Package com.google.zxing.common

Class BitArray

java.lang.Object
com.google.zxing.common.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.

Author:
Sean Owen

  • Constructor Details

    • BitArray

      public BitArray()

    • BitArray

      public BitArray(int size)

    • BitArray

      BitArray(int[] bits, int size)

  • Method Details

    • 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

      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:

    • 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 start or the range is not contained in the array

    • 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)

    • xor

      public void xor(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)
      Overrides:
      equals in class Object

    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class Object

    • toString

      public String toString()
      Overrides:
      toString in class Object

    • clone

      public BitArray clone()
      Overrides:
      clone in class Object