- Joined
- Jul 20, 2009
- Messages
- 835
This is my humble bit operation library. Commented inside. Please comment. 
JASS:
library BitOperations initializer Init
globals
// Warcraft 3 uses 32-bit signed integers.
private constant integer BITS_IN_INTEGER = 32
private integer array Pow2[BITS_IN_INTEGER]
endglobals
// BitwiseNot(a) = ~a in C++
function BitwiseNot takes integer a returns integer
return -1-x
endfunction
// LeftShift(a,bitCount) = a << bitCount in C++
function LeftShift takes integer a, integer bitCount returns integer
return a*Pow2[bitCount]
endfunction
// RightShift(a,bitCount) = a >> bitCount in C++
function RightShift takes integer a, integer bitCount returns integer
return a/Pow2[bitCount]
endfunction
// BitwiseAnd(a,b) = a&b in C++
function BitwiseAnd takes integer a, integer b returns integer
local integer aBit // Bit of a;
local integer bBit // Bit of b;
local integer rBit // Bit of result
local integer r = 0 // result
loop
exitwhen i==BITS_IN_INTEGER
set aBit = ModuloInteger(a, 2)
set bBit = ModuloInteger(b, 2)
if aBit == 1 and bBit == 1 then
set rBit = 1
else
set Bit = 0
endif
set r = r + LeftShift(rBit,i)
set a = a / 2
set b = b / 2
set i = i + 1
endloop
return r
endfunction
// BitwiseOr(a,b) = a|b in C++
function BitwiseOr takes integer a, integer b returns integer
local integer aBit // Bit of a
local integer bBit // Bit of b
local integer rBit // Bit of result
local integer r = 0 // result
loop
exitwhen i==BITS_IN_INTEGER
set aBit = ModuloInteger(a, 2)
set bBit = ModuloInteger(b, 2)
if aBit == 1 or bBit == 1 then
set rBit = 1
else
set rBit = 0
endif
set r = r + LeftShift(rBit,i)
set a = a / 2
set b = b / 2
set i = i + 1
endloop
return r
endfunction
// BitwiseXor(a,b) = a^b in C++
function BitwiseXor takes integer a, integer b returns integer
local integer aBit // Bit of a
local integer bBit // Bit of b
local integer rBit // Bit of result
local integer r = 0 // result
loop
exitwhen i==BITS_IN_INTEGER
set aBit = ModuloInteger(a, 2)
set bBit = ModuloInteger(b, 2)
if aBit != bBit then
set rBit = 1
else
set rBit = 0
endif
set r = r + LeftShift(rBit,i)
set a = a / 2
set b = b / 2
set i = i + 1
endloop
return r
endfunction
private function Init takes nothing returns nothing
local integer i = 1
// Pre-init the power of two array to speed up the system.
set Pow2[0] = 1
loop
exitwhen i > BITS_IN_INTEGER-1
set Pow2[i] = Pow2[i-1]*2
set i = i + 1
endloop
endfunction
endlibrary
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