topical media & game development
[] readme course(s) preface I 1 2 II 3 4 III 5 6 7 IV 8 9 10 V 11 12 afterthought(s) appendix reference(s) example(s) resource(s) _

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lib-as-de-polygonal-ds-BitVector.ax

lib-as-de-polygonal-ds-BitVector.ax (swf ) [ flash ] flex
Copyright (c) Michael Baczynski 2007 http://lab.polygonal.de/ds/ This software is distributed under licence. Use of this software implies agreement with all terms and conditions of the accompanying software licence. 

  
  package de.polygonal.ds
  {
A bitvector. A bitvector is meant to condense bit values (or booleans) into an array as close as possible so that no space is wasted. 

  
          public class @ax-lib-as-de-polygonal-ds-BitVector
          {
                  private var _bits:Array;
                  private var _arrSize:int;
                  private var _bitSize:int;
Creates a bitvector with a given number of bits. Each cell holds a 31-bit signed integer.
parameter: bits The total number of bits. 

  
                  public function @ax-lib-as-de-polygonal-ds-BitVector(bits:int)
                  {
                          _bits = [];
                          _arrSize = 0;
                          
                          resize(bits);
                  }
The total number of bits. 

  
                  public function get bitCount():int
                  {
                          return _arrSize * 31;
                  }
The total number of cells. 

  
                  public function get cellCount():int
                  {
                          return _arrSize;
                  }
Gets a bit from a given index.
parameter: index The index of the bit. 

  
                  public function getBit(index:int):int
                  {
                          var bit:int = index % 31;
                          return (_bits[(index / 31) >> 0] & (1 << bit)) >> bit;
                  }
Sets a bit at a given index.
parameter: index The index of the bit.
parameter: b The boolean flag to set. 

  
                  public function setBit(index:int, b:Boolean):void
                  {
                          var cell:int = index / 31;
                          var mask:int = 1 << index % 31;
                          _bits[cell] = b ? (_bits[cell] | mask) : (_bits[cell] & (~mask));
                  }
Resizes the bitvector to an appropriate number of bits.
parameter: size The total number of bits. 

  
                  public function resize(size:int):void
                  {
                          if (size == _bitSize) return;
                          _bitSize = size;
                          
                          //convert the bit-size to integer-size
                          if (size % 31 == 0)
                                  size /= 31;
                          else
                                  size = (size / 31) + 1;
                          
                          if (size < _arrSize)
                          {
                                  _bits.splice(size);
                                  _arrSize = size;
                          }
                          else
                          {
                                  _bits = _bits.concat(new Array(size - _arrSize));
                                  _arrSize = _bits.length;
                          }
                  }
Resets all bits to 0; 

  
                  public function clear():void
                  {
                          var k:int = _bits.length;
                          for (var i:int = 0; i < k; i++)
                                  _bits[i] = 0;
                  }
Sets each bit to 1. 

  
                  public function setAll():void
                  {
                          var k:int = _bits.length;
                          for (var i:int = 0; i < k; i++)
                                  _bits[i] = int.MAX_VALUE;
                  }
Returns a string representing the current object. 

  
                  public function toString():String
                  {
                          return "[@ax-lib-as-de-polygonal-ds-BitVector, size=" + _bitSize + "]";
                  }
          }
  }
[] readme course(s) preface I 1 2 II 3 4 III 5 6 7 IV 8 9 10 V 11 12 afterthought(s) appendix reference(s) example(s) resource(s) _

(C) Æliens 20/2/2008

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