{"id":1293,"date":"2013-07-30T14:47:00","date_gmt":"2013-07-30T14:47:00","guid":{"rendered":"https:\/\/blogs.msdn.microsoft.com\/vcblog\/2013\/07\/30\/new-features-in-ccxs-collection-h-for-vs-2013-rtm\/"},"modified":"2019-02-18T18:40:58","modified_gmt":"2019-02-18T18:40:58","slug":"new-features-in-ccxs-collection-h-for-vs-2013-rtm","status":"publish","type":"post","link":"https:\/\/devblogs.microsoft.com\/cppblog\/new-features-in-ccxs-collection-h-for-vs-2013-rtm\/","title":{"rendered":"New Features in C++\/CX's <collection.h> for VS 2013 RTM"},"content":{"rendered":"
\n

Introduction:<\/h2>\n

Hi, I’m Brandon Jacobs, an intern on the Visual C++ Libraries team. For part of my internship, I was tasked with adding new features to Stephan T. Lavavej’s <collection.h><\/a>. It was certainly an honor to be one of the few to contribute to <collection.h>. You can find these changes in VS 2013 RTM (these changes are not in 2013 Preview).<\/p>\n

 <\/p>\n

\n

Summary:<\/h2>\n<\/div>\n

These are the changes I’ve made to <collection.h>:<\/p>\n

1.            Added UnorderedMap and UnorderedMapView wrapper classes to <collection.h>.<\/p>\n

2.            Added initializer_list constructors to Vector, VectorView, Map, MapView,  UnorderedMap, and UnorderedMapView.<\/p>\n

3.            Added validation so that customers use valid WinRT types to instantiate the collections in <collection.h>.<\/p>\n

 <\/p>\n

\n

Features:<\/h2>\n<\/div>\n

UnorderedMap and UnorderedMapView:<\/p>\n

This is the wrapper class for the std::unordered_map class. The functionality is the same as Map and MapView. The only difference is the underlying data structure, which is a hash table instead of a balanced binary tree. So, types must be hashable and must be able to show equality. Just like Map and MapView defaults to std::less,  UnorderedMap and UnorderedMapView defaults to std::hash and std::equal_to. Both the hash and equality predicates are template parameters, so you are allowed to change the actions of UnorderedMap and UnorderedMapView by providing your own predicates.<\/p>\n

 <\/p>\n

initializer_list constructors:<\/p>\n

You can now construct any data structure using the C++11 initializer_list constructors.<\/p>\n

An example:<\/p>\n

namespace WFC = Windows::Foundation::Collections;<\/span><\/p>\n

namespace PC = Platform::Collections;<\/span><\/p>\n

WFC::IVector<int>^ v = ref new PC::Vector<int>{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };<\/span><\/p>\n

WFC::IMap<int, int>^ m<\/span><\/p>\n

= ref new PC::Map<int, int>{ { 1, 10 }, { 2, 20 }, { 3, 30 }, { 4, 40 } };<\/span><\/p>\n

WFC::IMap<int, int>^ m2<\/span><\/p>\n

= ref new PC::UnorderedMap<int, int>{ { 1, 10 }, { 2, 20 }, { 3, 30 }, { 4, 40 } };<\/span><\/p>\n

 <\/p>\n

Valid WinRT types only:<\/p>\n

We now check whether the type you want to store in your given data structure is a valid WinRT type. Currently if you have:<\/p>\n

PC::Vector<ordinary_cpp_class><\/span><\/p>\n

You will get an odd compiler error. Now we check whether the types passed in are valid WinRT types. If this check fails, you will now get a much nicer compiler error that even includes the line in which you tried to create a collection with an invalid type.<\/p>\n

Only the items that will appear in the Windows::Foundation::Collections interfaces need to be valid WinRT types. Predicates such as std::less, std::hash, etc. are not passed into the Windows::Foundation::Collections interfaces, so they are not affected by that restriction.<\/p>\n

Valid WinRT types are:<\/p>\n

    \n
  1. integers<\/li>\n
  2. interface class ^<\/li>\n
  3. public ref class^<\/li>\n
  4. value struct<\/li>\n
  5. public enum class<\/li>\n<\/ol>\n

     <\/p>\n

    Thank you for taking the time and reading this post,<\/p>\n

    Brandon Jacobs<\/p>\n

    SDE Intern – Visual C++ Libraries<\/p>\n<\/div>\n","protected":false},"excerpt":{"rendered":"

    Introduction: Hi, I’m Brandon Jacobs, an intern on the Visual C++ Libraries team. For part of my internship, I was tasked with adding new features to Stephan T. Lavavej’s <collection.h>. It was certainly an honor to be one of the few to contribute to <collection.h>. You can find these changes in VS 2013 RTM (these […]<\/p>\n","protected":false},"author":273,"featured_media":35994,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[1],"tags":[121,201],"class_list":["post-1293","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-cplusplus","tag-ccx","tag-collection-h"],"acf":[],"blog_post_summary":"

    Introduction: Hi, I’m Brandon Jacobs, an intern on the Visual C++ Libraries team. For part of my internship, I was tasked with adding new features to Stephan T. Lavavej’s <collection.h>. It was certainly an honor to be one of the few to contribute to <collection.h>. You can find these changes in VS 2013 RTM (these […]<\/p>\n","_links":{"self":[{"href":"https:\/\/devblogs.microsoft.com\/cppblog\/wp-json\/wp\/v2\/posts\/1293","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/devblogs.microsoft.com\/cppblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/devblogs.microsoft.com\/cppblog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/cppblog\/wp-json\/wp\/v2\/users\/273"}],"replies":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/cppblog\/wp-json\/wp\/v2\/comments?post=1293"}],"version-history":[{"count":0,"href":"https:\/\/devblogs.microsoft.com\/cppblog\/wp-json\/wp\/v2\/posts\/1293\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/cppblog\/wp-json\/wp\/v2\/media\/35994"}],"wp:attachment":[{"href":"https:\/\/devblogs.microsoft.com\/cppblog\/wp-json\/wp\/v2\/media?parent=1293"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/cppblog\/wp-json\/wp\/v2\/categories?post=1293"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/cppblog\/wp-json\/wp\/v2\/tags?post=1293"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}