projects / ceph.git / blame
| Commit | Line | Data |
|---|---|---|
| 7c673cae FG |
1 | .. Algorithms/Transformation Algorithms//transform |30 |
| 2 | ||
| 3 | transform | |
| 4 | ========= | |
| 5 | ||
| 6 | Synopsis | |
| 7 | -------- | |
| 8 | ||
| 9 | .. parsed-literal:: | |
| 10 | ||
| 11 | template< | |
| 12 | typename Sequence | |
| 13 | , typename Op | |
| 14 | , typename In = |unspecified| | |
| 15 | > | |
| 16 | struct transform | |
| 17 | { | |
| 18 | typedef |unspecified| type; | |
| 19 | }; | |
| 20 | ||
| 21 | template< | |
| 22 | typename Seq1 | |
| 23 | , typename Seq2 | |
| 24 | , typename BinaryOp | |
| 25 | , typename In = |unspecified| | |
| 26 | > | |
| 27 | struct transform | |
| 28 | { | |
| 29 | typedef |unspecified| type; | |
| 30 | }; | |
| 31 | ||
| 32 | ||
| 33 | Description | |
| 34 | ----------- | |
| 35 | ||
| 36 | ``transform`` is an |overloaded name|: | |
| 37 | ||
| 38 | * ``transform<Sequence,Op>`` returns a transformed copy of the original sequence | |
| 39 | produced by applying an unary transformation ``Op`` to every element | |
| 40 | in the |begin/end<Sequence>| range. | |
| 41 | ||
| 42 | * ``transform<Seq1,Seq2,BinaryOp>`` returns a new sequence produced by applying a | |
| 43 | binary transformation ``BinaryOp`` to a pair of elements (e\ :sub:`1`, e2\ :sub:`1`) | |
| 44 | from the corresponding |begin/end<Seq1>| and |begin/end<Seq2>| ranges. | |
| 45 | ||
| 46 | |transformation algorithm disclaimer| | |
| 47 | ||
| 48 | ||
| 49 | Header | |
| 50 | ------ | |
| 51 | ||
| 52 | .. parsed-literal:: | |
| 53 | ||
| 54 | #include <boost/mpl/transform.hpp> | |
| 55 | ||
| 56 | ||
| 57 | Model of | |
| 58 | -------- | |
| 59 | ||
| 60 | |Reversible Algorithm| | |
| 61 | ||
| 62 | ||
| 63 | Parameters | |
| 64 | ---------- | |
| 65 | ||
| 66 | +-------------------+-----------------------------------+-----------------------------------+ | |
| 67 | | Parameter | Requirement | Description | | |
| 68 | +===================+===================================+===================================+ | |
| 69 | | ``Sequence``, | |Forward Sequence| | Sequences to transform. | | |
| 70 | | ``Seq1``, ``Seq2``| | | | |
| 71 | +-------------------+-----------------------------------+-----------------------------------+ | |
| 72 | | ``Op``, | |Lambda Expression| | A transformation. | | |
| 73 | | ``BinaryOp`` | | | | |
| 74 | +-------------------+-----------------------------------+-----------------------------------+ | |
| 75 | | ``In`` | |Inserter| | An inserter. | | |
| 76 | +-------------------+-----------------------------------+-----------------------------------+ | |
| 77 | ||
| 78 | ||
| 79 | Expression semantics | |
| 80 | -------------------- | |
| 81 | ||
| 82 | |Semantics disclaimer...| |Reversible Algorithm|. | |
| 83 | ||
| 84 | For any |Forward Sequence|\ s ``s``, ``s1`` and ``s2``, |Lambda Expression|\ s ``op`` and ``op2``, | |
| 85 | and an |Inserter| ``in``: | |
| 86 | ||
| 87 | .. parsed-literal:: | |
| 88 | ||
| 89 | typedef transform<s,op,in>::type r; | |
| 90 | ||
| 91 | :Return type: | |
| 92 | A type. | |
| 93 | ||
| 94 | :Postcondition: | |
| 95 | Equivalent to | |
| 96 | ||
| 97 | .. parsed-literal:: | |
| 98 | ||
| 99 | typedef lambda<op>::type f; | |
| 100 | typedef lambda<in::operation>::type in_op; | |
| 101 | ||
| 102 | typedef fold< | |
| 103 | s | |
| 104 | , in::state | |
| 105 | , bind< in_op, _1, bind<f, _2> > | |
| 106 | >::type r; | |
| 107 | ||
| 108 | ||
| 109 | .. parsed-literal:: | |
| 110 | ||
| 111 | typedef transform<s1,s2,op,in>::type r; | |
| 112 | ||
| 113 | :Return type: | |
| 114 | A type. | |
| 115 | ||
| 116 | :Postcondition: | |
| 117 | Equivalent to | |
| 118 | ||
| 119 | .. parsed-literal:: | |
| 120 | ||
| 121 | typedef lambda<op2>::type f; | |
| 122 | typedef lambda<in::operation>::type in_op; | |
| 123 | ||
| 124 | typedef fold< | |
| 125 | pair_view<s1,s2> | |
| 126 | , in::state | |
| 127 | , bind< | |
| 128 | in_op | |
| 129 | , _1 | |
| 130 | , bind<f, bind<first<>,_2>, bind<second<>,_2> > | |
| 131 | > | |
| 132 | >::type r; | |
| 133 | ||
| 134 | ||
| 135 | Complexity | |
| 136 | ---------- | |
| 137 | ||
| 138 | Linear. Exactly ``size<s>::value`` / ``size<s1>::value`` applications of | |
| 139 | ``op`` / ``op2`` and ``in::operation``. | |
| 140 | ||
| 141 | ||
| 142 | Example | |
| 143 | ------- | |
| 144 | ||
| 145 | .. parsed-literal:: | |
| 146 | ||
| 147 | typedef vector<char,short,int,long,float,double> types; | |
| 148 | typedef vector<char*,short*,int*,long*,float*,double*> pointers; | |
| 149 | typedef transform< types,boost::add_pointer<_1> >::type result; | |
| 150 | ||
| 151 | BOOST_MPL_ASSERT(( equal<result,pointers> )); | |
| 152 | ||
| 153 | ||
| 154 | See also | |
| 155 | -------- | |
| 156 | ||
| 157 | |Transformation Algorithms|, |Reversible Algorithm|, |reverse_transform|, |copy|, |replace_if| | |
| 158 | ||
| 159 | ||
| 160 |