kget/core/bitset.h

   1 /***************************************************************************
   2  *   Copyright (C) 2005 by Joris Guisson                                   *
   3  *   joris.guisson@gmail.com                                               *
   4  *                                                                         *
   5  *   This program is free software; you can redistribute it and/or modify  *
   6  *   it under the terms of the GNU General Public License as published by  *
   7  *   the Free Software Foundation; either version 2 of the License, or     *
   8  *   (at your option) any later version.                                   *
   9  *                                                                         *
  10  *   This program is distributed in the hope that it will be useful,       *
  11  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
  12  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
  13  *   GNU General Public License for more details.                          *
  14  *                                                                         *
  15  *   You should have received a copy of the GNU General Public License     *
  16  *   along with this program; if not, write to the                         *
  17  *   Free Software Foundation, Inc.,                                       *
  18  *   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.             *
  19  ***************************************************************************/
  20 #ifndef BTBITSET_H
  21 #define BTBITSET_H
  22
  23 #include <kget_export.h>
  24
  25 /**
  26   * @author Joris Guisson
  27   * @brief Simple implementation of a BitSet
  28   *
  29   * Simple implementation of a BitSet, can only turn on and off bits.
  30   * BitSet's are used to indicate which chunks we have or not.
  31   */
  32 class KGET_EXPORT BitSet
  33 {
  34         quint32 num_bits,num_bytes;
  35         quint8* data;
  36         quint32 num_on;
  37 public:
  38         /**
  39           * Constructor.
  40           * @param num_bits The number of bits
  41           */
  42         BitSet(quint32 num_bits = 8);
  43
  44         /**
  45           * Manually set data.
  46           * @param data The data
  47           * @param num_bits The number of bits
  48           */
  49         BitSet(const quint8* data,quint32 num_bits);
  50
  51         /**
  52           * Copy constructor.
  53           * @param bs BitSet to copy
  54           * @return
  55           */
  56         BitSet(const BitSet & bs);
  57         virtual ~BitSet();
  58
  59         /// See if the BitSet is null
  60         bool isNull() const {return num_bits == 0;}
  61
  62         /**
  63           * Get the value of a bit, false means 0, true 1.
  64           * @param i Index of Bit
  65           */
  66         bool get(quint32 i) const;
  67
  68         /**
  69           * Set the value of a bit, false means 0, true 1.
  70           * @param i Index of Bit
  71           * @param on False means 0, true 1
  72           */
  73         void set(quint32 i,bool on);
  74
  75         /// Set all bits on or off
  76         void setAll(bool on);
  77
  78         quint32 getNumBytes() const {return num_bytes;}
  79         quint32 getNumBits() const {return num_bits;}
  80         const quint8* getData() const {return data;}
  81         quint8* getData() {return data;}
  82
  83         /// Get the number of on bits
  84         quint32 numOnBits() const {return num_on;}
  85
  86         /**
  87           * Set all bits to 0
  88           */
  89         void clear();
  90
  91         /**
  92           * or this BitSet with another.
  93           * @param other The other BitSet
  94           */
  95         void orBitSet(const BitSet & other);
  96
  97         /**
  98           * Assignment operator.
  99           * @param bs BitSet to copy
 100           * @return *this
 101           */
 102         BitSet & operator = (const BitSet & bs);
 103
 104         /// Check if all bit are set to 1
 105         bool allOn() const;
 106
 107         /**
 108           * Check for equality of bitsets
 109           * @param bs BitSet to compare
 110           * @return true if equal
 111           */
 112         bool operator == (const BitSet & bs);
 113
 114         /**
 115           * Opposite of operator ==
 116           */
 117         bool operator != (const BitSet & bs) {return ! operator == (bs);}
 118
 119         static BitSet null;
 120 };
 121
 122 inline bool BitSet::get(quint32 i) const
 123 {
 124         if (i >= num_bits)
 125                 return false;
 126
 127         quint32 byte = i / 8;
 128         quint32 bit = i % 8;
 129         quint8 b = data[byte] & (0x01 << (7 - bit));
 130         return b != 0x00;
 131 }
 132
 133 inline void BitSet::set(quint32 i,bool on)
 134 {
 135         if (i >= num_bits)
 136                 return;
 137
 138         quint32 byte = i / 8;
 139         quint32 bit = i % 8;
 140         if (on && !get(i))
 141         {
 142                 num_on++;
 143                 data[byte] |= (0x01 << (7 - bit));
 144         }
 145         else if (!on && get(i))
 146         {
 147                 num_on--;
 148                 quint8 b = (0x01 << (7 - bit));
 149                 data[byte] &= (~b);
 150         }
 151 }
 152
 153 #endif