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NAME

       ber_alloc_t,    ber_flush,    ber_flush2,    ber_printf,   ber_put_int,
       ber_put_enum,    ber_put_ostring,     ber_put_string,     ber_put_null,
       ber_put_boolean,   ber_put_bitstring,   ber_start_seq,   ber_start_set,
       ber_put_seq, ber_put_set -  OpenLDAP  LBER  simplified  Basic  Encoding
       Rules library routines for encoding

LIBRARY

       OpenLDAP LBER (liblber, -llber)

SYNOPSIS

       #include <lber.h>

       BerElement *ber_alloc_t(int options);

       int ber_flush(Sockbuf *sb, BerElement *ber, int freeit);

       int ber_flush2(Sockbuf *sb, BerElement *ber, int freeit);

       int ber_printf(BerElement *ber, const char *fmt, ...);

       int ber_put_int(BerElement *ber, ber_int_t num, ber_tag_t tag);

       int ber_put_enum(BerElement *ber, ber_int_t num, ber_tag_t tag);

       int  ber_put_ostring(BerElement  *ber,  const char *str, ber_len_t len,
       ber_tag_t tag);

       int ber_put_string(BerElement *ber, const char *str, ber_tag_t tag);

       int ber_put_null(BerElement *ber, ber_tag_t tag);

       int ber_put_boolean(BerElement *ber, ber_int_t bool, ber_tag_t tag);

       int ber_put_bitstring(BerElement *ber, const char *str, ber_len_t blen,
       ber_tag_t tag);

       int ber_start_seq(BerElement *ber, ber_tag_t tag);

       int ber_start_set(BerElement *ber, ber_tag_t tag);

       int ber_put_seq(BerElement *ber);

       int ber_put_set(BerElement *ber);

DESCRIPTION

       These   routines   provide  a  subroutine  interface  to  a  simplified
       implementation of the Basic Encoding Rules of ASN.1.   The  version  of
       BER  these  routines  support is the one defined for the LDAP protocol.
       The encoding rules are the same as BER, except that only definite  form
       lengths  are  used, and bitstrings and octet strings are always encoded
       in primitive form.  This man page describes the  encoding  routines  in
       the  lber library.  See lber-decode(3) for details on the corresponding
       decoding routines.  Consult lber-types(3) for information about  types,
       allocators, and deallocators.

       Normally,  the  only  routines that need to be called by an application
       are ber_alloc_t() to allocate a BER element for encoding,  ber_printf()
       to  do  the  actual  encoding,  and  ber_flush2() to actually write the
       element.  The other routines are provided for those  applications  that
       need  more  control  than  ber_printf()  provides.   In  general, these
       routines return the length of the element encoded, or -1  if  an  error
       occurred.

       The  ber_alloc_t()  routine  is used to allocate a new BER element.  It
       should be called with an argument of LBER_USE_DER.

       The ber_flush2() routine is used to actually write  the  element  to  a
       socket  (or  file)  descriptor,  once  it has been fully encoded (using
       ber_printf() and friends).  See lber-sockbuf(3) for more details on the
       Sockbuf implementation of the sb parameter.  If the freeit parameter is
       non-zero,    the    supplied     ber     will     be     freed.      If
       LBER_FLUSH_FREE_ON_SUCCESS   is  used,  the  ber  is  only  freed  when
       successfully   flushed,   otherwise   it    is    left    intact;    if
       LBER_FLUSH_FREE_ON_ERROR  is  used, the ber is only freed when an error
       occurs, otherwise it is left intact; if LBER_FLUSH_FREE_ALWAYS is used,
       the  ber  is  freed  anyway.   This  function differs from the original
       ber_flush(3) function, whose behavior corresponds to that indicated for
       LBER_FLUSH_FREE_ON_SUCCESS.   Note  that in the future, the behavior of
       ber_flush(3)  with  freeit  non-zero  might   change   into   that   of
       ber_flush2(3) with freeit set to LBER_FLUSH_FREE_ALWAYS.

       The  ber_printf()  routine  is used to encode a BER element in much the
       same way that sprintf(3) works.  One important difference,  though,  is
       that  some  state  information  is  kept with the ber parameter so that
       multiple calls can be made to ber_printf() to append things to the  end
       of  the  BER  element.   Ber_printf()  writes  to  ber,  a pointer to a
       BerElement such  as  returned  by  ber_alloc_t().   It  interprets  and
       formats  its  arguments according to the format string fmt.  The format
       string can contain the following characters:

              b  Boolean.  An  ber_int_t  parameter  should  be  supplied.   A
                 boolean element is output.

              e  Enumeration.   An ber_int_t parameter should be supplied.  An
                 enumeration element is output.

              i  Integer.  An ber_int_t  parameter  should  be  supplied.   An
                 integer element is output.

              B  Bitstring.  A char * pointer to the start of the bitstring is
                 supplied, followed by the number of bits in the bitstring.  A
                 bitstring element is output.

              n  Null.  No parameter is required.  A null element is output.

              o  Octet  string.   A char * is supplied, followed by the length
                 of the string pointed to.  An octet string element is output.

              O  Octet  string.   A  struct  berval  *  is supplied.  An octet
                 string element is output.

              s  Octet string.  A  null-terminated  string  is  supplied.   An
                 octet  string  element  is output, not including the trailing
                 NULL octet.

              t  Tag.  A ber_tag_t specifying the tag to give the next element
                 is provided.  This works across calls.

              v  Several  octet  strings.  A null-terminated array of char *'s
                 is supplied.  Note that a construct like '{v}' is required to
                 get an actual SEQUENCE OF octet strings.

              V  Several  octet  strings.   A  null-terminated array of struct
                 berval *'s is supplied.  Note that a construct like '{V}'  is
                 required to get an actual SEQUENCE OF octet strings.

              W  Several  octet  strings.   An  array  of  struct  berval's is
                 supplied.  The array is terminated by a struct berval with  a
                 NULL bv_val.  Note that a construct like '{W}' is required to
                 get an actual SEQUENCE OF octet strings.

              {  Begin sequence.  No parameter is required.

              }  End sequence.  No parameter is required.

              [  Begin set.  No parameter is required.

              ]  End set.  No parameter is required.

       The ber_put_int() routine writes the integer element  num  to  the  BER
       element ber.

       The  ber_put_enum()  routine  writes the enumeration element num to the
       BER element ber.

       The ber_put_boolean() routine writes the boolean value given by bool to
       the BER element.

       The  ber_put_bitstring()  routine writes blen bits starting at str as a
       bitstring value to the given BER element.  Note that blen is the length
       in bits of the bitstring.

       The  ber_put_ostring()  routine writes len bytes starting at str to the
       BER element as an octet string.

       The ber_put_string() routine writes the null-terminated  string  (minus
       the terminating ' ') to the BER element as an octet string.

       The ber_put_null() routine writes a NULL element to the BER element.

       The  ber_start_seq()  routine  is  used  to start a sequence in the BER
       element.  The ber_start_set() routine works similarly.  The end of  the
       sequence or set is marked by the nearest matching call to ber_put_seq()
       or ber_put_set(), respectively.

EXAMPLES

       Assuming the following variable declarations, and  that  the  variables
       have  been  assigned  appropriately,  an lber encoding of the following
       ASN.1 object:

             AlmostASearchRequest := SEQUENCE {
                 baseObject      DistinguishedName,
                 scope           ENUMERATED {
                     baseObject    (0),
                     singleLevel   (1),
                     wholeSubtree  (2)
                 },
                 derefAliases    ENUMERATED {
                     neverDerefaliases   (0),
                     derefInSearching    (1),
                     derefFindingBaseObj (2),
                     alwaysDerefAliases  (3)
                 },
                 sizelimit       INTEGER (0 .. 65535),
                 timelimit       INTEGER (0 .. 65535),
                 attrsOnly       BOOLEAN,
                 attributes      SEQUENCE OF AttributeType
             }

       can be achieved like so:

             int rc;
             ber_int_t    scope, ali, size, time, attrsonly;
             char   *dn, **attrs;
             BerElement *ber;

             /* ... fill in values ... */

             ber = ber_alloc_t( LBER_USE_DER );

             if ( ber == NULL ) {
                     /* error */
             }

             rc = ber_printf( ber, "{siiiib{v}}", dn, scope, ali,
                 size, time, attrsonly, attrs );

             if( rc == -1 ) {
                     /* error */
             } else {
                     /* success */
             }

ERRORS

       If an error occurs during encoding, generally these routines return -1.

NOTES

       The  return  values  for  all  of  these  functions are declared in the
       <lber.h> header file.

SEE ALSO

       lber-decode(3), lber-memory(3), lber-sockbuf(3), lber-types(3)

ACKNOWLEDGEMENTS

       OpenLDAP Software is developed and maintained by The  OpenLDAP  Project
       <http://www.openldap.org/>.    OpenLDAP   Software   is   derived  from
       University of Michigan LDAP 3.3 Release.