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Diffstat (limited to 'src/main/model/asn1/Null.java')
-rw-r--r-- | src/main/model/asn1/Null.java | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/src/main/model/asn1/Null.java b/src/main/model/asn1/Null.java new file mode 100644 index 0000000..019db85 --- /dev/null +++ b/src/main/model/asn1/Null.java @@ -0,0 +1,45 @@ +package model.asn1; + +import model.asn1.exceptions.ParseException; +import model.asn1.parsing.BytesReader; + +/** + * Represents the ASN.1 NULL type. It always has zero length. With the default assigned tag, it always encodes + * into 0x05 0x00. + */ +public class Null extends ASN1Object { + /** + * The X.680 universal class tag assignment. + */ + public static final Tag TAG = new Tag(TagClass.UNIVERSAL, false, 0x5); + + /** + * EFFECTS: Initiate the NULL with the given tag and an optional context-specific tag number for explicit + * encoding. For more information, consult {@link ASN1Object}. NULL does not take any other arguments. + * REQUIRES: Consult {@link ASN1Object}. + */ + public Null(Tag tag, Tag parentTag) { + super(tag, parentTag); + } + + /** + * EFFECTS: Parse input bytes. For more information on tags parsing, consult {@link ASN1Object}. + * Throws {@link ParseException} if the input data is invalid: + * - The length is not 0 + * - Other cases as denoted in {@link ASN1Object} + */ + public Null(BytesReader encoded, boolean hasParentTag) throws ParseException { + super(encoded, hasParentTag); + if (getLength() != 0) { + throw new ParseException("NULL must have zero length!"); + } + } + + /** + * EFFECTS: Always produce an empty array. + */ + @Override + public Byte[] encodeValueDER() { + return new Byte[0]; + } +} |