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LBER_ENCODE(3)                                                                                LBER_ENCODE(3)



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 encod-ing encoding
       ing

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  bit-strings bitstrings
       strings 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 argu-ment argument
       ment 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  inter-prets interprets
       prets  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 con-struct construct
                 struct 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() rou-tine routine
       tine  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  appropri-ately, appropriately,
       ately, 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.



OpenLDAP 2.4.28                                  2011/11/24                                   LBER_ENCODE(3)