From c0136554ee870455bf1d1b527d7a724beda989b3 Mon Sep 17 00:00:00 2001
From: Carl Worth <cworth@raht.cworth.org>
Date: Thu, 28 Sep 2006 21:02:35 -0700
Subject: [PATCH] grid: Generalize to allow either 4x4 or 5x5 grid.

---
 grid.c  | 56 ++++++++++++++++++++++++++++++++++++++++----------------
 grid.h  | 14 ++++++++------
 grid4.c |  2 +-
 3 files changed, 49 insertions(+), 23 deletions(-)

diff --git a/grid.c b/grid.c
index eac8488..acfee21 100644
--- a/grid.c
+++ b/grid.c
@@ -20,14 +20,25 @@
 
 #include <string.h>
 #include <ctype.h>
+#include <assert.h>
 
-char *cube_faces[16] = {
+#define GRID_CUBES_MAX (GRID_SIZE_MAX * GRID_SIZE_MAX)
+
+char *cubes4[16] = {
     "aaeeng", "abbjoo", "achops", "affkps",
     "aoottw", "cimotu", "deilrx", "delrvy",
     "distty", "eeghnw", "eeinsu", "ehrtvw",
     "eiosst", "elrtty", "himnqu", "hlnnrz"
 };
 
+char *cubes5[25] = {
+    "aaafrs", "aaeeee", "aafirs", "adennn", "aeeeem",
+    "aeegmu", "aegmnn", "afirsy", "bjkqxz", "ccnstw",
+    "ceiilt", "ceilpt", "ceipst", "ddlnor", "dhhlor",
+    "dhhnot", "dhlnor", "eiiitt", "emottt", "ensssu",
+    "fiprsy", "gorrvw", "hiprry", "nootuw", "ooottu"
+};
+
 static int
 rand_within (int num_values)
 {
@@ -49,17 +60,30 @@ shuffle (int *array, int length)
 }
 
 void
-grid_init (grid_t *grid)
+grid_init (grid_t *grid, int size)
 {
     int i;
-    int cubes[16];
+    int cubes[GRID_CUBES_MAX];
+    char **cubes_source;
+    int num_cubes;
+
+    assert (size == 4 || size == 5);
+
+    grid->size = size;
+    num_cubes = size * size;
+
+    if (size == 4)
+	cubes_source = cubes4;
+    else 
+	cubes_source = cubes5;
 
-    for (i = 0; i < 16; i++)
+    for (i = 0; i < num_cubes; i++)
 	cubes[i] = i;
-    shuffle (cubes, 16);
+    shuffle (cubes, num_cubes);
  
-    for (i = 0; i < 16; i++)
-	grid->letters[i / 4][i % 4] = cube_faces[cubes[i]][rand_within(6)];
+    for (i = 0; i < num_cubes; i++)
+	grid->letters[i / grid->size][i % grid->size] =
+	    cubes_source[cubes[i]][rand_within(6)];
 }
 
 char *
@@ -69,8 +93,8 @@ grid_string (grid_t *grid)
     int x, y;
     char *s = grid->string;
 
-    for (y = 0; y < 4; y++) {
-	for (x = 0; x < 4; x++) {
+    for (y = 0; y < grid->size; y++) {
+	for (x = 0; x < grid->size; x++) {
 	    c = grid->letters[y][x];
 	    *s++ = ' ';
 	    *s++ = toupper (c);
@@ -87,12 +111,12 @@ grid_string (grid_t *grid)
     return grid->string;
 }
 
-#define SEEN_BIT(x, y) (1 << (4*(y)+(x)))
+#define SEEN_BIT(x, y) (1 << ((grid->size)*(y)+(x)))
 static void
 grid_enumerate (grid_t		*grid,
 		int		 x,
 		int		 y,
-		int16_t		 seen,
+		int32_t		 seen,
 		char		*word,
 		dict_cursor_t	 dict_cursor)
 {
@@ -102,8 +126,8 @@ grid_enumerate (grid_t		*grid,
     if (dict_cursor == DICT_CURSOR_NIL)
 	return;
 
-    if (x < 0 || x >= 4 ||
-	y < 0 || y >= 4 ||
+    if (x < 0 || x >= grid->size ||
+	y < 0 || y >= grid->size ||
 	seen & SEEN_BIT (x, y))
     {
 	return;
@@ -139,14 +163,14 @@ void
 grid_solve (grid_t *grid, dict_t *dict, dict_t *solution)
 {
     int x, y;
-    int16_t seen = 0;
+    int32_t seen = 0;
     char word[18];
 
     grid->results = solution;
 
     memset (word, '\0', 18);
 
-    for (y = 0; y < 4; y++)
-	for (x = 0; x < 4; x++)
+    for (y = 0; y < grid->size; y++)
+	for (x = 0; x < grid->size; x++)
 	    grid_enumerate (grid, x, y, seen, word, dict_root (dict));
 }
diff --git a/grid.h b/grid.h
index 3d200c7..e5b3d1e 100644
--- a/grid.h
+++ b/grid.h
@@ -21,25 +21,27 @@
 
 #include "dict.h"
 
+#define GRID_SIZE_MAX 5
 /* (  3 chars per cell
- *  x 4 cells per row
+ *  x GRID_SIZE_MAX cells per row
  *  + 1 newline per row
- * ) x 4 rows per grid
+ * ) x GRID_SIZE_MAX rows per grid
  *   + 1 terminator character
- * = 53
  */
-#define GRID_STRING_MAX 53
+#define GRID_STRING_MAX (((3 * GRID_SIZE_MAX + 1) * GRID_SIZE_MAX) + 1)
 
 typedef struct _grid {
-    char letters[4][4];
+    int size;
+    char letters[GRID_SIZE_MAX][GRID_SIZE_MAX];
     char string[GRID_STRING_MAX];
 
     /* Private, transient state used by enumerate */
     dict_t *results;
 } grid_t;
 
+/* size must be 4 or 5 */
 void
-grid_init (grid_t *grid);
+grid_init (grid_t *grid, int size);
 
 char *
 grid_string (grid_t *grid);
diff --git a/grid4.c b/grid4.c
index 96cb5e3..cd1e90b 100644
--- a/grid4.c
+++ b/grid4.c
@@ -36,7 +36,7 @@ main (void)
     dict_init (&dict);
     dict_add_words_from_file (&dict, "words.txt");
 
-    grid_init (&grid);
+    grid_init (&grid, 4);
 
     dict_init (&solution);
     grid_solve (&grid, &dict, &solution);
-- 
2.43.0