decode and encode ASN.1 object
**val_out, unsigned char **der_in,
*val_in, unsigned char **der_out);
These functions decode and encode ASN.1 object identifiers. For details about the semantics, examples, caveats, and bugs, see ASN1_item_d2i(3).
The LibreSSL implementation of
ASN1_OBJECT_free(3) if an existing object is passed in via
val_out and it always creates a new object from
scratch. Other implementations may attempt to reuse an existing object,
which is fragile and prone to bugs. Consequently, always passing
NULL for the val_out argument
The objects returned from
and the data contained in them are always marked as dynamically allocated,
so when they are no longer needed,
ASN1_OBJECT_free(3) can be called on them.
d2i_ASN1_OBJECT() returns a pointer to the
new ASN1_OBJECT object or
if an error occurs. With other implementations, it might return a pointer to
the reused ASN1_OBJECT.
i2d_ASN1_OBJECT() returns the number of
bytes successfully encoded or a value <= 0 if an error occurs.
a2d_ASN1_OBJECT(3), ASN1_item_d2i(3), ASN1_OBJECT_new(3), OBJ_nid2obj(3)
ITU-T Recommendation X.690, also known as ISO/IEC 8825-1: Information technology - ASN.1 encoding rules: Specification of Basic Encoding Rules (BER), Canonical Encoding Rules (CER) and Distinguished Encoding Rules (DER), section 8.19: Encoding of an object identifier value
i2d_ASN1_OBJECT() first appeared in SSLeay 0.5.1 and
have been available since OpenBSD 2.4.
d2i_ASN1_OBJECT() never sets the long and
short names of the object, not even if the object identifier matches one
that is built into the library. To find the names of an object identifier
parsed from DER or BER input, call
OBJ_obj2nid(3) on the returned object, and then
OBJ_nid2ln(3) on the result.