1 | ////////////////////////////////////////////////////////////////////////////// |
2 | // |
3 | // (C) Copyright Ion Gaztanaga 2015-2015. Distributed under the Boost |
4 | // Software License, Version 1.0. (See accompanying file |
5 | // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) |
6 | // |
7 | // See http://www.boost.org/libs/container for documentation. |
8 | // |
9 | ////////////////////////////////////////////////////////////////////////////// |
10 | //[doc_pmr_ShoppingList_hpp |
11 | //ShoppingList.hpp |
12 | #include <boost/container/pmr/vector.hpp> |
13 | #include <boost/container/pmr/string.hpp> |
14 | |
15 | class ShoppingList |
16 | { |
17 | // A vector of strings using polymorphic allocators. Every element |
18 | // of the vector will use the same allocator as the vector itself. |
19 | boost::container::pmr::vector_of |
20 | <boost::container::pmr::string>::type m_strvec; |
21 | //Alternatively in compilers that support template aliases: |
22 | // boost::container::pmr::vector<boost::container::pmr::string> m_strvec; |
23 | public: |
24 | |
25 | // This makes uses_allocator<ShoppingList, memory_resource*>::value true |
26 | typedef boost::container::pmr::memory_resource* allocator_type; |
27 | |
28 | // If the allocator is not specified, "m_strvec" uses pmr::get_default_resource(). |
29 | explicit ShoppingList(allocator_type alloc = 0) |
30 | : m_strvec(alloc) {} |
31 | |
32 | // Copy constructor. As allocator is not specified, |
33 | // "m_strvec" uses pmr::get_default_resource(). |
34 | ShoppingList(const ShoppingList& other) |
35 | : m_strvec(other.m_strvec) {} |
36 | |
37 | // Copy construct using the given memory_resource. |
38 | ShoppingList(const ShoppingList& other, allocator_type a) |
39 | : m_strvec(other.m_strvec, a) {} |
40 | |
41 | allocator_type get_allocator() const |
42 | { return m_strvec.get_allocator().resource(); } |
43 | |
44 | void add_item(const char *item) |
45 | { m_strvec.emplace_back(args&: item); } |
46 | |
47 | //... |
48 | }; |
49 | |
50 | //]] |
51 | |
52 | //[doc_pmr_main_cpp |
53 | |
54 | //=#include "ShoppingList.hpp" |
55 | #include <cassert> |
56 | #include <boost/container/pmr/list.hpp> |
57 | #include <boost/container/pmr/monotonic_buffer_resource.hpp> |
58 | |
59 | void processShoppingList(const ShoppingList&) |
60 | { /**/ } |
61 | |
62 | int main() |
63 | { |
64 | using namespace boost::container; |
65 | //All memory needed by folder and its contained objects will |
66 | //be allocated from the default memory resource (usually new/delete) |
67 | pmr::list_of<ShoppingList>::type folder; // Default allocator resource |
68 | //Alternatively in compilers that support template aliases: |
69 | // boost::container::pmr::list<ShoppingList> folder; |
70 | { |
71 | char buffer[1024]; |
72 | pmr::monotonic_buffer_resource buf_rsrc(&buffer, 1024); |
73 | |
74 | //All memory needed by temporaryShoppingList will be allocated |
75 | //from the local buffer (speeds up "processShoppingList") |
76 | ShoppingList temporaryShoppingList(&buf_rsrc); |
77 | assert(&buf_rsrc == temporaryShoppingList.get_allocator()); |
78 | |
79 | //list nodes, and strings "salt" and "pepper" will be allocated |
80 | //in the stack thanks to "monotonic_buffer_resource". |
81 | temporaryShoppingList.add_item(item: "salt" ); |
82 | temporaryShoppingList.add_item(item: "pepper" ); |
83 | //... |
84 | |
85 | //All modifications and additions to "temporaryShoppingList" |
86 | //will use memory from "buffer" until it's exhausted. |
87 | processShoppingList(temporaryShoppingList); |
88 | |
89 | //Processing done, now insert it in "folder", |
90 | //which uses the default memory resource |
91 | folder.push_back(x: temporaryShoppingList); |
92 | assert(pmr::get_default_resource() == folder.back().get_allocator()); |
93 | //temporaryShoppingList, buf_rsrc, and buffer go out of scope |
94 | } |
95 | return 0; |
96 | } |
97 | |
98 | //] |
99 | |