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LBER_ENCODE(3)                                 Library Functions Manual                                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 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  ele‐
       ment  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.
       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 accord‐
       ing 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 includ‐
                 ing 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  con‐
                 struct 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 ele‐
       ment.  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.
       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)