| ////////////////////////////////////////////////////////////////////////////// |
| // |
| // (C) Copyright Ion Gaztanaga 2015-2015. Distributed under the Boost |
| // Software License, Version 1.0. (See accompanying file |
| // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) |
| // |
| // See http://www.boost.org/libs/container for documentation. |
| // |
| ////////////////////////////////////////////////////////////////////////////// |
| //[doc_pmr_ShoppingList_hpp |
| //ShoppingList.hpp |
| #include <boost/container/pmr/vector.hpp> |
| #include <boost/container/pmr/string.hpp> |
| |
| class ShoppingList |
| { |
| // A vector of strings using polymorphic allocators. Every element |
| // of the vector will use the same allocator as the vector itself. |
| boost::container::pmr::vector_of |
| <boost::container::pmr::string>::type m_strvec; |
| //Alternatively in compilers that support template aliases: |
| // boost::container::pmr::vector<boost::container::pmr::string> m_strvec; |
| public: |
| |
| // This makes uses_allocator<ShoppingList, memory_resource*>::value true |
| typedef boost::container::pmr::memory_resource* allocator_type; |
| |
| // If the allocator is not specified, "m_strvec" uses pmr::get_default_resource(). |
| explicit ShoppingList(allocator_type alloc = 0) |
| : m_strvec(alloc) {} |
| |
| // Copy constructor. As allocator is not specified, |
| // "m_strvec" uses pmr::get_default_resource(). |
| ShoppingList(const ShoppingList& other) |
| : m_strvec(other.m_strvec) {} |
| |
| // Copy construct using the given memory_resource. |
| ShoppingList(const ShoppingList& other, allocator_type a) |
| : m_strvec(other.m_strvec, a) {} |
| |
| allocator_type get_allocator() const |
| { return m_strvec.get_allocator().resource(); } |
| |
| void add_item(const char *item) |
| { m_strvec.emplace_back(item); } |
| |
| //... |
| }; |
| |
| //]] |
| |
| //[doc_pmr_main_cpp |
| |
| //=#include "ShoppingList.hpp" |
| #include <cassert> |
| #include <boost/container/pmr/list.hpp> |
| #include <boost/container/pmr/monotonic_buffer_resource.hpp> |
| |
| void processShoppingList(const ShoppingList&) |
| { /**/ } |
| |
| int main() |
| { |
| using namespace boost::container; |
| //All memory needed by folder and its contained objects will |
| //be allocated from the default memory resource (usually new/delete) |
| pmr::list_of<ShoppingList>::type folder; // Default allocator resource |
| //Alternatively in compilers that support template aliases: |
| // boost::container::pmr::list<ShoppingList> folder; |
| { |
| char buffer[1024]; |
| pmr::monotonic_buffer_resource buf_rsrc(&buffer, 1024); |
| |
| //All memory needed by temporaryShoppingList will be allocated |
| //from the local buffer (speeds up "processShoppingList") |
| ShoppingList temporaryShoppingList(&buf_rsrc); |
| assert(&buf_rsrc == temporaryShoppingList.get_allocator()); |
| |
| //list nodes, and strings "salt" and "pepper" will be allocated |
| //in the stack thanks to "monotonic_buffer_resource". |
| temporaryShoppingList.add_item("salt"); |
| temporaryShoppingList.add_item("pepper"); |
| //... |
| |
| //All modifications and additions to "temporaryShoppingList" |
| //will use memory from "buffer" until it's exhausted. |
| processShoppingList(temporaryShoppingList); |
| |
| //Processing done, now insert it in "folder", |
| //which uses the default memory resource |
| folder.push_back(temporaryShoppingList); |
| assert(pmr::get_default_resource() == folder.back().get_allocator()); |
| //temporaryShoppingList, buf_rsrc, and buffer go out of scope |
| } |
| return 0; |
| } |
| |
| //] |