decode_asn1.py 文件源码

def _asn1_string_to_utf8(backend, asn1_string):
    buf = backend._ffi.new("unsigned char **")
    res = backend._lib.ASN1_STRING_to_UTF8(buf, asn1_string)
    if res == -1:
        raise ValueError(
            "Unsupported ASN1 string type. Type: {0}".format(asn1_string.type)
        )

    backend.openssl_assert(buf[0] != backend._ffi.NULL)
    buf = backend._ffi.gc(
        buf, lambda buffer: backend._lib.OPENSSL_free(buffer[0])
    )
    return backend._ffi.buffer(buf[0], res)[:].decode('utf8')