+
+/* Check if dimension dim belongs to a residue class
+ * i_dim \equiv r mod m
+ * with m != 1 and if so return m in *modulo and r in *residue.
+ * As a special case, when i_dim has a fixed value v, then
+ * *modulo is set to 0 and *residue to v.
+ *
+ * If i_dim does not belong to such a residue class, then *modulo
+ * is set to 1 and *residue is set to 0.
+ */
+int isl_set_dim_residue_class(struct isl_set *set,
+ int pos, isl_int *modulo, isl_int *residue)
+{
+ isl_int m;
+ isl_int r;
+ int i;
+
+ if (!set || !modulo || !residue)
+ return -1;
+
+ if (set->n == 0) {
+ isl_int_set_si(*modulo, 0);
+ isl_int_set_si(*residue, 0);
+ return 0;
+ }
+
+ if (isl_basic_set_dim_residue_class(set->p[0], pos, modulo, residue)<0)
+ return -1;
+
+ if (set->n == 1)
+ return 0;
+
+ if (isl_int_is_one(*modulo))
+ return 0;
+
+ isl_int_init(m);
+ isl_int_init(r);
+
+ for (i = 1; i < set->n; ++i) {
+ if (isl_basic_set_dim_residue_class(set->p[i], pos, &m, &r) < 0)
+ goto error;
+ isl_int_gcd(*modulo, *modulo, m);
+ isl_int_sub(m, *residue, r);
+ isl_int_gcd(*modulo, *modulo, m);
+ if (!isl_int_is_zero(*modulo))
+ isl_int_fdiv_r(*residue, *residue, *modulo);
+ if (isl_int_is_one(*modulo))
+ break;
+ }
+
+ isl_int_clear(m);
+ isl_int_clear(r);
+
+ return 0;
+error:
+ isl_int_clear(m);
+ isl_int_clear(r);
+ return -1;
+}
+
+/* Check if dimension "dim" belongs to a residue class
+ * i_dim \equiv r mod m
+ * with m != 1 and if so return m in *modulo and r in *residue.
+ * As a special case, when i_dim has a fixed value v, then
+ * *modulo is set to 0 and *residue to v.
+ *
+ * If i_dim does not belong to such a residue class, then *modulo
+ * is set to 1 and *residue is set to 0.
+ */
+int isl_set_dim_residue_class_val(__isl_keep isl_set *set,
+ int pos, __isl_give isl_val **modulo, __isl_give isl_val **residue)
+{
+ *modulo = NULL;
+ *residue = NULL;
+ if (!set)
+ return -1;
+ *modulo = isl_val_alloc(isl_set_get_ctx(set));
+ *residue = isl_val_alloc(isl_set_get_ctx(set));
+ if (!*modulo || !*residue)
+ goto error;
+ if (isl_set_dim_residue_class(set, pos,
+ &(*modulo)->n, &(*residue)->n) < 0)
+ goto error;
+ isl_int_set_si((*modulo)->d, 1);
+ isl_int_set_si((*residue)->d, 1);
+ return 0;
+error:
+ isl_val_free(*modulo);
+ isl_val_free(*residue);
+ return -1;
+}