Can you perform bitwise circular shift in c plus plus?

Answer 1

Yes. The following template examples will work for all unsigned integers of length 1, 2, 4 and 8 bytes.

#include <type_traits> // for std::is_unsigned

template<class T>

T circular_shift_left( register T x )

{

static_assert( std::is_unsigned<T>::value, "circular_shift_left(T): T must be unsigned!\n" );

T bit = x;

switch( sizeof( x ))

{

case(1): bit &= (T) 0x80; break;

case(2): bit &= (T) 0x8000; break;

case(4): bit &= (T) 0x80000000; break;

case(8): bit &= (T) 0x8000000000000000; break;

default: assert( 0 );

}

x <<= 1;

x |= bit ? 1 : 0;

return( x );

}

template<class T>

T circular_shift_right( register T x )

{

static_assert( std::is_unsigned<T>::value, "circular_shift_right(T): T must be unsigned!\n" );

T bit = x & (T) 0x1;

switch( sizeof( x ))

{

case(1): bit = bit ? (T) 0x80 : 0x0; break;

case(2): bit = bit ? (T) 0x8000 : 0x0; break;

case(4): bit = bit ? (T) 0x80000000 : 0x0; break;

case(8): bit = bit ? (T) 0x8000000000000000 : 0x0; break;

default: assert( 0 );

}

x >>= 1;

x |= bit;

return( x );

}