add isl_set_foreach_orthant

Signed-off-by: Sven Verdoolaege <skimo@kotnet.org>

diff --git a/isl_map.c b/isl_map.c
index 44f213d..d2b64c8 100644 (file)
--- a/isl_map.c
+++ b/isl_map.c
@@ -5642,6 +5642,70 @@ error:
        return NULL;
 }
 
+static int foreach_orthant(__isl_take isl_set *set, int *signs, int first,
+       int len, int (*fn)(__isl_take isl_set *orthant, int *signs, void *user),
+       void *user)
+{
+       isl_set *half;
+
+       if (!set)
+               return -1;
+       if (isl_set_fast_is_empty(set)) {
+               isl_set_free(set);
+               return 0;
+       }
+       if (first == len)
+               return fn(set, signs, user);
+
+       signs[first] = 1;
+       half = isl_set_from_basic_set(nonneg_halfspace(isl_set_get_dim(set),
+                                                       1 + first));
+       half = isl_set_intersect(half, isl_set_copy(set));
+       if (foreach_orthant(half, signs, first + 1, len, fn, user) < 0)
+               goto error;
+
+       signs[first] = -1;
+       half = isl_set_from_basic_set(neg_halfspace(isl_set_get_dim(set),
+                                                       1 + first));
+       half = isl_set_intersect(half, set);
+       return foreach_orthant(half, signs, first + 1, len, fn, user);
+error:
+       isl_set_free(set);
+       return -1;
+}
+
+/* Call "fn" on the intersections of "set" with each of the orthants
+ * (except for obviously empty intersections).  The orthant is identified
+ * by the signs array, with each entry having value 1 or -1 according
+ * to the sign of the corresponding variable.
+ */
+int isl_set_foreach_orthant(__isl_keep isl_set *set,
+       int (*fn)(__isl_take isl_set *orthant, int *signs, void *user),
+       void *user)
+{
+       unsigned nparam;
+       unsigned nvar;
+       int *signs;
+       int r;
+
+       if (!set)
+               return -1;
+       if (isl_set_fast_is_empty(set))
+               return 0;
+
+       nparam = isl_set_dim(set, isl_dim_param);
+       nvar = isl_set_dim(set, isl_dim_set);
+
+       signs = isl_alloc_array(set->ctx, int, nparam + nvar);
+
+       r = foreach_orthant(isl_set_copy(set), signs, 0, nparam + nvar,
+                           fn, user);
+
+       free(signs);
+
+       return r;
+}
+
 int isl_set_is_equal(struct isl_set *set1, struct isl_set *set2)
 {
        return isl_map_is_equal((struct isl_map *)set1, (struct isl_map *)set2);

diff --git a/isl_map_private.h b/isl_map_private.h
index 409025c..5066be2 100644 (file)
--- a/isl_map_private.h
+++ b/isl_map_private.h
@@ -193,6 +193,9 @@ int isl_set_contains_point(__isl_keep isl_set *set, __isl_keep isl_point *point)
 
 int isl_basic_set_vars_get_sign(__isl_keep isl_basic_set *bset,
        unsigned first, unsigned n, int *signs);
+int isl_set_foreach_orthant(__isl_keep isl_set *set,
+       int (*fn)(__isl_take isl_set *orthant, int *signs, void *user),
+       void *user);
 
 int isl_basic_set_add_div_constraints_var(__isl_keep isl_basic_set *bset,
        unsigned pos, isl_int *div);