org.apache.pdfbox.io: public class: NBitInputStream

org.apache.pdfbox.io
public class: NBitInputStream [javadoc | source]

java.lang.Object
   org.apache.pdfbox.io.NBitInputStream

This is an n-bit input stream. This means that you can read chunks of data as any number of bits, not just 8 bits like the regular input stream. Just set the number of bits that you would like to read on each call. The default is 8.

author:

 -  href="mailto:ben@benlitchfield.com">Ben Litchfield

version: $ - Revision: 1.4 $










    







    












    Constructor:
 public NBitInputStream(InputStream is) {
        in = is;
        bitsLeftInCurrentByte = 0;
        bitsInChunk = 8;
}
Constructor.
Parameters:
is -  The input stream to read from.










    Method from org.apache.pdfbox.io.NBitInputStream Summary:

getBitsInChunk,   read,   setBitsInChunk,   unread
Methods from java.lang.Object:

clone,   equals,   finalize,   getClass,   hashCode,   notify,   notifyAll,   toString,   wait,   wait,   wait
Method from org.apache.pdfbox.io.NBitInputStream Detail:
 public int getBitsInChunk() {
        return bitsInChunk;
}
Getter for property bitsToRead.
 public long read() throws IOException {
        long retval = 0;
        for( int i=0; i< bitsInChunk && retval != -1; i++ )
        {
            if( bitsLeftInCurrentByte == 0 )
            {
                currentByte = in.read();
                bitsLeftInCurrentByte = 8;
            }
            if( currentByte == -1 )
            {
                retval = -1;
            }
            else
            {
                retval < < = 1;
                retval |= ((currentByte  > > (bitsLeftInCurrentByte-1))&0x1);
                bitsLeftInCurrentByte--;
            }
        }
        return retval;
}
This will read the next n bits from the stream and return the unsigned
value of  those bits.
 public  void setBitsInChunk(int bitsInChunkValue) {
        bitsInChunk = bitsInChunkValue;
}
Setter for property bitsToRead.
 public  void unread(long data) {
        data < < = bitsLeftInCurrentByte;
        currentByte |= data;
        bitsLeftInCurrentByte += bitsInChunk;
}
This will unread some data.