Package org.mozilla.jss.asn1
Class ASN1Header
- java.lang.Object
-
- org.mozilla.jss.asn1.ASN1Header
-
public class ASN1Header extends java.lang.Object
The portion of a BER encoding that precedes the contents octets. Consists of the tag, form, and length octets.
-
-
Field Summary
Fields Modifier and Type Field Description static Form
CONSTRUCTED
static Form
PRIMITIVE
-
Constructor Summary
Constructors Constructor Description ASN1Header(java.io.InputStream istream)
Gets info about the next item in the DER stream, consuming the identifier and length octets.ASN1Header(Tag tag, Form form, long contentLength)
This constructor is to be called when we are constructing an ASN1Value rather than decoding it.
-
Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description byte[]
encode()
void
encode(java.io.OutputStream ostream)
long
getContentLength()
Returns -1 for indefinite length encoding.Form
getForm()
Returns the Form, PRIMITIVE or CONSTRUCTED.Tag
getTag()
long
getTotalLength()
Returns the length of the header plus the length of the contents; the total length of the DER encoding of an ASN1 value.boolean
isEOC()
static ASN1Header
lookAhead(java.io.InputStream derStream)
Returns information about the next item in the stream, but does not consume any octets.static byte[]
unsignedBigIntToByteArray(java.math.BigInteger bi)
Converts an unsigned BigInteger to a minimal-length byte array.void
validate(Tag expectedTag)
Verifies that this head has the given tag.void
validate(Tag expectedTag, Form expectedForm)
Verifies that this header has the given tag and form.
-
-
-
Constructor Detail
-
ASN1Header
public ASN1Header(java.io.InputStream istream) throws InvalidBERException, java.io.IOException
Gets info about the next item in the DER stream, consuming the identifier and length octets.- Parameters:
istream
- Input stream.- Throws:
InvalidBERException
- If there is an invalid BER encoding.java.io.IOException
- If other error occurred.
-
ASN1Header
public ASN1Header(Tag tag, Form form, long contentLength)
This constructor is to be called when we are constructing an ASN1Value rather than decoding it.- Parameters:
tag
- Tag.form
- Form.contentLength
- Must be ≥0. Although indefinite length decoding is supported, indefinite length encoding is not.
-
-
Method Detail
-
getTotalLength
public long getTotalLength()
Returns the length of the header plus the length of the contents; the total length of the DER encoding of an ASN1 value. Returns -1 if indefinite length encoding was used.- Returns:
- Total length.
-
getTag
public Tag getTag()
-
getContentLength
public long getContentLength()
Returns -1 for indefinite length encoding.- Returns:
- Content length.
-
getForm
public Form getForm()
Returns the Form, PRIMITIVE or CONSTRUCTED.- Returns:
- The form.
-
lookAhead
public static ASN1Header lookAhead(java.io.InputStream derStream) throws java.io.IOException, InvalidBERException
Returns information about the next item in the stream, but does not consume any octets.- Parameters:
derStream
- DER stream.- Returns:
- ASN.1 header.
- Throws:
InvalidBERException
- If there is an invalid BER encoding.java.io.IOException
- If the input stream does not support look ahead.
-
encode
public void encode(java.io.OutputStream ostream) throws java.io.IOException
- Throws:
java.io.IOException
-
encode
public byte[] encode()
-
unsignedBigIntToByteArray
public static byte[] unsignedBigIntToByteArray(java.math.BigInteger bi)
Converts an unsigned BigInteger to a minimal-length byte array. This is necessary because BigInteger.toByteArray() attaches an extra sign bit, which could cause the size of the byte representation to be bumped up by an extra byte.- Parameters:
bi
- Input BigInteger.- Returns:
- Byte array.
-
validate
public void validate(Tag expectedTag, Form expectedForm) throws InvalidBERException
Verifies that this header has the given tag and form.- Parameters:
expectedTag
- Expected tag.expectedForm
- Expected form.- Throws:
InvalidBERException
- If the header's tag or form differ from those passed in.
-
validate
public void validate(Tag expectedTag) throws InvalidBERException
Verifies that this head has the given tag.- Parameters:
expectedTag
- Expected tag.- Throws:
InvalidBERException
- If the header's tag differs from that passed in.
-
isEOC
public boolean isEOC()
- Returns:
true
if this is a BER end-of-contents marker.
-
-