projects / ceph.git / blame
| Commit | Line | Data |
|---|---|---|
| 7c673cae FG |
1 | .. Sequences/Views//zip_view |
| 2 | ||
| 3 | zip_view | |
| 4 | ======== | |
| 5 | ||
| 6 | Synopsis | |
| 7 | -------- | |
| 8 | ||
| 9 | .. parsed-literal:: | |
| 10 | ||
| 11 | template< | |
| 12 | typename Sequences | |
| 13 | > | |
| 14 | struct zip_view | |
| 15 | { | |
| 16 | // |unspecified| | |
| 17 | // |...| | |
| 18 | }; | |
| 19 | ||
| 20 | ||
| 21 | ||
| 22 | Description | |
| 23 | ----------- | |
| 24 | ||
| 25 | Provides a "zipped" view onto several sequences; that is, represents several | |
| 26 | sequences as a single sequence of elements each of which, in turn, | |
| 27 | is a sequence of the corresponding ``Sequences``\ ' elements. | |
| 28 | ||
| 29 | ||
| 30 | Header | |
| 31 | ------ | |
| 32 | ||
| 33 | .. parsed-literal:: | |
| 34 | ||
| 35 | #include <boost/mpl/zip_view.hpp> | |
| 36 | ||
| 37 | ||
| 38 | ||
| 39 | Model of | |
| 40 | -------- | |
| 41 | ||
| 42 | * |Forward Sequence| | |
| 43 | ||
| 44 | ||
| 45 | Parameters | |
| 46 | ---------- | |
| 47 | ||
| 48 | +---------------+-----------------------------------+-------------------------------+ | |
| 49 | | Parameter | Requirement | Description | | |
| 50 | +===============+===================================+===============================+ | |
| 51 | | ``Sequences`` | A |Forward Sequence| of | Sequences to be "zipped". | | |
| 52 | | | |Forward Sequence|\ s | | | |
| 53 | +---------------+-----------------------------------+-------------------------------+ | |
| 54 | ||
| 55 | Expression semantics | |
| 56 | -------------------- | |
| 57 | ||
| 58 | |Semantics disclaimer...| |Forward Sequence|. | |
| 59 | ||
| 60 | In the following table, ``v`` is an instance of ``zip_view``, ``seq`` a |Forward Sequence| of ``n`` | |
| 61 | |Forward Sequence|\ s. | |
| 62 | ||
| 63 | +-------------------------------+-----------------------------------------------------------+ | |
| 64 | | Expression | Semantics | | |
| 65 | +===============================+===========================================================+ | |
| 66 | | .. parsed-literal:: | A lazy |Forward Sequence| ``v`` such that for each ``i`` | | |
| 67 | | | in |begin/end<v>| and for each ``j`` in | | |
| 68 | | zip_view<seq> | [``begin<seq>::type``, ``end<seq>::type``) | | |
| 69 | | zip_view<seq>::type | ``deref<i>::type`` is identical to | | |
| 70 | | | ``transform< deref<j>::type, deref<_1> >::type``. | | |
| 71 | +-------------------------------+-----------------------------------------------------------+ | |
| 72 | | ``size<v>::type`` | The size of ``v``; ``size<v>::value`` is equal to | | |
| 73 | | | :: | | |
| 74 | | | | | |
| 75 | | | deref< min_element< | | |
| 76 | | | transform_view< seq, size<_1> > | | |
| 77 | | | >::type >::type::value; | | |
| 78 | | | | | |
| 79 | | | linear complexity; see |Forward Sequence|. | | |
| 80 | +-------------------------------+-----------------------------------------------------------+ | |
| 81 | ||
| 82 | ||
| 83 | Example | |
| 84 | ------- | |
| 85 | ||
| 86 | Element-wise sum of three vectors. | |
| 87 | ||
| 88 | .. parsed-literal:: | |
| 89 | ||
| 90 | typedef vector_c<int,1,2,3,4,5> v1; | |
| 91 | typedef vector_c<int,5,4,3,2,1> v2; | |
| 92 | typedef vector_c<int,1,1,1,1,1> v3; | |
| 93 | ||
| 94 | typedef transform_view< | |
| 95 | zip_view< vector<v1,v2,v3> > | |
| 96 | , unpack_args< plus<_1,_2,_3> > | |
| 97 | > sum; | |
| 98 | ||
| 99 | BOOST_MPL_ASSERT(( equal< sum, vector_c<int,7,7,7,7,7> > )); | |
| 100 | ||
| 101 | ||
| 102 | See also | |
| 103 | -------- | |
| 104 | ||
| 105 | |Sequences|, |Views|, |filter_view|, |transform_view|, |joint_view|, |single_view|, |iterator_range| | |
| 106 | ||
| 107 | ||
| 108 |