Class DLGenerator

java.lang.Object
org.bouncycastle.asn1.ASN1Generator
org.bouncycastle.asn1.DLGenerator
Direct Known Subclasses:
DLOctetStringGenerator, DLSequenceGenerator
public abstract class DLGenerator extends ASN1Generator
Base class for stream generators for definite-length structures. Unlike the BER generators, which stream indefinite-length encodings, these write a definite-length header up front from a caller-supplied body length and so can stream DL (and, with suitably canonical contents, DER) encodings of structures too large to hold in memory — body lengths are long, so content larger than a Java array can carry is supported.

The body length passed to a generator is a commitment: the matching number of content octets must subsequently be written. Subclasses verify this on close() and fail with an IOException on a mismatch, since a wrongly-sized body silently corrupts every enclosing length.

  • Field Summary

    Fields inherited from class ASN1Generator

    _out

  • Constructor Summary

    Constructors
    Modifier
    Constructor
    Description
    protected
    DLGenerator(OutputStream out)
     
    protected
    DLGenerator(OutputStream out, int tagNo, boolean isExplicit)
     

  • Method Summary

    Modifier and Type
    Method
    Description
    static long
    getDLEncodingLength(long bodyLength)
    Return the total encoded length of a TLV with a single identifier octet (i.e. a tag number below 31) and bodyLength content octets.
    static int
    getLengthOctetCount(long bodyLength)
    Return the number of octets in the definite-length encoding of bodyLength (the length octets only, excluding the identifier).
    OutputStream
    getRawOutputStream()
    Return the actual stream object encodings are written to.
    protected void
    writeDLHeader(int tag, long bodyLength)
    Write the definite-length header(s) for this generator's structure: the base tag with bodyLength, preceded (for an explicit tag) by a context-specific wrapper whose length covers the complete base TLV.

    Methods inherited from class Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

    • DLGenerator

      protected DLGenerator(OutputStream out)

    • DLGenerator

      protected DLGenerator(OutputStream out, int tagNo, boolean isExplicit)

  • Method Details

    • getRawOutputStream

      public OutputStream getRawOutputStream()
      Description copied from class: ASN1Generator
      Return the actual stream object encodings are written to.
      Specified by:
      getRawOutputStream in class ASN1Generator
      Returns:
      the stream that is directly encoded to.

    • getLengthOctetCount

      public static int getLengthOctetCount(long bodyLength)
      Return the number of octets in the definite-length encoding of bodyLength (the length octets only, excluding the identifier).
      Parameters:
      bodyLength - number of content octets (>= 0)
      Returns:
      1 for the short form, 1 + number of length octets for the long form

    • getDLEncodingLength

      public static long getDLEncodingLength(long bodyLength)
      Return the total encoded length of a TLV with a single identifier octet (i.e. a tag number below 31) and bodyLength content octets.
      Parameters:
      bodyLength - number of content octets (>= 0)

    • writeDLHeader

      protected void writeDLHeader(int tag, long bodyLength) throws IOException
      Write the definite-length header(s) for this generator's structure: the base tag with bodyLength, preceded (for an explicit tag) by a context-specific wrapper whose length covers the complete base TLV. Tag numbers of 31 and above are supported for the context-specific wrapper of an implicitly tagged structure, but not for an explicit one (the wrapper length arithmetic assumes a single identifier octet).
      Throws:
      IOException