Made sure tests.cpp is testing the new vector iterator functionality.

Also fixes a potential big-endian bug, and makes iterators work
correctly with pointer types.

Change-Id: Ib7f88fe9e6053d1a9afa7895fba0695627c158b1
Tested: on Windows and Linux

include/flatbuffers/flatbuffers.h

@@ -20,6 +20,7 @@
 #include <assert.h>
 
 #include <cstdint>
+#include <cstddef>
 #include <cstring>
 #include <string>
 #include <type_traits>
@@ -163,15 +164,14 @@ template<typename T> struct IndirectHelper<Offset<T>> {
   static const size_t element_stride = sizeof(uoffset_t);
   static return_type Read(const uint8_t *p, uoffset_t i) {
     p += i * sizeof(uoffset_t);
-    return EndianScalar(reinterpret_cast<return_type>(
-        p + ReadScalar<uoffset_t>(p)));
+    return reinterpret_cast<return_type>(p + ReadScalar<uoffset_t>(p));
   }
 };
 template<typename T> struct IndirectHelper<const T *> {
-  typedef const T &return_type;
+  typedef const T *return_type;
   static const size_t element_stride = sizeof(T);
   static return_type Read(const uint8_t *p, uoffset_t i) {
-    return *reinterpret_cast<const T *>(p + i * sizeof(T));
+    return reinterpret_cast<const T *>(p + i * sizeof(T));
   }
 };
 
@@ -213,12 +213,16 @@ public:
     return data_ != other.data_;
   }
 
+  ptrdiff_t operator-(const VectorIterator& other) const {
+    return (data_ - other.data_) / IndirectHelper<T>::element_stride;
+  }
+
   typename super_type::value_type operator *() const {
     return IndirectHelper<T>::Read(data_, 0);
   }
 
-  typename super_type::pointer operator->() const {
-    return &IndirectHelper<T>::Read(data_, 0);
+  typename super_type::value_type operator->() const {
+    return IndirectHelper<T>::Read(data_, 0);
   }
 
   VectorIterator &operator++() {

tests/test.cpp

@@ -135,8 +135,8 @@ void AccessFlatBufferTest(const std::string &flatbuf) {
   auto inventory = monster->inventory();
   TEST_NOTNULL(inventory);
   unsigned char inv_data[] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };
-  for (flatbuffers::uoffset_t i = 0; i < inventory->Length(); i++)
-    TEST_EQ(inventory->Get(i), inv_data[i]);
+  for (auto it = inventory->begin(); it != inventory->end(); ++it)
+    TEST_EQ(*it, inv_data[it - inventory->begin()]);
 
   // Example of accessing a union:
   TEST_EQ(monster->test_type(), Any_Monster);  // First make sure which it is.
@@ -153,7 +153,8 @@ void AccessFlatBufferTest(const std::string &flatbuf) {
   // Example of accessing a vector of tables:
   auto vecoftables = monster->testarrayoftables();
   TEST_EQ(vecoftables->Length(), 1U);
-  TEST_EQ(vecoftables->Get(0)->hp(), 20);
+  for (auto it = vecoftables->begin(); it != vecoftables->end(); ++it)
+    TEST_EQ(it->hp(), 20);
 
   // Since Flatbuffers uses explicit mechanisms to override the default
   // compiler alignment, double check that the compiler indeed obeys them:
@@ -163,12 +164,16 @@ void AccessFlatBufferTest(const std::string &flatbuf) {
 
   auto tests = monster->test4();
   TEST_NOTNULL(tests);
-  auto &test_0 = tests->Get(0);
-  auto &test_1 = tests->Get(1);
-  TEST_EQ(test_0.a(), 10);
-  TEST_EQ(test_0.b(), 20);
-  TEST_EQ(test_1.a(), 30);
-  TEST_EQ(test_1.b(), 40);
+  auto test_0 = tests->Get(0);
+  auto test_1 = tests->Get(1);
+  TEST_EQ(test_0->a(), 10);
+  TEST_EQ(test_0->b(), 20);
+  TEST_EQ(test_1->a(), 30);
+  TEST_EQ(test_1->b(), 40);
+  for (auto it = tests->begin(); it != tests->end(); ++it) {
+    TEST_EQ(it->a() == 10 || it->a() == 30, true);  // Just testing iterators.
+  }
+
 }
 
 // example of parsing text straight into a buffer, and generating