LDAP contains functions that may be used to encode and decode
    BER-encoded ASN.1 values, which are often used inside of control
    and extension values.

    The following additional integral types are defined for use in
    manipulation of BER encoded ASN.1 values:

    typedef unsigned long ber_tag_t; /* for BER tags */

    typedef long     ber_int_t; /* for BER ints, enums, and Booleans */

    With the exceptions of two new functions, ber_flatten() and ber_
    init(), these functions are compatible with the University of
    Michigan LDAP 3.3 implementation of BER.

            typedef struct berval {
                    ber_len_t            bv_len;
                    char                 *bv_val;
            } BerValue;

    A struct berval contains a sequence of bytes and an indication
    of its length. The bv_val is not null terminated. A bv_len must
    always be a nonnegative number. Applications may allocate their
    own berval structures.

            typedef struct berelement {
                 /* opaque */
            } BerElement;

    The BerElement structure contains not only a copy of the encoded
    value, but also state information used in encoding or decoding.
    Applications cannot allocate their own BerElement structures.
    The internal state is neither thread-specific nor locked, so
    two threads should not manipulate the same BerElement value
    simultaneously.

    A single BerElement value cannot be used for both encoding and
    decoding.

            void ber_bvfree( struct berval *bv );

    The ber_bvfree() function frees a berval returned from this
    API. Both the bv->bv_val string and the berval itself are freed.
    Applications should not use ber_bvfree() with bervals which the
    application has allocated.

            void ber_bvecfree ( struct berval **bv );

    The ber_bvecfree() function frees an array of bervals returned
    from this API. Each of the bervals in the array are freed using
    ber_bvfree(), then the array itself is freed.

            struct berval *ber_bvdup (struct berval *bv );

    The ber_bvdup() function returns a copy of a berval. The bv_val
    field in the returned berval points to a different area of memory
    as the bv_val field in the argument berval. The null pointer is
    returned on error (for example, out of memory).

            void ber_free ( BerElement *ber, int fbuf );

    The ber_free() function frees a BerElement which is returned from
    the API calls ber_alloc_t() or ber_init().  Each BerElement must
    be freed by the caller. The second argument fbuf should always
    be set to 1 to ensure that the internal buffer used by the BER
    functions is freed as well as the BerElement container itself.