Utils.cpp

/*
 *   Copyright (C) 2015 by Jonathan Naylor G4KLX
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include "Utils.h"

const uint8_t BITS_TABLE[] = {
#   define B2(n) n,     n+1,     n+1,     n+2
#   define B4(n) B2(n), B2(n+1), B2(n+1), B2(n+2)
#   define B6(n) B4(n), B4(n+1), B4(n+1), B4(n+2)
    B6(0), B6(1), B6(1), B6(2)
};

uint8_t countBits8(uint8_t bits)
{
  return BITS_TABLE[bits];
}

uint8_t countBits32(uint32_t bits)
{
  uint8_t* p = (uint8_t*)&bits;
  uint8_t n = 0U;
  n += BITS_TABLE[p[0U]];
  n += BITS_TABLE[p[1U]];
  n += BITS_TABLE[p[2U]];
  n += BITS_TABLE[p[3U]];
  return n;
}

uint8_t countBits64(uint64_t bits)
{
  uint8_t* p = (uint8_t*)&bits;
  uint8_t n = 0U;
  n += BITS_TABLE[p[0U]];
  n += BITS_TABLE[p[1U]];
  n += BITS_TABLE[p[2U]];
  n += BITS_TABLE[p[3U]];
  n += BITS_TABLE[p[4U]];
  n += BITS_TABLE[p[5U]];
  n += BITS_TABLE[p[6U]];
  n += BITS_TABLE[p[7U]];
  return n;
}