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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 | |
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static Form |
CONSTRUCTED
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static Form |
PRIMITIVE
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Constructor Summary | |
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ASN1Header(java.io.InputStream istream)
Gets info about the next item in the DER stream, consuming the identifier and length octets. |
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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 | |
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byte[] |
encode()
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void |
encode(java.io.OutputStream ostream)
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long |
getContentLength()
Returns -1 for indefinite length encoding. |
Form |
getForm()
Returns the Form, PRIMITIVE or CONSTRUCTED. |
Tag |
getTag()
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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()
Returns true if this is a BER end-of-contents marker. |
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. |
Methods inherited from class java.lang.Object |
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Field Detail |
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PRIMITIVE
public static final Form PRIMITIVE
CONSTRUCTED
public static final Form CONSTRUCTED
Constructor Detail |
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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.
- Throws:
InvalidBERException
java.io.IOException
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:
contentLength
- Must be >=0. Although indefinite length decoding is supported, indefinite length encoding is not.
Method Detail |
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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.
getTag
public Tag getTag()
getContentLength
public long getContentLength()
- Returns -1 for indefinite length encoding.
getForm
public Form getForm()
- Returns the Form, PRIMITIVE or CONSTRUCTED.
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.
- Throws:
java.io.IOException
- If the input stream does not support look ahead.InvalidBERException
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.
validate
public void validate(Tag expectedTag, Form expectedForm) throws InvalidBERException
- Verifies that this header has the given tag and 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.
- 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.
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