Class BIT_STRING

  • All Implemented Interfaces:
    ASN1Value

    public class BIT_STRING
    extends java.lang.Object
    implements ASN1Value
    An ASN.1 BIT STRING, which is an ordered sequence of bits. The bits are stored the same way they are encoded in BER: as an array of bytes with 0-7 unused bits at the end.
    • Nested Class Summary

      Nested Classes 
      Modifier and Type Class Description
      static class  BIT_STRING.Template
      A class for decoding a BIT_STRING from its BER encoding.
    • Field Summary

      Fields 
      Modifier and Type Field Description
      static Form FORM  
      static Tag TAG  
    • Constructor Summary

      Constructors 
      Constructor Description
      BIT_STRING​(byte[] bits, int padCount)  
      BIT_STRING​(java.util.BitSet bs, int numBits)
      Constructs a BIT_STRING from a BitSet.
    • Method Summary

      All Methods Static Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      void encode​(java.io.OutputStream ostream)
      Write this value's DER encoding to an output stream using its own base tag.
      void encode​(Tag implicitTag, java.io.OutputStream ostream)
      Write this value's DER encoding to an output stream using an implicit tag.
      byte[] getBits()
      Returns the bits packed into an array of bytes, with padding at the end.
      int getPadCount()
      Returns the number of padding bits at the end of the array.
      boolean getRemoveTrailingZeroes()
      Determines whether the DER-encoding of this bitstring will have its trailing zeroes removed.
      Tag getTag()
      Returns the base tag for this type, not counting any tags that may be imposed on it by its context.
      static BIT_STRING.Template getTemplate()  
      void setRemoveTrailingZeroes​(boolean removeTrailingZeroes)
      Determines whether the DER-encoding of this bitstring will have its trailing zeroes removed.
      java.util.BitSet toBitSet()
      Copies this BIT STRING into a Java BitSet.
      boolean[] toBooleanArray()
      Copies this BIT STRING into a boolean array.
      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
    • Field Detail

      • TAG

        public static final Tag TAG
      • FORM

        public static final Form FORM
    • Constructor Detail

      • BIT_STRING

        public BIT_STRING​(byte[] bits,
                          int padCount)
                   throws java.lang.NumberFormatException
        Parameters:
        bits - The bits packed into an array of bytes, with padding at the end. The array may be empty (but not null), in which case padCount must be zero. The array is referenced, not cloned.
        padCount - The number of padding bits at the end of the array. Must be in the range [0,7].
        Throws:
        java.lang.NumberFormatException - If padCount is not in the range [0,7], or bits is empty and padCount is non-zero.
      • BIT_STRING

        public BIT_STRING​(java.util.BitSet bs,
                          int numBits)
                   throws java.lang.NumberFormatException
        Constructs a BIT_STRING from a BitSet.
        Parameters:
        bs - A BitSet.
        numBits - The number of bits to copy from the BitSet. This is necessary because the size of a BitSet is always padded up to a multiple of 64, but not all of these bits may be significant.
        Throws:
        java.lang.NumberFormatException - If numBits is larger than bs.size() or less than zero.
    • Method Detail

      • getRemoveTrailingZeroes

        public boolean getRemoveTrailingZeroes()
        Determines whether the DER-encoding of this bitstring will have its trailing zeroes removed. Generally, DER requires that trailing zeroes be removed when the bitstring is used to hold flags, but not when it is used to hold binary data (such as a public key). The default is false.
        Returns:
        True if trailing zeroes are to be removed.
      • setRemoveTrailingZeroes

        public void setRemoveTrailingZeroes​(boolean removeTrailingZeroes)
        Determines whether the DER-encoding of this bitstring will have its trailing zeroes removed. Generally, DER requires that trailing zeroes be removed when the bitstring is used to hold flags, but not when it is used to hold binary data (such as a public key). The default is false. If this bit string is used to hold flags, you should set this to true.
        Parameters:
        removeTrailingZeroes - True if trailing zeroes are to be removed.
      • getBits

        public byte[] getBits()
        Returns the bits packed into an array of bytes, with padding at the end. The array may be empty (but not null), in which case padCount must be zero. The array is referenced, not cloned.
        Returns:
        BIT STRING as byte array.
      • toBitSet

        public java.util.BitSet toBitSet()
        Copies this BIT STRING into a Java BitSet. Note that BitSet.size() will not accurately reflect the number of bits in the BIT STRING, because the size of a BitSet is always rounded up to the next multiple of 64. The extra bits will be set to 0.
        Returns:
        BIT STRING as BitSet.
      • toBooleanArray

        public boolean[] toBooleanArray()
        Copies this BIT STRING into a boolean array. Each element of the array represents one bit with true for 1 and false for 0.
        Returns:
        BIT STRING as boolean array.
      • getPadCount

        public int getPadCount()
        Returns the number of padding bits at the end of the array. Must be in the range [0,7].
        Returns:
        Number of padding.
      • getTag

        public Tag getTag()
        Description copied from interface: ASN1Value
        Returns the base tag for this type, not counting any tags that may be imposed on it by its context.
        Specified by:
        getTag in interface ASN1Value
        Returns:
        Base tag.
      • encode

        public void encode​(java.io.OutputStream ostream)
                    throws java.io.IOException
        Description copied from interface: ASN1Value
        Write this value's DER encoding to an output stream using its own base tag.
        Specified by:
        encode in interface ASN1Value
        Parameters:
        ostream - Output stream.
        Throws:
        java.io.IOException - If an error occurred.
      • encode

        public void encode​(Tag implicitTag,
                           java.io.OutputStream ostream)
                    throws java.io.IOException
        Description copied from interface: ASN1Value
        Write this value's DER encoding to an output stream using an implicit tag.
        Specified by:
        encode in interface ASN1Value
        Parameters:
        implicitTag - Implicit tag.
        ostream - Output stream.
        Throws:
        java.io.IOException - If an error occurred.