com.google.zxing.common

Class BitArray

  • All Implemented Interfaces:
    Cloneable 

    public final class BitArray
extends Object
implements Cloneable

    A simple, fast array of bits, represented compactly by an array of ints internally.

    • Constructor Summary

      Constructors

      Constructor and Description
      BitArray()
       
      BitArray(int size)
       

    • Method Summary

      Modifier and Type Method and Description
      void appendBit(boolean bit)
       
      void appendBitArray(BitArray other)
       
      void appendBits(int value, int numBits)
      Appends the least-significant bits, from value, in order from most-significant to least-significant.
      void clear()
      Clears all bits (sets to false).
      BitArray clone()
       
      boolean equals(Object o)
       
      void flip(int i)
      Flips bit i.
      boolean get(int i)
       
      int[] getBitArray()
       
      int getNextSet(int from)
       
      int getNextUnset(int from)
       
      int getSize()
       
      int getSizeInBytes()
       
      int hashCode()
       
      boolean isRange(int start, int end, boolean value)
      Efficient method to check if a range of bits is set, or not set.
      void reverse()
      Reverses all bits in the array.
      void set(int i)
      Sets bit i.
      void setBulk(int i, int newBits)
      Sets a block of 32 bits, starting at bit i.
      void setRange(int start, int end)
      Sets a range of bits.
      void toBytes(int bitOffset, byte[] array, int offset, int numBytes)
       
      String toString()
       
      void xor(BitArray other)
       

    • Constructor Detail

      • BitArray

        public BitArray()

      • BitArray

        public BitArray(int size)

    • Method Detail

      • getSize

        public int getSize()

      • getSizeInBytes

        public int getSizeInBytes()

      • get

        public boolean get(int i)
        Parameters:
        i - bit to get
        Returns:
        true iff bit i is set

      • set

        public void set(int i)
        Sets bit i.
        Parameters:
        i - bit to set

      • flip

        public void flip(int i)
        Flips bit i.
        Parameters:
        i - bit to set

      • getNextSet

        public int getNextSet(int from)
        Parameters:
        from - first bit to check
        Returns:
        index of first bit that is set, starting from the given index, or size if none are set at or beyond this given index
        See Also:
        getNextUnset(int)

      • getNextUnset

        public int getNextUnset(int from)
        Parameters:
        from - index to start looking for unset bit
        Returns:
        index of next unset bit, or size if none are unset until the end
        See Also:
        getNextSet(int)

      • setBulk

        public void setBulk(int i,
                    int newBits)
        Sets a block of 32 bits, starting at bit i.
        Parameters:
        i - first bit to set
        newBits - the new value of the next 32 bits. Note again that the least-significant bit corresponds to bit i, the next-least-significant to i+1, and so on.

      • setRange

        public void setRange(int start,
                     int end)
        Sets a range of bits.
        Parameters:
        start - start of range, inclusive.
        end - end of range, exclusive

      • clear

        public void clear()
        Clears all bits (sets to false).

      • isRange

        public boolean isRange(int start,
                       int end,
                       boolean value)
        Efficient method to check if a range of bits is set, or not set.
        Parameters:
        start - start of range, inclusive.
        end - end of range, exclusive
        value - if true, checks that bits in range are set, otherwise checks that they are not set
        Returns:
        true iff all bits are set or not set in range, according to value argument
        Throws:
        IllegalArgumentException - if end is less than or equal to start

      • appendBit

        public void appendBit(boolean bit)

      • appendBits

        public void appendBits(int value,
                       int numBits)
        Appends the least-significant bits, from value, in order from most-significant to least-significant. For example, appending 6 bits from 0x000001E will append the bits 0, 1, 1, 1, 1, 0 in that order.
        Parameters:
        value - int containing bits to append
        numBits - bits from value to append

      • appendBitArray

        public void appendBitArray(BitArray other)

      • toBytes

        public void toBytes(int bitOffset,
                    byte[] array,
                    int offset,
                    int numBytes)
        Parameters:
        bitOffset - first bit to start writing
        array - array to write into. Bytes are written most-significant byte first. This is the opposite of the internal representation, which is exposed by getBitArray()
        offset - position in array to start writing
        numBytes - how many bytes to write

      • getBitArray

        public int[] getBitArray()
        Returns:
        underlying array of ints. The first element holds the first 32 bits, and the least significant bit is bit 0.

      • reverse

        public void reverse()
        Reverses all bits in the array.

      • equals

        public boolean equals(Object o)

      • hashCode

        public int hashCode()

      • toString

        public String toString()