rotateLeft() - Left Rotating All Bits in a Byte Array

This section provides a tutorial example on how to perform a left rotation of all bits in a byte array - rotateLeft().

If you are trying to implement DES (Data Encryption Standard) encryption algorithm, you will need to rotate bit values in bit strings. With the getBit() and setBit() methods defined above, rotating a bit string stored in a byte array becomes easy to do. Here my rotateLeft() method.

   private static byte[] rotateLeft(byte[] in, int len, int step) {
      int numOfBytes = (len-1)/8 + 1;
      byte[] out = new byte[numOfBytes];
      for (int i=0; i<len; i++) {
         int val = getBit(in,(i+step)%len);
         setBit(out,i,val);
      }
      return out;
   }

Explanations:

Last update: 2014.

Table of Contents

 About This Book

 Installing JDK 1.8 on Windows

 Execution Process, Entry Point, Input and Output

 Primitive Data Types and Literals

 Bits, Bytes, Bitwise and Shift Operations

Managing Bit Strings in Byte Arrays

 setBit() - Storing a Bit into a Byte Array

 getBit() - Retrieving a Bit from a Byte Array

rotateLeft() - Left Rotating All Bits in a Byte Array

 bitStringTest.java - Testing Program

 Reference Data Types and Variables

 StringBuffer - The String Buffer Class

 System Properties and Runtime Object Methods

 Generic Classes and Parameterized Types

 Generic Methods and Type Inference

 Lambda Expressions and Method References

 Execution Threads and Multi-Threading Java Programs

 ThreadGroup Class and "system" ThreadGroup Tree

 Synchronization Technique and Synchronized Code Blocks

 Deadlock Condition Example Programs

 Garbage Collection and the gc() Method

 Outdated Tutorials

 References

 PDF Printing Version