Make *allocx() size class overflow behavior defined.

Limit supported size and alignment to HUGE_MAXCLASS, which in turn is
now limited to be less than PTRDIFF_MAX.

This resolves #278 and #295.

1 files changed, 24 insertions, 1 deletions

diff --git a/test/unit/size_classes.c b/test/unit/size_classes.c
index d3aaebd..3a2126f 100644
--- a/test/unit/size_classes.c
+++ b/test/unit/size_classes.c
@@ -80,10 +80,33 @@ TEST_BEGIN(test_size_classes)
 }
 TEST_END
 
+TEST_BEGIN(test_overflow)
+{
+	size_t max_size_class;
+
+	max_size_class = get_max_size_class();
+
+	assert_u_ge(size2index(max_size_class+1), NSIZES,
+	    "size2index() should return >= NSIZES on overflow");
+	assert_u_ge(size2index(PTRDIFF_MAX+1), NSIZES,
+	    "size2index() should return >= NSIZES on overflow");
+	assert_u_ge(size2index(SIZE_T_MAX), NSIZES,
+	    "size2index() should return >= NSIZES on overflow");
+
+	assert_zu_gt(s2u(max_size_class+1), HUGE_MAXCLASS,
+	    "s2u() should return > HUGE_MAXCLASS for unsupported size");
+	assert_zu_gt(s2u(PTRDIFF_MAX+1), HUGE_MAXCLASS,
+	    "s2u() should return > HUGE_MAXCLASS for unsupported size");
+	assert_zu_eq(s2u(SIZE_T_MAX), 0,
+	    "s2u() should return 0 on overflow");
+}
+TEST_END
+
 int
 main(void)
 {
 
 	return (test(
-	    test_size_classes));
+	    test_size_classes,
+	    test_overflow));
 }