Example 5: Using the UnsynchronizedBArrayMemoryResource class

Also see Example 4: Using the UnsynchronizedBufferMemoryResource class

 
#include <iostream>
 
#include <gtest/gtest.h>
 
#include "cetl/pf17/array_memory_resource.hpp"
#include "cetl/pf17/byte.hpp"
 
TEST(example_05_array_memory_resource, example_0)
{
static_assert(alignof(std::max_align_t) < 128, "Wow, what hardware are you running on?");
constexpr std::size_t                                               BufferSizeBytes = 64;
cetl::pf17::pmr::UnsynchronizedArrayMemoryResource<BufferSizeBytes> resource{};
 
// let's say we have a buffer that must be aligned to a 128-byte (1024-bit) boundary. If we tried to use
// UnsynchronizedArrayMemoryResource with a 64-byte internal array, on a typical system, the allocation would fail.
 
void* r = nullptr;
#ifdefined(__cpp_exceptions)
try
{
#endif
    r = resource.allocate(64, 128);
#ifdefined(__cpp_exceptions)
} catch (const std::bad_alloc&)
{
    // This is expected.
}
#endif
std::cout << "Over-aligned attempt failed: " << r << std::endl;

}
 
TEST(example_05_array_memory_resource, example_1)
{
// By over-provisioning the buffer you can now get the alignment you want:
constexpr std::size_t                                               BufferSizeBytes = 64 + 128;
cetl::pf17::pmr::UnsynchronizedArrayMemoryResource<BufferSizeBytes> resource{};
 
void* r = resource.allocate(64, 128);
 
std::cout << "Over-aligned address at: " << r << std::endl;
 
resource.deallocate(r, 64, 128);
}