Package com.webcodepro.shrinkit.io

Class BitInputStream

java.lang.Object
java.io.InputStream
com.webcodepro.shrinkit.io.BitInputStream
All Implemented Interfaces:
BitConstants, Closeable, AutoCloseable
public class BitInputStream extends InputStream implements BitConstants
The BitInputStream allows varying bit sizes to be pulled out of the wrapped InputStream. This is useful for LZW type compression algorithms where 9-12 bit codes are used instead of the 8-bit byte.

Warning: The read(byte[]) and read(byte[], int, int) methods of InputStream will not work appropriately with any bit size > 8 bits.

  • Constructor Details

    • BitInputStream

      public BitInputStream(InputStream is, int startingNumberOfBits)
      Create a BitInputStream wrapping the given InputStream and reading the number of bits specified.

  • Method Details

    • setRequestedNumberOfBits

      public void setRequestedNumberOfBits(int numberOfBits)
      Set the number of bits to be read with each call to read().

    • increaseRequestedNumberOfBits

      public void increaseRequestedNumberOfBits()
      Increase the requested number of bits by one. This is the general usage and prevents client from needing to track the requested number of bits or from making various method calls.

    • getBitMask

      public int getBitMask()
      Answer with the current bit mask for the current bit size.

    • read

      public int read() throws IOException
      Read a number of bits off of the wrapped InputStream.
      Specified by:
      read in class InputStream
      Throws:
      IOException

    • clearRemainingBitsOfData

      public void clearRemainingBitsOfData()
      When shifting from buffer to buffer, the input stream also should be reset. This allows the "left over" bits to be cleared.