Package com.google.zxing.common

Class BitSource

java.lang.Object
com.google.zxing.common.BitSource
public final class BitSource extends Object

This provides an easy abstraction to read bits at a time from a sequence of bytes, where the number of bits read is not often a multiple of 8.

This class is thread-safe but not reentrant -- unless the caller modifies the bytes array it passed in, in which case all bets are off.

Author:
Sean Owen

  • Constructor Details

    • BitSource

      public BitSource(byte[] bytes)
      Parameters:
      bytes - bytes from which this will read bits. Bits will be read from the first byte first. Bits are read within a byte from most-significant to least-significant bit.

  • Method Details

    • getBitOffset

      public int getBitOffset()
      Returns:
      index of next bit in current byte which would be read by the next call to readBits(int).

    • getByteOffset

      public int getByteOffset()
      Returns:
      index of next byte in input byte array which would be read by the next call to readBits(int).

    • readBits

      public int readBits(int numBits)
      Parameters:
      numBits - number of bits to read
      Returns:
      int representing the bits read. The bits will appear as the least-significant bits of the int
      Throws:
      IllegalArgumentException - if numBits isn't in [1,32] or more than is available

    • available

      public int available()
      Returns:
      number of bits that can be read successfully