From d99a30cdb34b6de97a4aaa620a081273ccacd2a5 Mon Sep 17 00:00:00 2001
From: Sven Verdoolaege <skimo@kotnet.org>
Date: Mon, 1 Mar 2010 11:20:08 +0100
Subject: [PATCH] add isl_set_sample_point

---
 doc/user.pod      | 11 +++++++++++
 include/isl_set.h |  1 +
 isl_sample.c      | 39 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 51 insertions(+)

diff --git a/doc/user.pod b/doc/user.pod
index 666637a5..10d7af41 100644
--- a/doc/user.pod
+++ b/doc/user.pod
@@ -1094,6 +1094,17 @@ enumerating and return C<-1> as well.
 If the enumeration is performed successfully and to completion,
 then C<isl_set_foreach_point> returns C<0>.
 
+To obtain a single point of a set, use
+
+	__isl_give isl_point *isl_set_sample_point(
+		__isl_take isl_set *set);
+
+If C<set> does not contain any (integer) points, then the
+resulting point will be ``void'', a property that can be
+tested using
+
+	int isl_point_is_void(__isl_keep isl_point *pnt);
+
 =head2 Dependence Analysis
 
 C<isl> contains specialized functionality for performing
diff --git a/include/isl_set.h b/include/isl_set.h
index 146d99f5..a2216644 100644
--- a/include/isl_set.h
+++ b/include/isl_set.h
@@ -206,6 +206,7 @@ void isl_set_free(__isl_take isl_set *set);
 struct isl_set *isl_set_dup(struct isl_set *set);
 __isl_give isl_set *isl_set_from_basic_set(__isl_take isl_basic_set *bset);
 __isl_give isl_basic_set *isl_set_sample(__isl_take isl_set *set);
+__isl_give isl_point *isl_set_sample_point(__isl_take isl_set *set);
 __isl_give isl_set *isl_set_detect_equalities(__isl_take isl_set *set);
 __isl_give isl_basic_set *isl_set_affine_hull(__isl_take isl_set *set);
 __isl_give isl_basic_set *isl_set_convex_hull(__isl_take isl_set *set);
diff --git a/isl_sample.c b/isl_sample.c
index ed627531..f7c1c879 100644
--- a/isl_sample.c
+++ b/isl_sample.c
@@ -16,6 +16,7 @@
 #include "isl_equalities.h"
 #include "isl_tab.h"
 #include "isl_basis_reduction.h"
+#include <isl_point_private.h>
 
 static struct isl_vec *empty_sample(struct isl_basic_set *bset)
 {
@@ -1246,3 +1247,41 @@ __isl_give isl_basic_set *isl_set_sample(__isl_take isl_set *set)
 {
 	return (isl_basic_set *) isl_map_sample((isl_map *)set);
 }
+
+__isl_give isl_point *isl_basic_set_sample_point(__isl_take isl_basic_set *bset)
+{
+	isl_vec *vec;
+	isl_dim *dim;
+
+	dim = isl_basic_set_get_dim(bset);
+	bset = isl_basic_set_underlying_set(bset);
+	vec = isl_basic_set_sample_vec(bset);
+
+	return isl_point_alloc(dim, vec);
+}
+
+__isl_give isl_point *isl_set_sample_point(__isl_take isl_set *set)
+{
+	int i;
+	isl_point *pnt;
+
+	if (!set)
+		return NULL;
+
+	for (i = 0; i < set->n; ++i) {
+		pnt = isl_basic_set_sample_point(isl_basic_set_copy(set->p[i]));
+		if (!pnt)
+			goto error;
+		if (!isl_point_is_void(pnt))
+			break;
+		isl_point_free(pnt);
+	}
+	if (i == set->n)
+		pnt = isl_point_void(isl_set_get_dim(set));
+
+	isl_set_free(set);
+	return pnt;
+error:
+	isl_set_free(set);
+	return NULL;
+}
-- 
2.11.4.GIT