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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. *
***************************************************************************/
#ifndef BTBITSET_H
#define BTBITSET_H
#include "constants.h"
namespace bt
{
/**
* @author Joris Guisson
* @brief Simple implementation of a BitSet
*
* Simple implementation of a BitSet, can only turn on and off bits.
* BitSet's are used to indicate which chunks we have or not.
*/
class BitSet
{
Uint32 num_bits,num_bytes;
Uint8* data;
Uint32 num_on;
public:
/**
* Constructor.
* @param num_bits The number of bits
*/
BitSet(Uint32 num_bits = 8);
/**
* Manually set data.
* @param data The data
* @param num_bits The number of bits
*/
BitSet(const Uint8* data,Uint32 num_bits);
/**
* Copy constructor.
* @param bs BitSet to copy
* @return
*/
BitSet(const BitSet & bs);
virtual ~BitSet();
/// See if the BitSet is null
bool isNull() const {return num_bits == 0;}
/**
* Get the value of a bit, false means 0, true 1.
* @param i Index of Bit
*/
bool get(Uint32 i) const;
/**
* Set the value of a bit, false means 0, true 1.
* @param i Index of Bit
* @param on False means 0, true 1
*/
void set(Uint32 i,bool on);
/// Set all bits on or off
void setAll(bool on);
Uint32 getNumBytes() const {return num_bytes;}
Uint32 getNumBits() const {return num_bits;}
const Uint8* getData() const {return data;}
Uint8* getData() {return data;}
/// Get the number of on bits
Uint32 numOnBits() const {return num_on;}
/**
* Set all bits to 0
*/
void clear();
/**
* or this BitSet with another.
* @param other The other BitSet
*/
void orBitSet(const BitSet & other);
/**
* Assignment operator.
* @param bs BitSet to copy
* @return *this
*/
BitSet & operator = (const BitSet & bs);
/// Check if all bit are set to 1
bool allOn() const;
/**
* Check for equality of bitsets
* @param bs BitSet to compare
* @return true if equal
*/
bool operator == (const BitSet & bs);
/**
* Opposite of operator ==
*/
bool operator != (const BitSet & bs) {return ! operator == (bs);}
static BitSet null;
};
inline bool BitSet::get(Uint32 i) const
{
if (i >= num_bits)
return false;
Uint32 byte = i / 8;
Uint32 bit = i % 8;
Uint8 b = data[byte] & (0x01 << (7 - bit));
return b != 0x00;
}
inline void BitSet::set(Uint32 i,bool on)
{
if (i >= num_bits)
return;
Uint32 byte = i / 8;
Uint32 bit = i % 8;
if (on && !get(i))
{
num_on++;
data[byte] |= (0x01 << (7 - bit));
}
else if (!on && get(i))
{
num_on--;
Uint8 b = (0x01 << (7 - bit));
data[byte] &= (~b);
}
}
}
#endif
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