ctSwap

void ctSwap(T)(uint  doSwap,  ref  T a,  ref  T b) if (is(T ==  ubyte)  ||  is(T ==  ushort)  ||  is(T ==  uint)  ||  is(T ==  ulong))

pure nothrow @nogc @safe

Swaps two values conditionally in constant time.

If doSwap is non-zero, swaps the values of a and b. If doSwap is 0, leaves a and b unchanged. The operation is performed using XOR without branching.

Parameters

`doSwap`	Swap flag (0 = no swap, non-zero = swap).
`a`	First value (may be modified).
`b`	Second value (may be modified).