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