Demo fuzz for Herb

fuzz/FuzzScaleToSides.cpp

Index: fuzz/FuzzScaleToSides.cpp
diff --git a/fuzz/FuzzScaleToSides.cpp b/fuzz/FuzzScaleToSides.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..88a2b920b0cd483d91bc0caa96dd7db9cfe0edcf
--- /dev/null
+++ b/fuzz/FuzzScaleToSides.cpp
@@ -0,0 +1,45 @@
+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+// Reminder of how to run:
+//  $ env CC=afl-clang CXX=afl-clang++ ./gyp_skia
+//  $ ninja -C out/Debug fuzz
+//  $ afl-fuzz -i fuzz-in -o fuzz-out out/Debug/fuzz -n ScaleToSides -b @@
+// where you seed fuzz-in/ with one or more small files.
+
+#include "Fuzz.h"
+#include "SkScaleToSides.h"
+#include <cmath>
+
+DEF_FUZZ(ScaleToSides, fuzz) {
+    float radius1 = fuzz->nextF(),
+          radius2 = fuzz->nextF(),
+          width   = fuzz->nextF();
+    SkDebugf("%g %g %g\n", radius1, radius2, width);
+
+    if (!std::isfinite(radius1) ||

[kjlubick, 2016/01/21 17:17:52]

Why not std::isnormal(), which accounts for infinite, NaN and zero?

[mtklein, 2016/01/21 17:37:46]

Zeros and subnormals should work for some of these.

[herb_g, 2016/01/21 17:38:20]

What he said.

+        !std::isfinite(radius2) ||
+        !std::isfinite(width))
+    {
+        fuzz->signalBoring();
+    }
+
+    if (width <= 0.0f) {
+        fuzz->signalBoring();
+    }
+
+    double scale = (double)width / ((double)radius1 + (double)radius2);
+    if (scale >= 1.0) {
+        fuzz->signalBoring();
+    }
+    ScaleToSides::AdjustRadii(width, scale, &radius1, &radius2);
+
+    // TODO(mtklein): add fuzz->keepResult()
+    volatile float junk = 0.0f;
+    junk *= radius1;
+    junk *= radius2;
+}