RFC 1014 (rfc1014) - Page 2 of 20

XDR: External Data Representation standard

RFC 1014              External Data Representation             June 1987


   residual zero bytes, r, to make the total byte count a multiple of 4.

   We include the familiar graphic box notation for illustration and
   comparison.  In most illustrations, each box (delimited by a plus
   sign at the 4 corners and vertical bars and dashes) depicts a byte.
   Ellipses (...) between boxes show zero or more additional bytes where
   required.

        +--------+--------+...+--------+--------+...+--------+
        | byte 0 | byte 1 |...|byte n-1|    0   |...|    0   |   BLOCK
        +--------+--------+...+--------+--------+...+--------+
        |<-----------n bytes---------->|<------r bytes------>|
        |<-----------n+r (where (n+r) mod 4 = 0)>----------->|

3. XDR DATA TYPES

   Each of the sections that follow describes a data type defined in the
   XDR standard, shows how it is declared in the language, and includes
   a graphic illustration of its encoding.

   For each data type in the language we show a general paradigm
   declaration.  Note that angle brackets (< and >) denote
   variablelength sequences of data and square brackets ([ and ]) denote
   fixed-length sequences of data.  "n", "m" and "r" denote integers.
   For the full language specification and more formal definitions of
   terms such as "identifier" and "declaration", refer to section 5:
   "The XDR Language Specification".

   For some data types, more specific examples are included.  A more
   extensive example of a data description is in section 6:  "An Example
   of an XDR Data Description".

3.1 Integer

   An XDR signed integer is a 32-bit datum that encodes an integer in
   the range [-2147483648,2147483647].  The integer is represented in
   two's complement notation.  The most and least significant bytes are
   0 and 3, respectively.  Integers are declared as follows:

         int identifier;

           (MSB)                   (LSB)
         +-------+-------+-------+-------+
         |byte 0 |byte 1 |byte 2 |byte 3 |                      INTEGER
         +-------+-------+-------+-------+
         <------------32 bits------------>





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