Implement iterators for static flatbuffers Vector
This is largely a quality-of-life improvement.
Change-Id: I7fb156b90c5e71dbf8ae189117866422701590ba
Signed-off-by: James Kuszmaul <james.kuszmaul@bluerivertech.com>
diff --git a/aos/flatbuffers/static_flatbuffers_test.cc b/aos/flatbuffers/static_flatbuffers_test.cc
index acea168..2acc3c8 100644
--- a/aos/flatbuffers/static_flatbuffers_test.cc
+++ b/aos/flatbuffers/static_flatbuffers_test.cc
@@ -913,6 +913,78 @@
*object->AsFlatbuffer().unspecified_length_vector()) {
EXPECT_EQ(expected++, value);
}
+ expected = 0;
+ for (const uint8_t value : *object->unspecified_length_vector()) {
+ EXPECT_EQ(expected++, value);
+ }
TestMemory(builder.buffer());
}
+
+// Tests that the iterators on the Vector type work.
+TEST_F(StaticFlatbuffersTest, IteratorTest) {
+ Builder<TestTableStatic> builder(std::make_unique<VectorAllocator>());
+ {
+ auto vector = builder->add_unspecified_length_vector();
+ ASSERT_TRUE(vector->reserve(9000));
+ vector->resize(256);
+ uint8_t set_value = 0;
+ for (uint8_t &destination : *vector) {
+ destination = set_value;
+ ++set_value;
+ }
+ uint8_t expected = 0;
+ for (const uint8_t value : *builder->unspecified_length_vector()) {
+ EXPECT_EQ(expected, value);
+ ++expected;
+ }
+ // Exercise some of the random access iterator functionality to ensure that
+ // we have it implemented.
+ auto begin_it = vector->begin();
+ EXPECT_EQ(begin_it + 256, vector->end());
+ EXPECT_EQ(7, *(begin_it + 7));
+ EXPECT_EQ(255, *(vector->end() - 1));
+ EXPECT_EQ(256, vector->end() - vector->begin());
+ EXPECT_EQ(-256, vector->begin() - vector->end());
+ static_assert(std::random_access_iterator<decltype(vector->begin())>,
+ "The vector iterator does not meet the requirements of a "
+ "random access iterator.");
+ }
+ {
+ auto vector = builder->add_vector_of_structs();
+ vector->resize(3);
+ double set_value = 0;
+ for (SubStruct &destination : *vector) {
+ destination.mutate_x(set_value);
+ destination.mutate_y(-set_value);
+ set_value += 1.0;
+ }
+ double expected = 0;
+ for (const SubStruct &value : *builder->vector_of_structs()) {
+ EXPECT_EQ(expected, value.x());
+ EXPECT_EQ(-expected, value.y());
+ expected += 1.0;
+ }
+ static_assert(std::random_access_iterator<decltype(vector->begin())>,
+ "The vector iterator does not meet the requirements of a "
+ "random access iterator.");
+ }
+ {
+ auto vector = builder->add_vector_of_tables();
+ vector->resize(3);
+ int set_value = 0;
+ for (SubTableStatic &destination : *vector) {
+ destination.set_foo(set_value);
+ set_value += 1;
+ }
+ int expected = 0;
+ for (const SubTableStatic &value : *builder->vector_of_tables()) {
+ EXPECT_EQ(expected, value.foo());
+ EXPECT_FALSE(value.has_baz());
+ expected += 1;
+ }
+ static_assert(std::random_access_iterator<decltype(vector->begin())>,
+ "The vector iterator does not meet the requirements of a "
+ "random access iterator.");
+ }
+}
} // namespace aos::fbs::testing
diff --git a/aos/flatbuffers/static_vector.h b/aos/flatbuffers/static_vector.h
index f4cfea6..0aff48e 100644
--- a/aos/flatbuffers/static_vector.h
+++ b/aos/flatbuffers/static_vector.h
@@ -109,7 +109,87 @@
template <typename T, size_t kStaticLength, bool kInline,
size_t kForceAlign = 0, bool kNullTerminate = false>
class Vector : public ResizeableObject {
+ template <typename VectorType, typename ValueType>
+ class generic_iterator {
+ public:
+ using iterator_category = std::random_access_iterator_tag;
+ using value_type = ValueType;
+ using difference_type = std::ptrdiff_t;
+ using pointer = value_type *;
+ using reference = value_type &;
+
+ explicit generic_iterator(VectorType *vector, size_t index)
+ : vector_(vector), index_(index) {}
+ generic_iterator(const generic_iterator &) = default;
+ generic_iterator() : vector_(nullptr), index_(0) {}
+ generic_iterator &operator=(const generic_iterator &) = default;
+
+ generic_iterator &operator++() {
+ ++index_;
+ return *this;
+ }
+ generic_iterator operator++(int) {
+ generic_iterator retval = *this;
+ ++(*this);
+ return retval;
+ }
+ generic_iterator &operator--() {
+ --index_;
+ return *this;
+ }
+ generic_iterator operator--(int) {
+ generic_iterator retval = *this;
+ --(*this);
+ return retval;
+ }
+ bool operator==(const generic_iterator &other) const {
+ CHECK_EQ(other.vector_, vector_);
+ return index_ == other.index_;
+ }
+ std::strong_ordering operator<=>(const generic_iterator &other) const {
+ CHECK_EQ(other.vector_, vector_);
+ return index_ <=> other.index_;
+ }
+ reference operator*() const { return vector_->at(index_); }
+ difference_type operator-(const generic_iterator &other) const {
+ CHECK_EQ(other.vector_, vector_);
+ return index_ - other.index_;
+ }
+ generic_iterator operator-(difference_type decrement) const {
+ return generic_iterator(vector_, index_ - decrement);
+ }
+ friend generic_iterator operator-(difference_type decrement,
+ const generic_iterator &rhs) {
+ return rhs - decrement;
+ }
+ generic_iterator operator+(difference_type increment) const {
+ return generic_iterator(vector_, index_ + increment);
+ }
+ friend generic_iterator operator+(difference_type increment,
+ const generic_iterator &rhs) {
+ return rhs + increment;
+ }
+ generic_iterator &operator+=(difference_type increment) {
+ index_ += increment;
+ return *this;
+ }
+ generic_iterator &operator-=(difference_type increment) {
+ index_ -= increment;
+ return *this;
+ }
+ reference operator[](difference_type index) const {
+ return *(*this + index);
+ }
+
+ private:
+ VectorType *vector_;
+ size_t index_;
+ };
+
public:
+ using iterator = generic_iterator<Vector, T>;
+ using const_iterator = generic_iterator<const Vector, const T>;
+
static_assert(kInline || !kNullTerminate,
"It does not make sense to null-terminate vectors of objects.");
// Type stored inline in the serialized vector (offsets for tables/strings; T
@@ -380,6 +460,12 @@
return inline_data();
}
+ // Iterators to allow easy use with standard C++ features.
+ iterator begin() { return iterator(this, 0); }
+ iterator end() { return iterator(this, size()); }
+ const_iterator begin() const { return const_iterator(this, 0); }
+ const_iterator end() const { return const_iterator(this, size()); }
+
std::string SerializationDebugString() const {
std::stringstream str;
str << "Raw Size: " << kSize << " alignment: " << kAlign