bitset.cpp

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/***************************************************************************
 *   Copyright (C) 2005 by Joris Guisson                                   *
 *   joris.guisson@gmail.com                                               *
 *                                                                         *
 *   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.,                                       *
 *   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.          *
 ***************************************************************************/
#include "bitset.h"
#include <algorithm>
#include <string.h>

BitSet BitSet::null;

BitSet::BitSet(quint32 num_bits) : num_bits(num_bits),data(0)
{
    num_bytes = (num_bits / 8) + ((num_bits % 8 > 0) ? 1 : 0);
    data = new quint8[num_bytes];
    std::fill(data,data+num_bytes,0x00);
    num_on = 0;
}

BitSet::BitSet(const quint8* d,quint32 num_bits)  : num_bits(num_bits),data(0)
{
    num_bytes = (num_bits / 8) + ((num_bits % 8 > 0) ? 1 : 0);
    data = new quint8[num_bytes];
    memcpy(data,d,num_bytes);
    num_on = 0;
    quint32 i = 0;
    while (i < num_bits)
    {
        if (get(i))
            num_on++;
        i++;
    }
}

BitSet::BitSet(const BitSet & bs) : num_bits(bs.num_bits),num_bytes(bs.num_bytes),data(0),num_on(bs.num_on)
{
    data = new quint8[num_bytes];
    std::copy(bs.data,bs.data+num_bytes,data);
}
        
BitSet::~BitSet()
{
    delete [] data;
}



BitSet & BitSet::operator = (const BitSet & bs)
{
    if (data)
        delete [] data;
    num_bytes = bs.num_bytes;
    num_bits = bs.num_bits;
    data = new quint8[num_bytes];
    std::copy(bs.data,bs.data+num_bytes,data);
    num_on = bs.num_on;
    return *this;
}

void BitSet::setAll(bool on)
{
    std::fill(data,data+num_bytes,on ? 0xFF : 0x00);
    num_on = on ? num_bits : 0;
}

void BitSet::getContinuousRange(qint32 *start, qint32 *end, bool on)
{
    *start = -1;
    *end = -1;

    const bool nothingFound = on ? allOff() : allOn();
    if (nothingFound) {
        return;
    }

    const bool everythingMatches = on ? allOn() : allOff();
    if (everythingMatches) {
        *start = 0;
        *end = num_bits -1;
        return;
    }

    for (quint32 i = 0; i < num_bits; ++i) {
        if (get(i) == on) {
            if (*start == -1) {
                *start = i;
            }
            *end = i;
        } else {
            if (*start != -1) {
                return;
            }
        }
    }
}

void BitSet::clear()
{
    setAll(false);
}

void BitSet::orBitSet(const BitSet & other)
{
    quint32 i = 0;
    while (i < num_bits)
    {
        bool val = get(i) || other.get(i);
        set(i,val);
        i++;
    }
}

bool BitSet::allOn() const
{
    return num_on == num_bits;
}

bool BitSet::allOff() const
{
    return !num_on;
}

bool BitSet::operator == (const BitSet & bs)
{
    if (this->getNumBits() != bs.getNumBits())
        return false;

    return memcmp(data,bs.data,num_bytes) == 0;
}