Port FuzzPathop from chromium

fuzz/FuzzPathop.cpp

+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "Fuzz.h"
+#include "SkPath.h"
+#include "SkPathOps.h"
+
+const int kLastOp = SkPathOp::kReverseDifference_SkPathOp;
+
+void BuildPath(Fuzz* fuzz,
+               SkPath* path,
+               int last_verb) {
+  uint8_t operation;
+  SkScalar a, b, c, d, e, f;
+  while (fuzz->next<uint8_t>(&operation)) {
+
+    switch (operation % (last_verb + 1)) {
+      case SkPath::Verb::kMove_Verb:
+        if (!fuzz->next<SkScalar>(&a) || !fuzz->next<SkScalar>(&b))
+          return;
+        path->moveTo(a, b);
+        break;
+
+      case SkPath::Verb::kLine_Verb:
+        if (!fuzz->next<SkScalar>(&a) || !fuzz->next<SkScalar>(&b))
+          return;
+        path->lineTo(a, b);
+        break;
+
+      case SkPath::Verb::kQuad_Verb:
+        if (!fuzz->next<SkScalar>(&a) ||
+            !fuzz->next<SkScalar>(&b) ||
+            !fuzz->next<SkScalar>(&c) ||
+            !fuzz->next<SkScalar>(&d))
+          return;
+        path->quadTo(a, b, c, d);
+        break;
+
+      case SkPath::Verb::kConic_Verb:
+        if (!fuzz->next<SkScalar>(&a) ||
+            !fuzz->next<SkScalar>(&b) ||
+            !fuzz->next<SkScalar>(&c) ||
+            !fuzz->next<SkScalar>(&d) ||
+            !fuzz->next<SkScalar>(&e))
+          return;
+        path->conicTo(a, b, c, d, e);
+        break;
+
+      case SkPath::Verb::kCubic_Verb:
+        if (!fuzz->next<SkScalar>(&a) ||
+            !fuzz->next<SkScalar>(&b) ||
+            !fuzz->next<SkScalar>(&c) ||
+            !fuzz->next<SkScalar>(&d) ||
+            !fuzz->next<SkScalar>(&e) ||
+            !fuzz->next<SkScalar>(&f))
+          return;
+        path->cubicTo(a, b, c, d, e, f);
+        break;
+
+      case SkPath::Verb::kClose_Verb:
+        path->close();
+        break;
+
+      case SkPath::Verb::kDone_Verb:
+        // In this case, simply exit.
+        return;
+    }
+  }
+}
+
+DEF_FUZZ(Pathop, fuzz) {
+    SkOpBuilder builder;
+    while (fuzz->remaining() >= sizeof(uint8_t)) {
+        SkPath path;
+        uint8_t op = fuzz->nextB();
+
+        BuildPath(fuzz, &path, SkPath::Verb::kDone_Verb);
+        builder.add(path, static_cast<SkPathOp>(op % (kLastOp + 1)));
+    }
+
+    SkPath result;
+    builder.resolve(&result);
+}