bits64.go raw

   1  package bits
   2  
   3  // IsOn returns true if *all* bits set in 'bits' are set in 'mask'.
   4  func IsOn64(mask, bits uint64) bool {
   5  	return mask&bits == bits
   6  }
   7  
   8  // IsAnyOn returns true if *any* bit set in 'bits' is set in 'mask'.
   9  func IsAnyOn64(mask, bits uint64) bool {
  10  	return mask&bits != 0
  11  }
  12  
  13  // Mask returns a T with all of the given bits set.
  14  func Mask64(is ...int) uint64 {
  15  	ret := uint64(0)
  16  	for _, i := range is {
  17  		ret |= MaskOf64(i)
  18  	}
  19  	return ret
  20  }
  21  
  22  // MaskOf is like Mask, but sets only a single bit (more efficiently).
  23  func MaskOf64(i int) uint64 {
  24  	return uint64(1) << uint64(i)
  25  }
  26  
  27  // IsPowerOfTwo returns true if v is power of 2.
  28  func IsPowerOfTwo64(v uint64) bool {
  29  	if v == 0 {
  30  		return false
  31  	}
  32  	return v&(v-1) == 0
  33  }
  34