OBJ_nid2obj(3)              OpenSSL              OBJ_nid2obj(3)





NAME
       OBJ_nid2obj, OBJ_nid2ln, OBJ_nid2sn, OBJ_obj2nid,
       OBJ_txt2nid, OBJ_ln2nid, OBJ_sn2nid, OBJ_cmp, OBJ_dup,
       OBJ_txt2obj, OBJ_obj2txt, OBJ_create, OBJ_cleanup - ASN1
       object utility functions

SYNOPSIS
        ASN1_OBJECT * OBJ_nid2obj(int n);
        const char *  OBJ_nid2ln(int n);
        const char *  OBJ_nid2sn(int n);

        int OBJ_obj2nid(const ASN1_OBJECT *o);
        int OBJ_ln2nid(const char *ln);
        int OBJ_sn2nid(const char *sn);

        int OBJ_txt2nid(const char *s);

        ASN1_OBJECT * OBJ_txt2obj(const char *s, int no_name);
        int OBJ_obj2txt(char *buf, int buf_len, const ASN1_OBJECT *a, int no_name);

        int OBJ_cmp(const ASN1_OBJECT *a,const ASN1_OBJECT *b);
        ASN1_OBJECT * OBJ_dup(const ASN1_OBJECT *o);

        int OBJ_create(const char *oid,const char *sn,const char *ln);
        void OBJ_cleanup(void);

DESCRIPTION
       The ASN1 object utility functions process ASN1_OBJECT
       structures which are a representation of the ASN1 OBJECT
       IDENTIFIER (OID) type.

       OBJ_nid2obj(), OBJ_nid2ln() and OBJ_nid2sn() convert the
       NID n to an ASN1_OBJECT structure, its long name and its
       short name respectively, or NULL is an error occurred.

       OBJ_obj2nid(), OBJ_ln2nid(), OBJ_sn2nid() return the
       corresponding NID for the object o, the long name <ln>
       or the short name <sn> respectively or NID_undef if an
       error occurred.

       OBJ_txt2nid() returns NID corresponding to text string
       <s>. s can be a long name, a short name or the numerical
       respresentation of an object.

       OBJ_txt2obj() converts the text string s into an
       ASN1_OBJECT structure.  If no_name is 0 then long names
       and short names will be interpreted as well as numerical
       forms. If no_name is 1 only the numerical form is
       acceptable.

       OBJ_obj2txt() converts the ASN1_OBJECT a into a textual
       representation.  The representation is written as a null
       terminated string to buf at most buf_len bytes are writ-
       ten, truncating the result if necessary.  The total
       amount of space required is returned. If no_name is 0
       then if the object has a long or short name then that
       will be used, otherwise the numerical form will be used.
       If no_name is 1 then the numerical form will always be
       used.

       OBJ_cmp() compares a to b. If the two are identical 0 is
       returned.

       OBJ_dup() returns a copy of o.

       OBJ_create() adds a new object to the internal table.
       oid is the numerical form of the object, sn the short
       name and ln the long name. A new NID is returned for the
       created object.

       OBJ_cleanup() cleans up OpenSSLs internal object table:
       this should be called before an application exits if any
       new objects were added using OBJ_create().

NOTES
       Objects in OpenSSL can have a short name, a long name
       and a numerical identifier (NID) associated with them. A
       standard set of objects is represented in an internal
       table. The appropriate values are defined in the header
       file objects.h.

       For example the OID for commonName has the following
       definitions:

        #define SN_commonName                   "CN"
        #define LN_commonName                   "commonName"
        #define NID_commonName                  13

       New objects can be added by calling OBJ_create().

       Table objects have certain advantages over other
       objects: for example their NIDs can be used in a C lan-
       guage switch statement. They are also static constant
       structures which are shared: that is there is only a
       single constant structure for each table object.

       Objects which are not in the table have the NID value
       NID_undef.

       Objects do not need to be in the internal tables to be
       processed, the functions OBJ_txt2obj() and OBJ_obj2txt()
       can process the numerical form of an OID.

EXAMPLES
       Create an object for commonName:

        ASN1_OBJECT *o;
        o = OBJ_nid2obj(NID_commonName);

       Check if an object is commonName

        if (OBJ_obj2nid(obj) == NID_commonName)
               /* Do something */

       Create a new NID and initialize an object from it:

        int new_nid;
        ASN1_OBJECT *obj;
        new_nid = OBJ_create("1.2.3.4", "NewOID", "New Object Identifier");

        obj = OBJ_nid2obj(new_nid);

       Create a new object directly:

        obj = OBJ_txt2obj("1.2.3.4", 1);

BUGS
       OBJ_obj2txt() is awkward and messy to use: it doesn't
       follow the convention of other OpenSSL functions where
       the buffer can be set to NULL to determine the amount of
       data that should be written.  Instead buf must point to
       a valid buffer and buf_len should be set to a positive
       value. A buffer length of 80 should be more than enough
       to handle any OID encountered in practice.

RETURN VALUES
       OBJ_nid2obj() returns an ASN1_OBJECT structure or NULL
       is an error occurred.

       OBJ_nid2ln() and OBJ_nid2sn() returns a valid string or
       NULL on error.

       OBJ_obj2nid(), OBJ_ln2nid(), OBJ_sn2nid() and
       OBJ_txt2nid() return a NID or NID_undef on error.

SEE ALSO
       ERR_get_error(3)

HISTORY
       TBA



0.9.7c                     2002-10-20            OBJ_nid2obj(3)
