A vector-like class to create structures of arrays.
See src/main.cpp for a detailed usage sample.
vector_base is a class template that provides a basic implementation of a vector-like container using the Structure of Arrays (SoA) data layout. The container stores its elements in separate arrays for each data member, rather than storing each element as a struct or object with all data members together.
The vector_base class provides a number of member functions for manipulating the container, such as size(), capacity(), empty(), reserve(), shrink_to_fit(), clear(), push_back(), pop_back(), and resize(). It also provides a number of iterator classes: const_iterator, iterator, partial_const_iterator, and partial_iterator.
The template parameters of vector_base are:
MembersDesc: an enum type that lists the data members of the container.
Allocator: the allocator type to use for allocating and deallocating the memory used by the container.
Types...: the types of the data members of the container.
The data members are specified by MembersDesc, which should be an enum whose values correspond to the indices of the Types... parameter pack. For example, if Types... is int, float, bool, then MembersDesc might be:
enum class MembersDesc
{
Int = 0,
Float = 1,
Bool = 2,
Count = 3
};
The value_list, reference_list, and const_reference_list typedefs are tuples of the data members, data members references, and const data member references, respectively.
The partial_ref_list and partial_const_ref_list templates are used to create partial views of the container, where only a subset of the data members are exposed. These templates take a list of member indices as template parameters and produce tuples of references to those members.
Overall, vector_base provides a flexible, low-level building block for constructing data structures using the SoA layout, allowing for efficient data access and manipulation.
// Tests the partial iterators of a vector_base
TEST(VectorBaseTest, PartialIterator)
{
using VectorBase = vector_base<MembersDesc, Allocator, int, float, double>;
VectorBase vector;
vector.push_back(1, 2.0f, 3.0);
// Test partial iteration over int and double elements
auto it = vector.begin<MembersDesc::Int, MembersDesc::Double>();
EXPECT_EQ(std::get<0>(*it), 1);
EXPECT_EQ(std::get<1>(*it), 3.0);
++it;
EXPECT_EQ(it, vector.end<MembersDesc::Int, MembersDesc::Double>());
}
Clang14 + libstdc++ (gnu): https://quick-bench.com/q/-TwdTeJ4256ZQpSB9GXL8Kw6WB0
Clang14 + libc++ (llvm): https://quick-bench.com/q/dwHoJR5MAq55UUreN26ASdEybHo