Port FuzzPathop from chromium

fuzz/Fuzz.h

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef Fuzz_DEFINED
 #define Fuzz_DEFINED
 
 #include "SkData.h"
 #include "SkTRegistry.h"
 #include "SkTypes.h"
 
 class Fuzz : SkNoncopyable {
 public:
     explicit Fuzz(SkData*);
 
+    // Returns the total number of "random" bytes available.
+    size_t size();
+    // Returns the total number of "random" bytes remaining for randomness.
+    size_t remaining();
+
+    template <typename T>
+    bool next(T* n);
+
     bool nextBool();
     uint8_t  nextB();
     uint32_t nextU();
     // This can be nan, +- infinity, 0, anything.
     float    nextF();
     // Returns a float between [0..1) as a IEEE float
     float    nextF1();
 
     // Return the next fuzzed value [min, max) as an unsigned 32bit integer.
     uint32_t nextRangeU(uint32_t min, uint32_t max);
     /**
      *  Returns next fuzzed value [min...max) as a float.
      *  Will not be Infinity or NaN.
      */
     float    nextRangeF(float    min, float    max);
 
     void signalBug   ();  // Tell afl-fuzz these inputs found a bug.
     void signalBoring();  // Tell afl-fuzz these inputs are not worth testing.
 
 private:
     template <typename T>
     T nextT();
 
     SkAutoTUnref<SkData> fBytes;
     int fNextByte;
 };
 
+template <typename T>
+bool Fuzz::next(T* n) {
+    if (fNextByte + sizeof(T) > fBytes->size()) {
+        return false;
+    }
+
+    memcpy(n, fBytes->bytes() + fNextByte, sizeof(T));
+    fNextByte += sizeof(T);
+    return true;
+}
+
 struct Fuzzable {
     const char* name;
     void (*fn)(Fuzz*);
 };
 
 #define DEF_FUZZ(name, f)                                        \
     static void fuzz_##name(Fuzz*);                              \
     SkTRegistry<Fuzzable> register_##name({#name, fuzz_##name}); \
     static void fuzz_##name(Fuzz* f)
 
 #endif//Fuzz_DEFINED