BitVector32 Structure (System.Collections.Specialized)

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Microsoft Visual Studio 2008/.NET Framework 3.5

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.NET Framework Class Library

BitVector32 Structure

Provides a simple structure that stores Boolean values and small integers in 32 bits of memory.

Namespace: System.Collections.Specialized
Assembly: System (in System.dll)

Syntax

Visual Basic (Declaration)

Public Structure BitVector32

Visual Basic (Usage)

Dim instance As BitVector32

public struct BitVector32

Visual C++

public value class BitVector32

JScript

JScript supports the use of structures, but not the declaration of new ones.

Remarks

BitVector32 is more efficient than BitArray for Boolean values and small integers that are used internally. A BitArray can grow indefinitely as needed, but it has the memory and performance overhead that a class instance requires. In contrast, a BitVector32 uses only 32 bits.

A BitVector32 structure can be set up to contain either sections for small integers or bit flags for Booleans, but not both. A BitVector32..::.Section is a window into the BitVector32 and is composed of the smallest number of consecutive bits that can contain the maximum value specified in CreateSection. For example, a section with a maximum value of 1 is composed of only one bit, whereas a section with a maximum value of 5 is composed of three bits. You can create a BitVector32..::.Section with a maximum value of 1 to serve as a Boolean, thereby allowing you to store integers and Booleans in the same BitVector32.

Some members can be used for a BitVector32 that is set up as sections, while other members can be used for one that is set up as bit flags. For example, the BitVector32..::.Item property is the indexer for a BitVector32 that is set up as sections, and the BitVector32..::.Item property is the indexer for a BitVector32 that is set up as bit flags. CreateMask creates a series of masks that can be used to access individual bits in a BitVector32 that is set up as bit flags.

Using a mask on a BitVector32 that is set up as sections might cause unexpected results.

Examples

The following code example uses a BitVector32 as a collection of bit flags.

Visual Basic

Imports System
Imports System.Collections.Specialized

Public Class SamplesBitVector32

   Public Shared Sub Main()

      ' Creates and initializes a BitVector32 with all bit flags set to FALSE.
      Dim myBV As New BitVector32(0)

      ' Creates masks to isolate each of the first five bit flags.
      Dim myBit1 As Integer = BitVector32.CreateMask()
      Dim myBit2 As Integer = BitVector32.CreateMask(myBit1)
      Dim myBit3 As Integer = BitVector32.CreateMask(myBit2)
      Dim myBit4 As Integer = BitVector32.CreateMask(myBit3)
      Dim myBit5 As Integer = BitVector32.CreateMask(myBit4)

      ' Sets the alternating bits to TRUE.
      Console.WriteLine("Setting alternating bits to TRUE:")
      Console.WriteLine("   Initial:         {0}", myBV.ToString())
      myBV(myBit1) = True
      Console.WriteLine("   myBit1 = TRUE:   {0}", myBV.ToString())
      myBV(myBit3) = True
      Console.WriteLine("   myBit3 = TRUE:   {0}", myBV.ToString())
      myBV(myBit5) = True
      Console.WriteLine("   myBit5 = TRUE:   {0}", myBV.ToString())
   End Sub 'Main 
End Class 'SamplesBitVector32


' This code produces the following output.
'
' Setting alternating bits to TRUE:
'    Initial:         BitVector32{00000000000000000000000000000000}
'    myBit1 = TRUE:   BitVector32{00000000000000000000000000000001}
'    myBit3 = TRUE:   BitVector32{00000000000000000000000000000101}
'    myBit5 = TRUE:   BitVector32{00000000000000000000000000010101}

using System;
using System.Collections.Specialized;


public class SamplesBitVector32  {

   public static void Main()  {

      // Creates and initializes a BitVector32 with all bit flags set to FALSE.
      BitVector32 myBV = new BitVector32( 0 );

      // Creates masks to isolate each of the first five bit flags.
      int myBit1 = BitVector32.CreateMask();
      int myBit2 = BitVector32.CreateMask( myBit1 );
      int myBit3 = BitVector32.CreateMask( myBit2 );
      int myBit4 = BitVector32.CreateMask( myBit3 );
      int myBit5 = BitVector32.CreateMask( myBit4 );

      // Sets the alternating bits to TRUE.
      Console.WriteLine( "Setting alternating bits to TRUE:" );
      Console.WriteLine( "   Initial:         {0}", myBV.ToString() );
      myBV[myBit1] = true;
      Console.WriteLine( "   myBit1 = TRUE:   {0}", myBV.ToString() );
      myBV[myBit3] = true;
      Console.WriteLine( "   myBit3 = TRUE:   {0}", myBV.ToString() );
      myBV[myBit5] = true;
      Console.WriteLine( "   myBit5 = TRUE:   {0}", myBV.ToString() );

   }

}

/*
This code produces the following output.

Setting alternating bits to TRUE:
   Initial:         BitVector32{00000000000000000000000000000000}
   myBit1 = TRUE:   BitVector32{00000000000000000000000000000001}
   myBit3 = TRUE:   BitVector32{00000000000000000000000000000101}
   myBit5 = TRUE:   BitVector32{00000000000000000000000000010101}


*/

Visual C++

#using <system.dll>

using namespace System;
using namespace System::Collections::Specialized;
int main()
{

   // Creates and initializes a BitVector32 with all bit flags set to FALSE.
   BitVector32 myBV(0);

   // Creates masks to isolate each of the first five bit flags.
   int myBit1 = BitVector32::CreateMask();
   int myBit2 = BitVector32::CreateMask( myBit1 );
   int myBit3 = BitVector32::CreateMask( myBit2 );
   int myBit4 = BitVector32::CreateMask( myBit3 );
   int myBit5 = BitVector32::CreateMask( myBit4 );

   // Sets the alternating bits to TRUE.
   Console::WriteLine( "Setting alternating bits to TRUE:" );
   Console::WriteLine( "   Initial:       {0}", myBV );
   myBV[ myBit1 ] = true;
   Console::WriteLine( "   myBit1 = TRUE: {0}", myBV );
   myBV[ myBit3 ] = true;
   Console::WriteLine( "   myBit3 = TRUE: {0}", myBV );
   myBV[ myBit5 ] = true;
   Console::WriteLine( "   myBit5 = TRUE: {0}", myBV );
}

/*
This code produces the following output.

Setting alternating bits to TRUE:
Initial:         BitVector32 {00000000000000000000000000000000}
myBit1 = TRUE:   BitVector32 {00000000000000000000000000000001}
myBit3 = TRUE:   BitVector32 {00000000000000000000000000000101}
myBit5 = TRUE:   BitVector32 {00000000000000000000000000010101}


*/

The following code example uses a BitVector32 as a collection of sections.

Visual Basic

Imports System
Imports System.Collections.Specialized

Public Class SamplesBitVector32

   Public Shared Sub Main()

      ' Creates and initializes a BitVector32.
      Dim myBV As New BitVector32(0)

      ' Creates four sections in the BitVector32 with maximum values 6, 3, 1, and 15.
      ' mySect3, which uses exactly one bit, can also be used as a bit flag.
      Dim mySect1 As BitVector32.Section = BitVector32.CreateSection(6)
      Dim mySect2 As BitVector32.Section = BitVector32.CreateSection(3, mySect1)
      Dim mySect3 As BitVector32.Section = BitVector32.CreateSection(1, mySect2)
      Dim mySect4 As BitVector32.Section = BitVector32.CreateSection(15, mySect3)

      ' Displays the values of the sections.
      Console.WriteLine("Initial values:")
      Console.WriteLine(ControlChars.Tab + "mySect1: {0}", myBV(mySect1))
      Console.WriteLine(ControlChars.Tab + "mySect2: {0}", myBV(mySect2))
      Console.WriteLine(ControlChars.Tab + "mySect3: {0}", myBV(mySect3))
      Console.WriteLine(ControlChars.Tab + "mySect4: {0}", myBV(mySect4))

      ' Sets each section to a new value and displays the value of the BitVector32 at each step.
      Console.WriteLine("Changing the values of each section:")
      Console.WriteLine(ControlChars.Tab + "Initial:    " + ControlChars.Tab + "{0}", myBV.ToString())
      myBV(mySect1) = 5
      Console.WriteLine(ControlChars.Tab + "mySect1 = 5:" + ControlChars.Tab + "{0}", myBV.ToString())
      myBV(mySect2) = 3
      Console.WriteLine(ControlChars.Tab + "mySect2 = 3:" + ControlChars.Tab + "{0}", myBV.ToString())
      myBV(mySect3) = 1
      Console.WriteLine(ControlChars.Tab + "mySect3 = 1:" + ControlChars.Tab + "{0}", myBV.ToString())
      myBV(mySect4) = 9
      Console.WriteLine(ControlChars.Tab + "mySect4 = 9:" + ControlChars.Tab + "{0}", myBV.ToString())

      ' Displays the values of the sections.
      Console.WriteLine("New values:")
      Console.WriteLine(ControlChars.Tab + "mySect1: {0}", myBV(mySect1))
      Console.WriteLine(ControlChars.Tab + "mySect2: {0}", myBV(mySect2))
      Console.WriteLine(ControlChars.Tab + "mySect3: {0}", myBV(mySect3))
      Console.WriteLine(ControlChars.Tab + "mySect4: {0}", myBV(mySect4))

   End Sub 'Main 

End Class 'SamplesBitVector32


' This code produces the following output.
'
' Initial values:
'        mySect1: 0
'        mySect2: 0
'        mySect3: 0
'        mySect4: 0
' Changing the values of each section:
'        Initial:        BitVector32{00000000000000000000000000000000}
'        mySect1 = 5:    BitVector32{00000000000000000000000000000101}
'        mySect2 = 3:    BitVector32{00000000000000000000000000011101}
'        mySect3 = 1:    BitVector32{00000000000000000000000000111101}
'        mySect4 = 9:    BitVector32{00000000000000000000001001111101}
' New values:
'        mySect1: 5
'        mySect2: 3
'        mySect3: 1
'        mySect4: 9

using System;
using System.Collections.Specialized;


public class SamplesBitVector32  {

   public static void Main()  {

      // Creates and initializes a BitVector32.
      BitVector32 myBV = new BitVector32( 0 );

      // Creates four sections in the BitVector32 with maximum values 6, 3, 1, and 15.
      // mySect3, which uses exactly one bit, can also be used as a bit flag.
      BitVector32.Section mySect1 = BitVector32.CreateSection( 6 );
      BitVector32.Section mySect2 = BitVector32.CreateSection( 3, mySect1 );
      BitVector32.Section mySect3 = BitVector32.CreateSection( 1, mySect2 );
      BitVector32.Section mySect4 = BitVector32.CreateSection( 15, mySect3 );

      // Displays the values of the sections.
      Console.WriteLine( "Initial values:" );
      Console.WriteLine( "\tmySect1: {0}", myBV[mySect1] );
      Console.WriteLine( "\tmySect2: {0}", myBV[mySect2] );
      Console.WriteLine( "\tmySect3: {0}", myBV[mySect3] );
      Console.WriteLine( "\tmySect4: {0}", myBV[mySect4] );

      // Sets each section to a new value and displays the value of the BitVector32 at each step.
      Console.WriteLine( "Changing the values of each section:" );
      Console.WriteLine( "\tInitial:    \t{0}", myBV.ToString() );
      myBV[mySect1] = 5;
      Console.WriteLine( "\tmySect1 = 5:\t{0}", myBV.ToString() );
      myBV[mySect2] = 3;
      Console.WriteLine( "\tmySect2 = 3:\t{0}", myBV.ToString() );
      myBV[mySect3] = 1;
      Console.WriteLine( "\tmySect3 = 1:\t{0}", myBV.ToString() );
      myBV[mySect4] = 9;
      Console.WriteLine( "\tmySect4 = 9:\t{0}", myBV.ToString() );

      // Displays the values of the sections.
      Console.WriteLine( "New values:" );
      Console.WriteLine( "\tmySect1: {0}", myBV[mySect1] );
      Console.WriteLine( "\tmySect2: {0}", myBV[mySect2] );
      Console.WriteLine( "\tmySect3: {0}", myBV[mySect3] );
      Console.WriteLine( "\tmySect4: {0}", myBV[mySect4] );

   }

}

/*
This code produces the following output.

Initial values:
        mySect1: 0
        mySect2: 0
        mySect3: 0
        mySect4: 0
Changing the values of each section:
        Initial:        BitVector32{00000000000000000000000000000000}
        mySect1 = 5:    BitVector32{00000000000000000000000000000101}
        mySect2 = 3:    BitVector32{00000000000000000000000000011101}
        mySect3 = 1:    BitVector32{00000000000000000000000000111101}
        mySect4 = 9:    BitVector32{00000000000000000000001001111101}
New values:
        mySect1: 5
        mySect2: 3
        mySect3: 1
        mySect4: 9

*/

Visual C++

#using <system.dll>

using namespace System;
using namespace System::Collections::Specialized;

int main()
{
   // Creates and initializes a BitVector32.
   BitVector32 myBV(0);

   // Creates four sections in the BitVector32 with maximum values 6, 3, 1, and 15.
   // mySect3, which uses exactly one bit, can also be used as a bit flag.
   BitVector32::Section mySect1 = BitVector32::CreateSection( 6 );
   BitVector32::Section mySect2 = BitVector32::CreateSection( 3, mySect1 );
   BitVector32::Section mySect3 = BitVector32::CreateSection( 1, mySect2 );
   BitVector32::Section mySect4 = BitVector32::CreateSection( 15, mySect3 );

   // Displays the values of the sections.
   Console::WriteLine( "Initial values:" );
   Console::WriteLine( "\tmySect1: {0}", myBV[ mySect1 ] );
   Console::WriteLine( "\tmySect2: {0}", myBV[ mySect2 ] );
   Console::WriteLine( "\tmySect3: {0}", myBV[ mySect3 ] );
   Console::WriteLine( "\tmySect4: {0}", myBV[ mySect4 ] );

   // Sets each section to a new value and displays the value of the BitVector32 at each step.
   Console::WriteLine( "Changing the values of each section:" );
   Console::WriteLine( "\tInitial:    \t {0}", myBV );
   myBV[ mySect1 ] = 5;
   Console::WriteLine( "\tmySect1 = 5:\t {0}", myBV );
   myBV[ mySect2 ] = 3;
   Console::WriteLine( "\tmySect2 = 3:\t {0}", myBV );
   myBV[ mySect3 ] = 1;
   Console::WriteLine( "\tmySect3 = 1:\t {0}", myBV );
   myBV[ mySect4 ] = 9;
   Console::WriteLine( "\tmySect4 = 9:\t {0}", myBV );

   // Displays the values of the sections.
   Console::WriteLine( "New values:" );
   Console::WriteLine( "\tmySect1: {0}", myBV[ mySect1 ] );
   Console::WriteLine( "\tmySect2: {0}", myBV[ mySect2 ] );
   Console::WriteLine( "\tmySect3: {0}", myBV[ mySect3 ] );
   Console::WriteLine( "\tmySect4: {0}", myBV[ mySect4 ] );
}

/*
This code produces the following output.

Initial values:
        mySect1: 0
        mySect2: 0
        mySect3: 0
        mySect4: 0
Changing the values of each section:
        Initial:        BitVector32 {00000000000000000000000000000000}
        mySect1 = 5:    BitVector32 {00000000000000000000000000000101}
        mySect2 = 3:    BitVector32 {00000000000000000000000000011101}
        mySect3 = 1:    BitVector32 {00000000000000000000000000111101}
        mySect4 = 9:    BitVector32 {00000000000000000000001001111101}
New values:
        mySect1: 5
        mySect2: 3
        mySect3: 1
        mySect4: 9

*/

Thread Safety

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Platforms

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Version Information

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 3.5, 2.0, 1.0

XNA Framework

Supported in: 3.0, 2.0, 1.0

Reference

BitVector32 Members

System.Collections.Specialized Namespace

BitArray