Moved core extensions to Net::BER. Documented.

lib/net/ber/core_ext/array.rb

@@ -0,0 +1,79 @@
+module Net::BER::Extensions::Array
+  ##
+  # Converts an Array to a BER sequence. All values in the Array are
+  # expected to be in BER format prior to calling this method.
+  def to_ber(id = 0)
+    # The universal sequence tag 0x30 is composed of the base tag value
+    # (0x10) and the constructed flag (0x20).
+    to_ber_seq_internal(0x30 + id)
+  end
+  alias_method :to_ber_sequence, :to_ber
+
+  ##
+  # Converts an Array to a BER set. All values in the Array are expected to
+  # be in BER format prior to calling this method.
+  def to_ber_set(id = 0)
+    # The universal set tag 0x31 is composed of the base tag value (0x11)
+    # and the constructed flag (0x20).
+    to_ber_seq_internal(0x31 + id)
+  end
+
+  ##
+  # Converts an Array to an application-specific sequence, assigned a tag
+  # value that is meaningful to the particular protocol being used. All
+  # values in the Array are expected to be in BER format pr prior to calling
+  # this method.
+  #--
+  # Implementor's note 20100320(AZ): RFC 4511 (the LDAPv3 protocol) as well
+  # as earlier RFCs 1777 and 2559 seem to indicate that LDAP only has
+  # application constructed sequences (0x60). However, ldapsearch sends some
+  # context-specific constructed sequences (0xA0); other clients may do the
+  # same. This behaviour appears to violate the RFCs. In real-world
+  # practice, we may need to change calls of #to_ber_appsequence to
+  # #to_ber_contextspecific for full LDAP server compatibility.
+  #
+  # This note probably belongs elsewhere.
+  #++
+  def to_ber_appsequence(id = 0)
+    # The application sequence tag always starts from the application flag
+    # (0x40) and the constructed flag (0x20).
+    to_ber_seq_internal(0x60 + id)
+  end
+
+  ##
+  # Converts an Array to a context-specific sequence, assigned a tag value
+  # that is meaningful to the particular context of the particular protocol
+  # being used. All values in the Array are expected to be in BER format
+  # prior to calling this method.
+  def to_ber_contextspecific(id = 0)
+    # The application sequence tag always starts from the context flag
+    # (0x80) and the constructed flag (0x20).
+    to_ber_seq_internal(0xa0 + id)
+  end
+
+  ##
+  # The internal sequence packing routine. All values in the Array are
+  # expected to be in BER format prior to calling this method.
+  def to_ber_seq_internal(code)
+    s = self.join
+    [code].pack('C') + s.length.to_ber_length_encoding + s
+  end
+  private :to_ber_seq_internal
+
+  ##
+  # SNMP Object Identifiers (OID) are special arrays
+  #--
+  # 20100320 AZ: I do not think that this method should be in BER, since
+  # this appears to be SNMP-specific. This should probably be subsumed by a
+  # proper SNMP OID object.
+  #++
+  def to_ber_oid
+    ary = self.dup
+    first = ary.shift
+    raise Net::BER::BerError, "Invalid OID" unless [0, 1, 2].include?(first)
+    first = first * 40 + ary.shift
+    ary.unshift first
+    oid = ary.pack("w*")
+    [6, oid.length].pack("CC") + oid
+  end
+end