boost的integer/integer_mask.hpp仅仅做了单个位的bit mask
要多个位必须写很多遍high_bit_mask_t
使用low_bits_mask_t也不能完全解决问题
所以自己用Typelist的那种写法写了一个

用法举例
bit_mask<INT_LIST_2(2, 3)>::value返回一个值，该值的第2、3位被置为1
其余位为0

namespace ?multi_bit_mask
{
???? namespace ?details
???? {

???????? namespace ?storage_definition
???????? {
????????????template? < int ?Bit >
???????????? struct ?bit_storage
???????????? {
????????????????typedef?typename?bit_storage < Bit? - ? 1 > ::storage_type?storage_type;
????????????} ;

???????????? // ~~~~~~~~~~~~~~~platform?dependency,?modify?it?when?things?go?wrong~~~~~~~~~~~~~~~~~~~~~~~~~~

????????????typedef?unsigned? int ?smallest_storage_type;

????????????template? <>
???????????? struct ?bit_storage < 0 >
???????????? {
????????????????typedef?smallest_storage_type?storage_type;
????????????} ;

????????????template? <>
???????????? struct ?bit_storage < 32 >
???????????? {
????????????????typedef?unsigned? long ? long ?storage_type;
????????????} ;

???????????? // disable?the?65th?bit
????????????template? <>
???????????? struct ?bit_storage < 64 >
???????????? {
????????????????typedef? void ?storage_type;
????????????} ;

????????????

???????????? // ~~~~~~~~~~~~~~~~~~~~~~~~~~end?of?platform?dependency~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
????????}


???????? namespace ?int_list_definition
???????? {
????????????template? < unsigned? int ?N,?typename?Next >
???????????? struct ?int_list
???????????? {
????????????????typedef?typename?storage_definition::bit_storage < N > ::storage_type?storage_type;
???????????????? static ? const ?storage_type?value? = ?N;
????????????????typedef?Next?next;
????????????} ;

???????????? struct ?null_type {} ;

????????????

????????????template < typename?T1,?typename?T2,? bool ?is_first >
???????????? struct ?selector
???????????? {
????????????????typedef?T1?type;
????????????} ;

????????????template < typename?T1,?typename?T2 >
???????????? struct ?compare_type
???????????? {
???????????????? const ? static ? bool ?is_larger? = ? sizeof (T1)? > ? sizeof (T2);
????????????????typedef?typename?selector < T1,?T2,?is_larger > ::type?large_type;
????????????????typedef?typename?selector < T1,?T2,? ! is_larger > ::type?small_type;
????????????} ;

????????????

????????????template < typename?T1,?typename?T2 >
???????????? struct ?selector < T1,?T2,? false >
???????????? {
????????????????typedef?T2?type;
????????????} ;

????????????template? < typename?List,? int ?N >
???????????? struct ?delete_from
???????????? {
???????????? private :
????????????????typedef?typename?delete_from < typename?List::next,?N > ::result_type?deleted_next;
???????????? public :
????????????????typedef?int_list < List::value,?deleted_next > ?result_type;
????????????} ;

????????????template? < int ?N >
???????????? struct ?delete_from < null_type,?N >
???????????? {
????????????????typedef?null_type?result_type;
????????????} ;

????????????template? < typename?Next,? int ?N >
???????????? struct ?delete_from < int_list < N,?Next > ,?N >
???????????? {
????????????????typedef?typename?delete_from < Next,?N > ::result_type?result_type;
????????????} ;


????????????template? < typename?List >
???????????? struct ?make_unique
???????????? {
???????????? private :
????????????????typedef?typename?make_unique < typename?List::next > ::result_type?uniqued_next;
????????????????typedef?typename?delete_from < uniqued_next,?List::value > ::result_type?prepared_next;
???????????? public :
????????????????typedef?int_list < List::value,?prepared_next > ?result_type;
????????????} ;

????????????template? <>
???????????? struct ?make_unique < null_type >
???????????? {
????????????????typedef?null_type?result_type;
????????????} ;
????????}

????????template? < typename?List >
???????? class ?find_largest_storage
???????? {
????????????typedef?typename?find_largest_storage < typename?List::next > ::storage_type?T1;
????????????typedef?typename?storage_definition::bit_storage < List::value > ::storage_type?T2;
???????? public :
????????????typedef?typename?int_list_definition::compare_type < T1,?T2 > ::large_type?storage_type;
????????} ;

????????template? <>
???????? class ?find_largest_storage < int_list_definition::null_type >
???????? {
???????? public :
????????????typedef?storage_definition::smallest_storage_type?storage_type;
????????} ;
????}


????template? < int ?N >
???? struct ?single_bit_mask
???? {
????????typedef?typename?details::storage_definition::bit_storage < N > ::storage_type?storage_type;
???????? static ? const ?storage_type?value?
???????????? = ?static_cast < storage_type > (single_bit_mask < N? - ? 1 > ::value)? * ? 2 ;
????} ;

????template? <>
???? struct ?single_bit_mask < 0 >
???? {
????????typedef?details::storage_definition::bit_storage < 0 > ::storage_type?storage_type;
???????? static ? const ?storage_type?value? = ? 1 ;
????} ;

????


????template? < typename?List >
???? struct ?bit_mask
???? {
???? private :
????????typedef?typename?details::int_list_definition::make_unique < List > ::result_type?List_;
???? public :

????????typedef?typename?details::find_largest_storage < List_ > ::storage_type?storage_type;
????
???????? static ? const ?storage_type?value?
???????????? = ?static_cast < storage_type > (single_bit_mask < List_::value > ::value)?
???????????? + ?static_cast < storage_type > (bit_mask < typename?List_::next > ::value);
????} ;

????template? <>
???? struct ?bit_mask < details::int_list_definition::null_type >
???? {
????????typedef?details::storage_definition::bit_storage < 0 > ::storage_type?storage_type;
???????? static ? const ?storage_type?value? = ? 0 ;
????} ;


????typedef?multi_bit_mask::details::int_list_definition::null_type?null_type;

????template? < int ?N,?typename?Next >
???? struct ?int_list_t?:? public ?multi_bit_mask::details::int_list_definition::int_list < N,?Next > ? {} ;

???? #define ?INT_LIST_1(n1)?multi_bit_mask::int_list_t<n1,?multi_bit_mask::null_type>
???? #define ?INT_LIST_2(n1,?n2)?multi_bit_mask::int_list_t<n1,?INT_LIST_1(n2)?>?
???? #define ?INT_LIST_3(n1,?n2,?n3)?multi_bit_mask::int_list_t<n1,?INT_LIST_2(n2,?n3)?>?
???? #define ?INT_LIST_4(n1,?n2,?n3,?n4)?multi_bit_mask::int_list_t<n1,?INT_LIST_3(n2,?n3,?n4)?>?
???? #define ?INT_LIST_5(n1,?n2,?n3,?n4,?n5)?multi_bit_mask::int_list_t<n1,?INT_LIST_4(n2,?n3,?n4,?n5)?>?
???? #define ?INT_LIST_6(n1,?n2,?n3,?n4,?n5,?n6)?multi_bit_mask::int_list_t<n1,?INT_LIST_5(n2,?n3,?n4,?n5,?n6)?>?
???? #define ?INT_LIST_7(n1,?n2,?n3,?n4,?n5,?n6,?n7)?multi_bit_mask::int_list_t<n1,?INT_LIST_6(n2,?n3,?n4,?n5,?n6,?n7)?>?
???? #define ?INT_LIST_8(n1,?n2,?n3,?n4,?n5,?n6,?n7,?n8)?multi_bit_mask::int_list_t<n1,?INT_LIST_7(n2,?n3,?n4,?n5,?n6,?n7,?n8)?>?
????
}

sample

#include? < iostream >
#include? " multi_bit_mask.h "
using ? namespace ?std;
int ?main()
{
????cout? << ?multi_bit_mask::bit_mask < INT_LIST_1( 1 ) > ::value? << ?endl;
????cout? << ?multi_bit_mask::bit_mask < INT_LIST_5( 0 ,? 1 ,? 2 ,? 3 ,? 4 ) > ::value? << ?endl;
????cout? << ?multi_bit_mask::bit_mask < INT_LIST_7( 0 ,? 1 ,? 2 ,? 3 ,? 4 ,? 4 ,? 2 ) > ::value? << ?endl;
????