], and narrow the element type
from int to short.  Takes a fourth the space.

Signed-off-by: Markus Armbruster <armbru@pond.sub.org>

diff --git a/src/util/fairland.c b/src/util/fairland.c
index 30c66297a687add58c0f3a8e92a42b9c24b68ed2..8c12a8c74b0368d7912028ad5a5bbc29450cf778 100644 (file)
--- a/src/util/fairland.c
+++ b/src/util/fairland.c
@@ -230,7 +230,11 @@ static int *isecs;
 
 static int *capx, *capy;       /* location of the nc capitals */
 
-static int **own;              /* owner of the sector.  -1 means water */
+/*
+ * Island at x, y
+ * own[XYOFFSET(x, y)] is x,y's island number, -1 if water.
+ */
+static short *own;
 
 /*
  * Adjacent land sectors
@@ -579,7 +583,7 @@ allocate_memory(void)
 
     capx = calloc(nc, sizeof(int));
     capy = calloc(nc, sizeof(int));
-    own = calloc(WORLD_X, sizeof(int *));
+    own = malloc(WORLD_SZ() * sizeof(*own));
     adj_land = malloc(WORLD_SZ() * sizeof(*adj_land));
     elev = calloc(WORLD_SZ(), sizeof(*elev));
     xzone = malloc(WORLD_SZ() * sizeof(*xzone));
@@ -587,9 +591,6 @@ allocate_memory(void)
     closest = malloc(WORLD_SZ() * sizeof(*closest));
     distance = malloc(WORLD_SZ() * sizeof(*distance));
     bfs_queue = malloc(WORLD_SZ() * sizeof(*bfs_queue));
-    for (i = 0; i < WORLD_X; ++i) {
-       own[i] = calloc(WORLD_Y, sizeof(int));
-    }
     sectx = calloc(nc + ni, sizeof(int *));
     secty = calloc(nc + ni, sizeof(int *));
     isecs = calloc(nc + ni, sizeof(int));
@@ -607,13 +608,10 @@ allocate_memory(void)
 static void
 init(void)
 {
-    int i, j;
+    int i;
 
-    for (i = 0; i < WORLD_X; ++i) {
-       for (j = 0; j < WORLD_Y; ++j) {
-           own[i][j] = -1;
-       }
-    }
+    for (i = 0; i < WORLD_SZ(); i++)
+       own[i] = -1;
     memset(adj_land, 0, WORLD_SZ() * sizeof(*adj_land));
 }
 
@@ -1004,13 +1002,14 @@ is_in_sphere(int c, int x, int y)
 static int
 can_grow_at(int c, int x, int y)
 {
-    return own[x][y] == -1 && xzone_ok(c, x, y) && is_in_sphere(c, x, y);
+    return own[XYOFFSET(x, y)] == -1 && xzone_ok(c, x, y)
+       && is_in_sphere(c, x, y);
 }
 
 static void
 adj_land_update(int x, int y)
 {
-    int is_land = own[x][y] != -1;
+    int is_land = own[XYOFFSET(x, y)] != -1;
     int dir, nx, ny, noff;
 
     for (dir = DIR_FIRST; dir <= DIR_LAST; dir++) {
@@ -1027,12 +1026,14 @@ adj_land_update(int x, int y)
 static void
 add_sector(int c, int x, int y)
 {
-    assert(own[x][y] == -1);
+    int off = XYOFFSET(x, y);
+
+    assert(own[off] == -1);
     xzone_around_sector(c, x, y, c < nc ? di : DISTINCT_ISLANDS ? id : 0);
     sectx[c][isecs[c]] = x;
     secty[c][isecs[c]] = y;
     isecs[c]++;
-    own[x][y] = c;
+    own[off] = c;
     adj_land_update(x, y);
 }
 
@@ -1251,7 +1252,7 @@ grow_islands(void)
                    assert(isecs[c + j] == secs);
                    x = sectx[c + j][secs];
                    y = secty[c + j][secs];
-                   own[x][y] = -1;
+                   own[XYOFFSET(x, y)] = -1;
                    adj_land_update(x, y);
                }
            }
@@ -1308,7 +1309,7 @@ elevate_prep(void)
     while (n > 0) {
        off0 = roll0(WORLD_SZ());
        sctoff2xy(&x0, &y0, off0);
-       if (own[x0][y0] == -1) {
+       if (own[off0] == -1) {
            r = roll(MIN(3, distance[off0]));
            sign = -1;
        } else {
@@ -1442,7 +1443,7 @@ write_sects(void)
            sct->sct_elev = elev[sct->sct_uid];
            sct->sct_type = elev_to_sct_type(sct->sct_elev);
            sct->sct_newtype = sct->sct_type;
-           sct->sct_dterr = own[sct->sct_x][y] + 1;
+           sct->sct_dterr = own[sct->sct_uid] + 1;
            sct->sct_coastal = is_coastal(sct->sct_x, sct->sct_y);
            add_resources(sct);
        }
@@ -1466,7 +1467,7 @@ output(void)
            for (sx = -WORLD_X / 2 + y % 2; sx < WORLD_X / 2; sx += 2) {
                x = XNORM(sx);
                off = XYOFFSET(x, y);
-               c = own[x][y];
+               c = own[off];
                type = elev_to_sct_type(elev[off]);
                if (type == SCT_WATER)
                    printf(". ");
@@ -1488,25 +1489,26 @@ output(void)
 }
 
 /*
- * Print a map to help visualize own[][].
+ * Print a map to help visualize own[].
  * This is for debugging.
  */
 void
 print_own_map(void)
 {
-    int sx, sy, x, y;
+    int sx, sy, x, y, off;
 
     for (sy = -WORLD_Y / 2; sy < WORLD_Y / 2; sy++) {
        y = YNORM(sy);
        printf("%4d ", sy);
        for (sx = -WORLD_X / 2; sx < WORLD_X / 2; sx++) {
            x = XNORM(sx);
+           off = XYOFFSET(x, y);
            if ((x + y) & 1)
                putchar(' ');
-           else if (own[x][y] == -1)
+           else if (own[off] == -1)
                putchar('.');
            else
-               putchar(numletter[own[x][y] % 62]);
+               putchar(numletter[own[off] % 62]);
        }
        putchar('\n');
     }
@@ -1567,12 +1569,12 @@ print_xzone_map(void)
            off = XYOFFSET(x, y);
            if ((x + y) & 1)
                putchar(' ');
-           else if (own[x][y] >= 0)
+           else if (own[off] >= 0)
                putchar('-');
            else if (xzone[off] >= 0)
                putchar(numletter[xzone[off] % 62]);
            else {
-               assert(own[x][y] == -1);
+               assert(own[off] == -1);
                putchar(xzone[off] == -1 ? '.' : '!');
            }
        }
@@ -1600,7 +1602,7 @@ print_closest_map(void)
            else if (closest[off] == (natid)-1)
                putchar('.');
            else if (!distance[off]) {
-               assert(closest[off] == own[x][y]);
+               assert(closest[off] == own[off]);
                putchar('-');
            } else {
                putchar(numletter[closest[off] % 62]);
@@ -1626,7 +1628,7 @@ print_distance_map(void)
            else if (closest[off] == (natid)-1)
                putchar('.');
            else if (!distance[off]) {
-               assert(closest[off] == own[x][y]);
+               assert(closest[off] == own[off]);
                putchar('-');
            } else {
                putchar(numletter[distance[off] % 62]);