Stop putting dsfs in existing scratch int arrays.

I'm going to work towards turning 'dsf' into an opaque type, so that I
can improve its implementation without breaking clients. The first
step is to deal manually with puzzles that currently reuse a single
array of ints for multiple purposes, some of which are dsf and some
are not.

In divvy_rectangle_attempt, 'tmp' was used as an int array and later a
dsf, and I've made a new 'tmpdsf' to be the latter.

In Dominosa, solver->pc_scratch2 was sometimes a dsf, and now there's
a new solver->dsf_scratch.

In Map, parse_edge_list() needed a dsf internally and then never
exported it; it expected to be passed an array of 2*w*h ints and used
the second half as a dsf. Now it expects only w*h ints, and allocates
its own dsf internally, freeing it again before returning.

And in Tents, find_errors() was allocating a single block of 2*w*h
ints and using the second half of it as a dsf, apparently just to save
one malloc. Now we malloc and free the dsf separately.

1 files changed, 3 insertions, 2 deletions

diff --git a/tents.c b/tents.c
index 9f904f9..ca39401 100644
--- a/tents.c
+++ b/tents.c
@@ -2006,7 +2006,7 @@ static int *find_errors(const game_state *state, char *grid)
 {
     int w = state->p.w, h = state->p.h;
     int *ret = snewn(w*h + w + h, int);
-    int *tmp = snewn(w*h*2, int), *dsf = tmp + w*h;
+    int *tmp = snewn(w*h, int), *dsf;
     int x, y;
 
     /*
@@ -2223,7 +2223,7 @@ static int *find_errors(const game_state *state, char *grid)
      * all the tents in any component which has a smaller tree
      * count.
      */
-    dsf_init(dsf, w*h);
+    dsf = snew_dsf(w*h);
     /* Construct the equivalence classes. */
     for (y = 0; y < h; y++) {
 	for (x = 0; x < w-1; x++) {
@@ -2302,6 +2302,7 @@ static int *find_errors(const game_state *state, char *grid)
 #undef TENT
 
     sfree(tmp);
+    sfree(dsf);
     return ret;
 }