Helpers.cpp

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// MIT License
//
// Copyright (c) 2022 Ian Parberry
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// SOFTWARE.
 
#include "Helpers.h"
 
 
bool odd(const UINT n){
  return n & 1; //obvious, really
} //odd
 
 
bool IsPowerOf2(const UINT n){
  return n && !(n & (n - 1)); //tricksy
} //IsPowerOf2
 
 
UINT CeilLog2(const UINT n){ 
  if(n == 0)return 0; //safety
 
  DWORD k = 0; //for index of most significant 1
  _BitScanReverse(&k, n); //find index of most significant 1
 
  return IsPowerOf2(n)? k: k + 1;
} //NextPowerOf2