Representing Arrays as Streams of Bits

Environment: MFC

I wrote this class when I needed to extract separate bits of data from an array, one by one. After some calculations, I found I needed to put modified bits in another array of data. I think this class may be useful, so here it is.

This class operates with data located in the CByteArray object. So, the common steps to use CBitStream are:

  1. Declare a CByteArray object.
  2. Declare a CBitStream object, supplying a reference to the newly created CByteArray object to the constructor of the first one.
  3. Enjoy. :)

To set/get the next bit, you can use either overloaded shifting operators or SetBit()/GetBit() functions. Also, you can navigate inside the array of data. You can set a "pointer" to any bit inside your array.

Also, you can choose the order in which bits of every byte will be processed. The default is a "left-to-right" order. In this order, the bits affected are: 7th, 6th, 5th, 4th, 3rd, 2nd, 1st, and then the 0 bit. You can define the RIGHTTOLEFTFILL identifier to change the order to right-to-left, in which bits are accessed: 0, 1st, 2nd, 3rd, 4th, 5th, 6th, and then 7th. I prefer the left-to-right order because it is easier to understand. Look to the picture below. a) is the left-to-right order (default) and b) is the right-to-left order.

CByteArray array;
CBitStream stream(array);

stream<<0<<1<<0<<0<<1<<0<<0<<1;
// The first byte now consists of 01001001 bits, so it equals 73
// (0x49). It's true when you are using the left-to-right order.
stream.SetBit(0);
stream.SetBit(1);
stream.SetBit(0);
stream.SetBit(0);
stream.SetBit(1);
stream.SetBit(0);
stream.SetBit(0);
stream.SetBit(1);
// The second byte is now the same as the first.

Downloads

Download demo project - 10 Kb
Download source - 3 Kb


Comments

  • Good

    Posted by Legacy on 04/01/2003 12:00am

    Originally posted by: 트론의유령

    Godd! 재밌어요

    Reply
Leave a Comment
  • Your email address will not be published. All fields are required.

Top White Papers and Webcasts

  • Cloud computing isn't new, but it's still a hot topic in technology circles. Moving to the cloud has done great things for many businesses. When it comes to handling a basic business necessity, cloud computing has brought many improvements to overall business continuity. Using the cloud for DR makes a lot of sense for many, but it's not exactly the most simple concept. Read this eBook to find answers to all the key questions IT professionals have about cloud-based disaster recovery, and helpful info around the …

  • Intelligent N+X Redundancy, Placement Affinities, & Future Proofing in the Virtualized Data Center Virtualization brought about the ability to simplify business continuity management in IT. Workload portability and data replication capabilities mean that physical infrastructure failures no longer need impact application services, and they can rapidly be recovered even in the event of complete site failure. However, Enterprises and Service Providers face new challenges ensuring they have enough compute …

Most Popular Programming Stories

More for Developers

RSS Feeds

Thanks for your registration, follow us on our social networks to keep up-to-date