OIDs are represented as a series of hierarchical tokens, each of * which is usually represented as a single, unsigned integer. The * hierarchy works so that later tokens are considered within the group * of earlier tokens. Thus, the OID for the Serpent block cipher, * 1.3.6.1.4.1.11591.13.2, is maintained by the GNU project, whose OID * is 1.3.6.1.4.1.11591 (which is, in turn, part of bigger, more general * bodies; the topmost, 1, stands for the OIDs assigned by the * International Standards Organization, ISO). * *
OIDs can be represented in a variety of ways, including the * dotted-decimal form we use here. * *
OIDs may be relative, in which case the first two elements of the * OID are omitted. * * @author Casey Marshall (csm@gnu.org) */ public class OID implements Cloneable, Comparable, java.io.Serializable { // Fields. // ------------------------------------------------------------------------ /* Serial version id for serialization. */ static final long serialVersionUID = 5722492029044597779L; /** * The numeric ID structure. */ private int[] components; /** * The string representation of this OID, in dotted-decimal format. */ private transient String strRep; /** * The DER encoding of this OID. */ private transient byte[] der; /** * Whether or not this OID is relative. */ private boolean relative; // Constructors. // ------------------------------------------------------------------------ /** * Create a new OID from the given byte array. The argument (which can * neither be null nor zero-length) is copied to prevent subsequent * modification. * * @param components The numeric IDs. * @throws IllegalArgumentException If components is null or empty. */ public OID(int[] components) { this(components, false); } /** * Create a new OID from the given byte array. The argument (which can * neither be null nor zero-length) is copied to prevent subsequent * modification. * * @param components The numeric IDs. * @param relative The relative flag. * @throws IllegalArgumentException If components is null or empty. */ public OID(int[] components, boolean relative) { if (components == null || components.length == 0) throw new IllegalArgumentException(); this.components = (int[]) components.clone(); this.relative = relative; } /** * Create a new OID from the given dotted-decimal representation. * * @param strRep The string representation of the OID. * @throws IllegalArgumentException If the string does not contain at * least one integer. * @throws NumberFormatException If the string does not contain only * numbers and periods ('.'). */ public OID(String strRep) { this(strRep, false); } /** * Create a new OID from the given dotted-decimal representation. * * @param strRep The string representation of the OID. * @param relative The relative flag. * @throws IllegalArgumentException If the string does not contain at * least one integer. * @throws NumberFormatException If the string does not contain only * numbers and periods ('.'). */ public OID(String strRep, boolean relative) { this.relative = relative; this.strRep = strRep; components = fromString(strRep); } /** * Construct a new OID from the DER bytes in an input stream. This method * does not read the tag or the length field from the input stream, so * the caller must supply the number of octets in this OID's encoded * form. * * @param derIn The DER input stream. * @param len The number of bytes in the encoded form. * @throws IOException If an error occurs reading the OID. */ public OID(InputStream derIn, int len) throws IOException { this(derIn, len, false); } /** * Construct a new OID from the DER bytes in an input stream. This method * does not read the tag or the length field from the input stream, so * the caller must supply the number of octets in this OID's encoded * form. * * @param derIn The DER input stream. * @param len The number of bytes in the encoded form. * @param relative The relative flag. * @throws IOException If an error occurs reading the OID. */ public OID(InputStream derIn, int len, boolean relative) throws IOException { der = new byte[len]; derIn.read(der); this.relative = relative; try { components = fromDER(der, relative); } catch (ArrayIndexOutOfBoundsException aioobe) { aioobe.printStackTrace(); throw aioobe; } } /** * Construct a new OID from the given DER bytes. * * @param encoded The DER encoded OID. * @throws IOException If an error occurs reading the OID. */ public OID(byte[] encoded) throws IOException { this(encoded, false); } /** * Construct a new OID from the given DER bytes. * * @param encoded The encoded relative OID. * @param relative The relative flag. */ public OID(byte[] encoded, boolean relative) throws IOException { der = (byte[]) encoded.clone(); this.relative = relative; try { components = fromDER(der, relative); } catch (ArrayIndexOutOfBoundsException aioobe) { aioobe.printStackTrace(); throw aioobe; } } // Instance methods. // ------------------------------------------------------------------------ /** * Return the numeric IDs of this OID. The value returned is copied to * prevent modification. * * @return The IDs in a new integer array. */ public int[] getIDs() { return (int[]) components.clone(); } /** * Get the DER encoding of this OID, minus the tag and length fields. * * @return The DER bytes. */ public byte[] getDER() { if (der == null) { ByteArrayOutputStream bout = new ByteArrayOutputStream(); int i = 0; if (!relative) { int b = components[i++] * 40 + (components.length > 1 ? components[i++] : 0); encodeSubID(bout, b); } for ( ; i < components.length; i++) encodeSubID(bout, components[i]); der = bout.toByteArray(); } return (byte[]) der.clone(); } /** * Get the parent OID of this OID. That is, if this OID is "1.2.3.4", * then the parent OID will be "1.2.3". If this OID is a top-level * OID, this method returns null. * * @return The parent OID, or null. */ public OID getParent() { if (components.length == 1) return null; int[] parent = new int[components.length - 1]; System.arraycopy(components, 0, parent, 0, parent.length); return new OID(parent); } public OID getChild(int id) { int[] child = new int[components.length + 1]; System.arraycopy(components, 0, child, 0, components.length); child[child.length - 1] = id; return new OID(child); } /** * Get the root OID of this OID. That is, the first two components. * * @return The root OID. */ public OID getRoot() { if (components.length <= 2) return this; int[] root = new int[2]; root[0] = components[0]; root[1] = components[1]; return new OID(root); } public boolean isRelative() { return relative; } /** * Returns a copy of this OID. * * @return The copy. */ public Object clone() { try { return super.clone(); } catch (CloneNotSupportedException cnse) { InternalError ie = new InternalError(); ie.initCause(cnse); throw ie; } } /* Nice idea, but possibly too expensive for whatever benefit it * provides. public String getShortName() { return OIDTable.getShortName(this); } public String getLongName() { return OIDTable.getLongName(this); } */ /** * Returns the value of this OID in dotted-decimal format. * * @return The string representation. */ public String toString() { if (strRep != null) return strRep; else { CPStringBuilder buf = new CPStringBuilder(); for (int i = 0; i < components.length; i++) { buf.append((long) components[i] & 0xFFFFFFFFL); if (i < components.length - 1) buf.append('.'); } return (strRep = buf.toString()); } } /** * Computes a hash code for this OID. * * @return The hash code. */ public int hashCode() { int ret = 0; for (int i = 0; i < components.length; i++) ret += components[i] << (i & 31); return ret; } /** * Tests whether or not this OID equals another. * * @return Whether or not this OID equals the other. */ public boolean equals(Object o) { if (!(o instanceof OID)) return false; return java.util.Arrays.equals(components, ((OID) o).components); } /** * Compares this OID to another. The comparison is essentially * lexicographic, where the two OIDs are compared until their * first difference, then that difference is returned. If one OID is * shorter, but all elements equal between the two for the shorter * length, then the shorter OID is lesser than the longer. * * @param o The object to compare. * @return An integer less than, equal to, or greater than zero if * this object is less than, equal to, or greater than the * argument. * @throws ClassCastException If o is not an OID. */ public int compareTo(Object o) { if (equals(o)) return 0; int[] components2 = ((OID) o).components; int len = Math.min(components.length, components2.length); for (int i = 0; i < len; i++) { if (components[i] != components2[i]) return (components[i] < components2[i]) ? -1 : 1; } if (components.length == components2.length) return 0; return (components.length < components2.length) ? -1 : 1; } // Own methods. // ------------------------------------------------------------------------ private static int[] fromDER(byte[] der, boolean relative) throws DEREncodingException { // cannot be longer than this. int[] components = new int[der.length + 1]; int count = 0; int i = 0; if (!relative && i < der.length) { // Non-relative OIDs have the first two arcs coded as: // // i = first_arc * 40 + second_arc; // int j = (der[i] & 0xFF); components[count++] = j / 40; components[count++] = j % 40; i++; } while (i < der.length) { int j = 0; do { j = der[i++] & 0xFF; components[count] <<= 7; components[count] |= j & 0x7F; if (i >= der.length && (j & 0x80) != 0) throw new DEREncodingException("malformed OID"); } while ((j & 0x80) != 0); count++; } if (count == components.length) return components; int[] ret = new int[count]; System.arraycopy(components, 0, ret, 0, count); return ret; } private static int[] fromString(String strRep) throws NumberFormatException { if (strRep.startsWith("OID.") || strRep.startsWith("oid.")) strRep = strRep.substring(4); StringTokenizer tok = new StringTokenizer(strRep, "."); if (tok.countTokens() == 0) throw new IllegalArgumentException(); int[] components = new int[tok.countTokens()]; int i = 0; while (tok.hasMoreTokens()) { components[i++] = Integer.parseInt(tok.nextToken()); } return components; } private static void encodeSubID(ByteArrayOutputStream out, int id) { if (id < 128) { out.write(id); } else if (id < 16384) { out.write((id >>> 7) | 0x80); out.write(id & 0x7F); } else if (id < 2097152) { out.write((id >>> 14) | 0x80); out.write(((id >>> 7) | 0x80) & 0xFF); out.write(id & 0x7F); } else if (id < 268435456) { out.write( (id >>> 21) | 0x80); out.write(((id >>> 14) | 0x80) & 0xFF); out.write(((id >>> 7) | 0x80) & 0xFF); out.write(id & 0x7F); } } }