From: Søren Sandmann Pedersen <s...@redhat.com>
This program demonstrates a bug in gradient walker, where some integer
overflows cause colors outside the range [0, 255] to be generated,
which in turns cause 'invalid' floating point exceptions when those
colors are converted to uint8_t.
The bug was first reported by Owen Taylor on the #cairo IRC channel.
---
test/Makefile.sources | 1 +
test/radial-invalid.c | 54 +++++++++++++++++++++++++++++++++++++++++++++++++++
test/utils.c | 10 ++++++++++
test/utils.h | 1 +
4 files changed, 66 insertions(+)
create mode 100644 test/radial-invalid.c
diff --git a/test/Makefile.sources b/test/Makefile.sources
index 9b520ec..c7f1657 100644
--- a/test/Makefile.sources
+++ b/test/Makefile.sources
@@ -2,6 +2,7 @@
TESTPROGRAMS = \
prng-test \
a1-trap-test \
+ radial-invalid \
pdf-op-test \
region-test \
region-translate-test \
diff --git a/test/radial-invalid.c b/test/radial-invalid.c
new file mode 100644
index 0000000..ec85fe3
--- /dev/null
+++ b/test/radial-invalid.c
@@ -0,0 +1,54 @@
+#include <math.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include "utils.h"
+
+#define WIDTH 100
+#define HEIGHT 100
+
+int
+main ()
+{
+ pixman_image_t *radial;
+ pixman_image_t *dest = pixman_image_create_bits (
+ PIXMAN_a8r8g8b8, WIDTH, HEIGHT, NULL, -1);
+
+ static const pixman_transform_t xform =
+ {
+ { { 0x346f7, 0x0, 0x0 },
+ { 0x0, 0x346f7, 0x0 },
+ { 0x0, 0x0, 0x10000 }
+ },
+ };
+
+ static const pixman_gradient_stop_t stops[] =
+ {
+ { 0xde61, { 0x4481, 0x96e8, 0x1e6a, 0x29e1 } },
+ { 0xfdd5, { 0xfa10, 0xcc26, 0xbc43, 0x1eb7 } },
+ { 0xfe1e, { 0xd257, 0x5bac, 0x6fc2, 0xa33b } },
+ };
+
+ static const pixman_point_fixed_t inner = { 0x320000, 0x320000 };
+ static const pixman_point_fixed_t outer = { 0x320000, 0x3cb074 };
+
+ enable_divbyzero_exceptions ();
+ enable_invalid_exceptions ();
+
+ radial = pixman_image_create_radial_gradient (
+ &inner,
+ &outer,
+ 0xab074, /* inner radius */
+ 0x0, /* outer radius */
+ stops, sizeof (stops) / sizeof (stops[0]));
+
+ pixman_image_set_repeat (radial, PIXMAN_REPEAT_REFLECT);
+ pixman_image_set_transform (radial, &xform);
+
+ pixman_image_composite (
+ PIXMAN_OP_OVER,
+ radial, NULL, dest,
+ 0, 0, 0, 0,
+ 0, 0, WIDTH, HEIGHT);
+
+ return 0;
+}
diff --git a/test/utils.c b/test/utils.c
index 1888417..ab3424f 100644
--- a/test/utils.c
+++ b/test/utils.c
@@ -849,6 +849,16 @@ enable_divbyzero_exceptions (void)
#endif
}
+void
+enable_invalid_exceptions (void)
+{
+#ifdef HAVE_FENV_H
+#ifdef HAVE_FEENABLEEXCEPT
+ feenableexcept (FE_INVALID);
+#endif
+#endif
+}
+
void *
aligned_malloc (size_t align, size_t size)
{
diff --git a/test/utils.h b/test/utils.h
index ebb14d9..6804334 100644
--- a/test/utils.h
+++ b/test/utils.h
@@ -120,6 +120,7 @@ fail_after (int seconds, const char *msg);
/* If possible, enable traps for floating point exceptions */
void enable_divbyzero_exceptions(void);
+void enable_invalid_exceptions(void);
/* Converts a8r8g8b8 pixels to pixels that
* - are not premultiplied,
--
1.8.3.1
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