1/*
2 * The contents of this file are subject to the Mozilla Public
3 * License Version 1.1 (the "License"); you may not use this file
4 * except in compliance with the License. You may obtain a copy of
5 * the License at http://www.mozilla.org/MPL/
6 *
7 * Software distributed under the License is distributed on an "AS
8 * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
9 * implied. See the License for the specific language governing
10 * rights and limitations under the License.
11 *
12 * The Original Code is the Netscape security libraries.
13 *
14 * The Initial Developer of the Original Code is Netscape
15 * Communications Corporation.  Portions created by Netscape are
16 * Copyright (C) 1994-2000 Netscape Communications Corporation.  All
17 * Rights Reserved.
18 *
19 * Contributor(s):
20 *
21 * Alternatively, the contents of this file may be used under the
22 * terms of the GNU General Public License Version 2 or later (the
23 * "GPL"), in which case the provisions of the GPL are applicable
24 * instead of those above.  If you wish to allow use of your
25 * version of this file only under the terms of the GPL and not to
26 * allow others to use your version of this file under the MPL,
27 * indicate your decision by deleting the provisions above and
28 * replace them with the notice and other provisions required by
29 * the GPL.  If you do not delete the provisions above, a recipient
30 * may use your version of this file under either the MPL or the
31 * GPL.
32 */
33
34/*
35 * Utility routines to complement the ASN.1 encoding and decoding functions.
36 *
37 * $Id: secasn1u.c,v 1.3 2004/05/13 15:29:13 dmitch Exp $
38 */
39
40#include "secasn1.h"
41
42
43/*
44 * We have a length that needs to be encoded; how many bytes will the
45 * encoding take?
46 *
47 * The rules are that 0 - 0x7f takes one byte (the length itself is the
48 * entire encoding); everything else takes one plus the number of bytes
49 * in the length.
50 */
51int
52SEC_ASN1LengthLength (unsigned long len)
53{
54    int lenlen = 1;
55
56    if (len > 0x7f) {
57	do {
58	    lenlen++;
59	    len >>= 8;
60	} while (len);
61    }
62
63    return lenlen;
64}
65
66
67/*
68 * XXX Move over (and rewrite as appropriate) the rest of the
69 * stuff in dersubr.c!
70 */
71
72
73/*
74 * Find the appropriate subtemplate for the given template.
75 * This may involve calling a "chooser" function, or it may just
76 * be right there.  In either case, it is expected to *have* a
77 * subtemplate; this is asserted in debug builds (in non-debug
78 * builds, NULL will be returned).
79 *
80 * "thing" is a pointer to the structure being encoded/decoded
81 * "encoding", when true, means that we are in the process of encoding
82 *	(as opposed to in the process of decoding)
83 */
84const SecAsn1Template *
85SEC_ASN1GetSubtemplate (
86	const SecAsn1Template *theTemplate,
87	void *thing,
88	PRBool encoding
89	#ifdef	__APPLE__
90	,
91	const char *buf			// for decode only
92	#endif
93	)
94{
95    const SecAsn1Template *subt = NULL;
96
97    PORT_Assert (theTemplate->sub != NULL);
98    if (theTemplate->sub != NULL) {
99	if (theTemplate->kind & SEC_ASN1_DYNAMIC) {
100	    SecAsn1TemplateChooserPtr chooserp;
101
102	    chooserp = *(SecAsn1TemplateChooserPtr *) theTemplate->sub;
103	    if (chooserp) {
104			void *dest = thing;
105			if (thing != NULL) {
106				thing = (char *)thing - theTemplate->offset;
107			}
108			subt = (* chooserp)(thing, encoding, buf, dest);
109	    }
110	} else {
111	    subt = (SecAsn1Template*)theTemplate->sub;
112	}
113    }
114    return subt;
115}
116