security/nss/lib/util/secasn1u.c

   1 /* ***** BEGIN LICENSE BLOCK *****
   2  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
   3  *
   4  * The contents of this file are subject to the Mozilla Public License Version
   5  * 1.1 (the "License"); you may not use this file except in compliance with
   6  * the License. You may obtain a copy of the License at
   7  * http://www.mozilla.org/MPL/
   8  *
   9  * Software distributed under the License is distributed on an "AS IS" basis,
  10  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
  11  * for the specific language governing rights and limitations under the
  12  * License.
  13  *
  14  * The Original Code is the Netscape security libraries.
  15  *
  16  * The Initial Developer of the Original Code is
  17  * Netscape Communications Corporation.
  18  * Portions created by the Initial Developer are Copyright (C) 1994-2000
  19  * the Initial Developer. All Rights Reserved.
  20  *
  21  * Contributor(s):
  22  *
  23  * Alternatively, the contents of this file may be used under the terms of
  24  * either the GNU General Public License Version 2 or later (the "GPL"), or
  25  * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
  26  * in which case the provisions of the GPL or the LGPL are applicable instead
  27  * of those above. If you wish to allow use of your version of this file only
  28  * under the terms of either the GPL or the LGPL, and not to allow others to
  29  * use your version of this file under the terms of the MPL, indicate your
  30  * decision by deleting the provisions above and replace them with the notice
  31  * and other provisions required by the GPL or the LGPL. If you do not delete
  32  * the provisions above, a recipient may use your version of this file under
  33  * the terms of any one of the MPL, the GPL or the LGPL.
  34  *
  35  * ***** END LICENSE BLOCK ***** */
  36
  37 /*
  38  * Utility routines to complement the ASN.1 encoding and decoding functions.
  39  *
  40  * $Id: secasn1u.c,v 1.4 2005/04/09 05:06:34 julien.pierre.bugs%sun.com Exp $
  41  */
  42
  43 #include "secasn1.h"
  44
  45
  46 /*
  47  * We have a length that needs to be encoded; how many bytes will the
  48  * encoding take?
  49  *
  50  * The rules are that 0 - 0x7f takes one byte (the length itself is the
  51  * entire encoding); everything else takes one plus the number of bytes
  52  * in the length.
  53  */
  54 int
  55 SEC_ASN1LengthLength (unsigned long len)
  56 {
  57     int lenlen = 1;
  58
  59     if (len > 0x7f) {
  60         do {
  61             lenlen++;
  62             len >>= 8;
  63         } while (len);
  64     }
  65
  66     return lenlen;
  67 }
  68
  69
  70 /*
  71  * XXX Move over (and rewrite as appropriate) the rest of the
  72  * stuff in dersubr.c!
  73  */
  74
  75
  76 /*
  77  * Find the appropriate subtemplate for the given template.
  78  * This may involve calling a "chooser" function, or it may just
  79  * be right there.  In either case, it is expected to *have* a
  80  * subtemplate; this is asserted in debug builds (in non-debug
  81  * builds, NULL will be returned).
  82  *
  83  * "thing" is a pointer to the structure being encoded/decoded
  84  * "encoding", when true, means that we are in the process of encoding
  85  *      (as opposed to in the process of decoding)
  86  */
  87 const SEC_ASN1Template *
  88 SEC_ASN1GetSubtemplate (const SEC_ASN1Template *theTemplate, void *thing,
  89                         PRBool encoding)
  90 {
  91     const SEC_ASN1Template *subt = NULL;
  92
  93     PORT_Assert (theTemplate->sub != NULL);
  94     if (theTemplate->sub != NULL) {
  95         if (theTemplate->kind & SEC_ASN1_DYNAMIC) {
  96             SEC_ASN1TemplateChooserPtr chooserp;
  97
  98             chooserp = *(SEC_ASN1TemplateChooserPtr *) theTemplate->sub;
  99             if (chooserp) {
 100                 if (thing != NULL)
 101                     thing = (char *)thing - theTemplate->offset;
 102                 subt = (* chooserp)(thing, encoding);
 103             }
 104         } else {
 105             subt = (SEC_ASN1Template*)theTemplate->sub;
 106         }
 107     }
 108     return subt;
 109 }
 110
 111 PRBool SEC_ASN1IsTemplateSimple(const SEC_ASN1Template *theTemplate)
 112 {
 113     if (!theTemplate) {
 114         return PR_TRUE; /* it doesn't get any simpler than NULL */
 115     }
 116     /* only templates made of one primitive type or a choice of primitive
 117        types are considered simple */
 118     if (! (theTemplate->kind & (~SEC_ASN1_TAGNUM_MASK))) {
 119         return PR_TRUE; /* primitive type */
 120     }
 121     if (!theTemplate->kind & SEC_ASN1_CHOICE) {
 122         return PR_FALSE; /* no choice means not simple */
 123     }
 124     while (++theTemplate && theTemplate->kind) {
 125         if (theTemplate->kind & (~SEC_ASN1_TAGNUM_MASK)) {
 126             return PR_FALSE; /* complex type */
 127         }
 128     }
 129     return PR_TRUE; /* choice of primitive types */
 130 }
 131