Example 6: Using the MemoryResourceDeleter class

Full example for cetl::pmr::MemoryResourceDeleter

 
#include "cetl/pf17/cetlpf.hpp"
#include "cetl/pmr/memory.hpp"
 
#include <vector>
#include <algorithm>
#include <iostream>
 
#include <gtest/gtest.h>
 
TEST(example_06_memory_resource_deleter, example_usage)
{
// Let's say you wanted to store a bunch of buffers in a heap so you can get the largest one quickly.
// You could do something like this:
 
using MemoryResourcePointer = std::unique_ptr<void, cetl::pmr::MemoryResourceDeleter<cetl::pmr::memory_resource>>;
 
struct ByteBuffer
{
    MemoryResourcePointer data;
    std::size_t           size;
};
 
cetl::pmr::memory_resource* resource = cetl::pmr::new_delete_resource();
auto                        buffer_0 = ByteBuffer{{resource->allocate(256), {resource, 256}}, 256};
auto                        buffer_1 = ByteBuffer{{resource->allocate(512), {resource, 512}}, 512};
auto                        buffer_2 = ByteBuffer{{resource->allocate(1024), {resource, 1024}}, 1024};
std::vector<ByteBuffer>     buffers;
buffers.push_back(std::move(buffer_0));
buffers.push_back(std::move(buffer_1));
buffers.push_back(std::move(buffer_2));
 
std::make_heap(buffers.begin(), buffers.end(), [](const auto& lhs, const auto& rhs) {
    return lhs.size < rhs.size;
});
 
auto& largest_buffer = buffers.front();
 
std::cout << "Largest buffer size: " << largest_buffer.size << std::endl;
 
// Now as long as the vector "buffers" is in scope, the buffers will be valid. When the vector is destroyed,
// the buffers will be freed using the correct memory resource.

}