| .. Metafunctions/Bitwise Operations//shift_right |
| |
| shift_right |
| =========== |
| |
| Synopsis |
| -------- |
| |
| .. parsed-literal:: |
| |
| template< |
| typename T |
| , typename Shift |
| > |
| struct shift_right |
| { |
| typedef |unspecified| type; |
| }; |
| |
| |
| |
| Description |
| ----------- |
| |
| Returns the result of bitwise *shift right* (``>>``) operation on ``T``. |
| |
| |
| Header |
| ------ |
| |
| .. parsed-literal:: |
| |
| #include <boost/mpl/shift_right.hpp> |
| #include <boost/mpl/bitwise.hpp> |
| |
| |
| Model of |
| -------- |
| |
| |Numeric Metafunction| |
| |
| |
| Parameters |
| ---------- |
| |
| +---------------+-------------------------------+---------------------------+ |
| | Parameter | Requirement | Description | |
| +===============+===============================+===========================+ |
| | ``T`` | |Integral Constant| | A value to shift. | |
| +---------------+-------------------------------+---------------------------+ |
| | ``Shift`` | Unsigned |Integral Constant| | A shift distance. | |
| +---------------+-------------------------------+---------------------------+ |
| |
| |Note:| |numeric metafunction note| |-- end note| |
| |
| |
| Expression semantics |
| -------------------- |
| |
| For arbitrary |Integral Constant| ``c`` and unsigned |Integral Constant| ``shift``: |
| |
| |
| .. parsed-literal:: |
| |
| typedef shift_right<c,shift>::type r; |
| |
| :Return type: |
| |Integral Constant|. |
| |
| :Semantics: |
| Equivalent to |
| |
| .. parsed-literal:: |
| |
| typedef integral_c< |
| c::value_type |
| , ( c::value >> shift::value ) |
| > r; |
| |
| .. .......................................................................... |
| |
| .. parsed-literal:: |
| |
| typedef shift_right<c,shift> r; |
| |
| :Return type: |
| |Integral Constant|. |
| |
| :Semantics: |
| Equivalent to |
| |
| .. parsed-literal:: |
| |
| struct r : shift_right<c,shift>::type {}; |
| |
| |
| Complexity |
| ---------- |
| |
| Amortized constant time. |
| |
| |
| Example |
| ------- |
| |
| .. parsed-literal:: |
| |
| typedef integral_c<unsigned,0> u0; |
| typedef integral_c<unsigned,1> u1; |
| typedef integral_c<unsigned,2> u2; |
| typedef integral_c<unsigned,8> u8; |
| |
| BOOST_MPL_ASSERT_RELATION( (shift_right<u0,u0>::value), ==, 0 ); |
| BOOST_MPL_ASSERT_RELATION( (shift_right<u1,u0>::value), ==, 1 ); |
| BOOST_MPL_ASSERT_RELATION( (shift_right<u1,u1>::value), ==, 0 ); |
| BOOST_MPL_ASSERT_RELATION( (shift_right<u2,u1>::value), ==, 1 ); |
| BOOST_MPL_ASSERT_RELATION( (shift_right<u8,u1>::value), ==, 4 ); |
| |
| |
| See also |
| -------- |
| |
| |Bitwise Operations|, |Numeric Metafunction|, |numeric_cast|, |shift_left|, |bitand_| |
| |
| |
| .. copyright:: Copyright © 2001-2009 Aleksey Gurtovoy and David Abrahams |
| Distributed under the Boost Software License, Version 1.0. (See accompanying |
| file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) |