Giant const patch of doom: add a 'const' to every parameter in every

puzzle backend function which ought to have it, and propagate those
consts through to per-puzzle subroutines as needed.

I've recently had to do that to a few specific parameters which were
being misused by particular puzzles (r9657, r9830), which suggests
that it's probably a good idea to do the whole lot pre-emptively
before the next such problem shows up.

[originally from svn r9832]
[r9657 == 3b250baa02a7332510685948bf17576c397b8ceb]
[r9830 == 0b93de904a98f119b1a95d3a53029f1ed4bfb9b3]

1 files changed, 57 insertions, 39 deletions

diff --git a/twiddle.c b/twiddle.c
index 08ef792..a1d32cd 100644
--- a/twiddle.c
+++ b/twiddle.c
@@ -70,7 +70,7 @@ static void free_params(game_params *params)
     sfree(params);
 }
 
-static game_params *dup_params(game_params *params)
+static game_params *dup_params(const game_params *params)
 {
     game_params *ret = snew(game_params);
     *ret = *params;		       /* structure copy */
@@ -133,7 +133,7 @@ static void decode_params(game_params *ret, char const *string)
     }
 }
 
-static char *encode_params(game_params *params, int full)
+static char *encode_params(const game_params *params, int full)
 {
     char buf[256];
     sprintf(buf, "%dx%dn%d%s%s", params->w, params->h, params->n,
@@ -146,7 +146,7 @@ static char *encode_params(game_params *params, int full)
     return dupstr(buf);
 }
 
-static config_item *game_configure(game_params *params)
+static config_item *game_configure(const game_params *params)
 {
     config_item *ret;
     char buf[80];
@@ -195,7 +195,7 @@ static config_item *game_configure(game_params *params)
     return ret;
 }
 
-static game_params *custom_params(config_item *cfg)
+static game_params *custom_params(const config_item *cfg)
 {
     game_params *ret = snew(game_params);
 
@@ -209,7 +209,7 @@ static game_params *custom_params(config_item *cfg)
     return ret;
 }
 
-static char *validate_params(game_params *params, int full)
+static char *validate_params(const game_params *params, int full)
 {
     if (params->n < 2)
 	return "Rotating block size must be at least two";
@@ -430,9 +430,9 @@ static char *new_game_desc(const game_params *params, random_state *rs,
     return ret;
 }
 
-static char *validate_desc(const game_params *params, char *desc)
+static char *validate_desc(const game_params *params, const char *desc)
 {
-    char *p;
+    const char *p;
     int w = params->w, h = params->h, wh = w*h;
     int i;
 
@@ -459,12 +459,13 @@ static char *validate_desc(const game_params *params, char *desc)
     return NULL;
 }
 
-static game_state *new_game(midend *me, game_params *params, char *desc)
+static game_state *new_game(midend *me, const game_params *params,
+                            const char *desc)
 {
     game_state *state = snew(game_state);
     int w = params->w, h = params->h, n = params->n, wh = w*h;
     int i;
-    char *p;
+    const char *p;
 
     state->w = w;
     state->h = h;
@@ -499,7 +500,7 @@ static game_state *new_game(midend *me, game_params *params, char *desc)
     return state;
 }
 
-static game_state *dup_game(game_state *state)
+static game_state *dup_game(const game_state *state)
 {
     game_state *ret = snew(game_state);
 
@@ -539,18 +540,18 @@ static int compare_int(const void *av, const void *bv)
 	return 0;
 }
 
-static char *solve_game(game_state *state, game_state *currstate,
-			char *aux, char **error)
+static char *solve_game(const game_state *state, const game_state *currstate,
+                        const char *aux, char **error)
 {
     return dupstr("S");
 }
 
-static int game_can_format_as_text_now(game_params *params)
+static int game_can_format_as_text_now(const game_params *params)
 {
     return TRUE;
 }
 
-static char *game_text_format(game_state *state)
+static char *game_text_format(const game_state *state)
 {
     char *ret, *p, buf[80];
     int i, x, y, col, o, maxlen;
@@ -602,7 +603,7 @@ struct game_ui {
     int cur_visible;
 };
 
-static game_ui *new_ui(game_state *state)
+static game_ui *new_ui(const game_state *state)
 {
     game_ui *ui = snew(game_ui);
 
@@ -618,17 +619,17 @@ static void free_ui(game_ui *ui)
     sfree(ui);
 }
 
-static char *encode_ui(game_ui *ui)
+static char *encode_ui(const game_ui *ui)
 {
     return NULL;
 }
 
-static void decode_ui(game_ui *ui, char *encoding)
+static void decode_ui(game_ui *ui, const char *encoding)
 {
 }
 
-static void game_changed_state(game_ui *ui, game_state *oldstate,
-                               game_state *newstate)
+static void game_changed_state(game_ui *ui, const game_state *oldstate,
+                               const game_state *newstate)
 {
 }
 
@@ -640,8 +641,9 @@ struct game_drawstate {
     int cur_x, cur_y;
 };
 
-static char *interpret_move(game_state *state, game_ui *ui, const game_drawstate *ds,
-			    int x, int y, int button)
+static char *interpret_move(const game_state *state, game_ui *ui,
+                            const game_drawstate *ds,
+                            int x, int y, int button)
 {
     int w = state->w, h = state->h, n = state->n /* , wh = w*h */;
     char buf[80];
@@ -731,7 +733,7 @@ static char *interpret_move(game_state *state, game_ui *ui, const game_drawstate
     return dupstr(buf);
 }
 
-static game_state *execute_move(game_state *from, char *move)
+static game_state *execute_move(const game_state *from, const char *move)
 {
     game_state *ret;
     int w = from->w, h = from->h, n = from->n, wh = w*h;
@@ -782,8 +784,8 @@ static game_state *execute_move(game_state *from, char *move)
  * Drawing routines.
  */
 
-static void game_compute_size(game_params *params, int tilesize,
-			      int *x, int *y)
+static void game_compute_size(const game_params *params, int tilesize,
+                              int *x, int *y)
 {
     /* Ick: fake up `ds->tilesize' for macro expansion purposes */
     struct { int tilesize; } ads, *ds = &ads;
@@ -794,7 +796,7 @@ static void game_compute_size(game_params *params, int tilesize,
 }
 
 static void game_set_size(drawing *dr, game_drawstate *ds,
-			  game_params *params, int tilesize)
+                          const game_params *params, int tilesize)
 {
     ds->tilesize = tilesize;
 }
@@ -822,7 +824,7 @@ static float *game_colours(frontend *fe, int *ncolours)
     return ret;
 }
 
-static game_drawstate *game_new_drawstate(drawing *dr, game_state *state)
+static game_drawstate *game_new_drawstate(drawing *dr, const game_state *state)
 {
     struct game_drawstate *ds = snew(struct game_drawstate);
     int i;
@@ -872,7 +874,7 @@ static void rotate(int *xy, struct rotation *rot)
 #define CUR_BOTTOM      4
 #define CUR_LEFT        8
 
-static void draw_tile(drawing *dr, game_drawstate *ds, game_state *state,
+static void draw_tile(drawing *dr, game_drawstate *ds, const game_state *state,
                       int x, int y, int tile, int flash_colour,
                       struct rotation *rot, unsigned cedges)
 {
@@ -1053,14 +1055,29 @@ static int highlight_colour(float angle)
     return colours[(int)((angle + 2*PI) / (PI/16)) & 31];
 }
 
-static float game_anim_length(game_state *oldstate, game_state *newstate,
-			      int dir, game_ui *ui)
+static float game_anim_length_real(const game_state *oldstate,
+                                   const game_state *newstate, int dir,
+                                   const game_ui *ui)
 {
+    /*
+     * Our game_anim_length doesn't need to modify its game_ui, so
+     * this is the real function which declares ui as const. We must
+     * wrap this for the backend structure with a version that has ui
+     * non-const, but we still need this version to call from within
+     * game_redraw which only has a const ui available.
+     */
     return (float)(ANIM_PER_BLKSIZE_UNIT * sqrt(newstate->n-1));
 }
 
-static float game_flash_length(game_state *oldstate, game_state *newstate,
-			       int dir, game_ui *ui)
+static float game_anim_length(const game_state *oldstate,
+                              const game_state *newstate, int dir, game_ui *ui)
+{
+    return game_anim_length_real(oldstate, newstate, dir, ui);
+
+}
+
+static float game_flash_length(const game_state *oldstate,
+                               const game_state *newstate, int dir, game_ui *ui)
 {
     if (!oldstate->completed && newstate->completed &&
 	!oldstate->used_solve && !newstate->used_solve)
@@ -1069,14 +1086,15 @@ static float game_flash_length(game_state *oldstate, game_state *newstate,
         return 0.0F;
 }
 
-static int game_status(game_state *state)
+static int game_status(const game_state *state)
 {
     return state->completed ? +1 : 0;
 }
 
-static void game_redraw(drawing *dr, game_drawstate *ds, game_state *oldstate,
-			game_state *state, int dir, game_ui *ui,
-			float animtime, float flashtime)
+static void game_redraw(drawing *dr, game_drawstate *ds,
+                        const game_state *oldstate, const game_state *state,
+                        int dir, const game_ui *ui,
+                        float animtime, float flashtime)
 {
     int i, bgcolour;
     struct rotation srot, *rot;
@@ -1133,7 +1151,7 @@ static void game_redraw(drawing *dr, game_drawstate *ds, game_state *oldstate,
      */
     if (oldstate) {
 	float angle;
-	float anim_max = game_anim_length(oldstate, state, dir, ui);
+	float anim_max = game_anim_length_real(oldstate, state, dir, ui);
 
 	if (dir > 0) {
 	    lastx = state->lastx;
@@ -1243,16 +1261,16 @@ static void game_redraw(drawing *dr, game_drawstate *ds, game_state *oldstate,
     }
 }
 
-static int game_timing_state(game_state *state, game_ui *ui)
+static int game_timing_state(const game_state *state, game_ui *ui)
 {
     return TRUE;
 }
 
-static void game_print_size(game_params *params, float *x, float *y)
+static void game_print_size(const game_params *params, float *x, float *y)
 {
 }
 
-static void game_print(drawing *dr, game_state *state, int tilesize)
+static void game_print(drawing *dr, const game_state *state, int tilesize)
 {
 }