[SOLVED] Bitwise: more compact code

isotonic · **Author**

Need help for bitwise operations.

PHP Code:


			
#define VIP_A (1<<0)
#define VIP_Z (1<<6)
 
new giVipFlags[32]
 
public XXX(id) {
  giVipFlags[id] |= VIP_A  // set VIP_A flag
  giVipFlags[id] &= ~VIP_Z // clear VIP_Z flag
}

Can public XXX(id) do the same using 1 line of code not 2?

jimaway · 10-18-2012 , 16:51 Re: Bitwise: more compact code

if you're sure that VIP_A is always unset and VIP_Z is always set in that function then you could use this i suppose:

giVipFlags[id] ^= (VIP_A|VIP_Z)

isotonic · 10-18-2012 , 17:35 Re: Bitwise: more compact code

Could you explain step-by-step that code?

**Bugsy** · 10-18-2012 , 20:22 Re: Bitwise: more compact code

Unfortunately, to my knowledge, you cannot add a bit and remove a bit in a single operation. OR will always set the bit(s) that exist in either operand and AND/NOT will remove the bit(s) that exists in the comparing operand.

Don't be concerned with the number of lines in your code, be concerned about the amount of actual code, which in this case can be reduced using macros.

**Emp`** · 10-18-2012 , 20:55 Re: Bitwise: more compact code

Code:

iFlags = ( iFlags & ~(1) ) | (2)
iFlags = ( iFlags | (2) ) & ~(1)

Both should do it, but see Bugsy's notes above.

Liverwiz · 10-19-2012 , 19:22 Re: Bitwise: more compact code

Quote:

Originally Posted by isotonic

Need help for bitwise operations.

PHP Code:


			
#define VIP_A (1<<0)

#define VIP_Z (1<<6)

 

new giVipFlags[32]

 

public XXX(id) {

  giVipFlags[id] |= VIP_A  // set VIP_A flag

  giVipFlags[id] &= ~VIP_Z // clear VIP_Z flag

}

Can public XXX(id) do the same using 1 line of code not 2?

SURE!

Code:

giVipFlags[id] |= VIP_A; giVipFlags[id] &= ~VIP_Z

isotonic · 10-19-2012 , 19:40 Re: Bitwise: more compact code

Quote:

Originally Posted by Emp`

Code:

iFlags = ( iFlags & ~(1) ) | (2)
iFlags = ( iFlags | (2) ) & ~(1)

Emp` did I understand you properly?

PHP Code:


			
giVipFlags[id] = ( giVipFlags[id] | VIP_A ) &~ VIP_Z

--

Nice joke Liverwiz ;)