test: Add arc-infinite-loop

The handling of angles above 2pi in cairo_arc is not very solid and is
basically untested.

This test should ensure that huge inputs don't hang cairo.

test/Makefile.am

@@ -154,6 +154,7 @@ REFERENCE_IMAGES = \
 	alpha-similar.svg.argb32.xfail.png \
 	alpha-similar.svg.rgb24.xfail.png \
 	api-special-cases.ref.png \
+	arc-infinite-loop.ref.png \
 	arc-looping-dash.image16.ref.png \
 	arc-looping-dash.ps.ref.png \
 	arc-looping-dash.ref.png \

test/Makefile.sources

@@ -9,6 +9,7 @@ test_sources = \
 	a8-mask.c					\
 	aliasing.c					\
 	alpha-similar.c					\
+	arc-infinite-loop.c				\
 	arc-looping-dash.c				\
 	api-special-cases.c				\
 	big-line.c					\

test/arc-infinite-loop.c

@@ -0,0 +1,59 @@
+/* -*- Mode: c; c-basic-offset: 4; indent-tabs-mode: t; tab-width: 8; -*- */
+/*
+ * Copyright 2010 Andrea Canciani
+ *
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation
+ * files (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy,
+ * modify, merge, publish, distribute, sublicense, and/or sell copies
+ * of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ * Author: Andrea Canciani <ranma42@gmail.com>
+ */
+
+#include "cairo-test.h"
+#include <float.h>
+
+#define SIZE 8
+
+/*
+  cairo_arc can hang in an infinite loop if given huge (so big that
+  adding/subtracting 4*M_PI to them doesn't change the value because
+  of floating point rounding).
+
+  The purpose of this test is to check that cairo doesn't hang or crash.
+*/
+
+static cairo_test_status_t
+draw (cairo_t *cr, int width, int height)
+{
+    cairo_set_source_rgb (cr, 1, 1, 1);
+    cairo_paint (cr);
+
+    /* Check if the code that guarantees start <= end hangs */
+    cairo_arc (cr, 0, 0, 1, 1024 / DBL_EPSILON * M_PI, 0);
+
+    /* Check if the code that handles huge angles hangs */
+    cairo_arc (cr, 0, 0, 1, 0, 1024 / DBL_EPSILON * M_PI);
+}
+
+CAIRO_TEST (arc_infinite_loop,
+	    "Test cairo_arc with huge angles",
+	    "arc", /* keywords */
+	    NULL, /* requirements */
+	    SIZE, SIZE,
+	    NULL, draw)