OSX/libsecurity_asn1/lib/secasn1u.c

   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  */
  51 int
  52 SEC_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  */
  84 const SecAsn1Template *
  85 SEC_ASN1GetSubtemplate (
  86         const SecAsn1Template *theTemplate,
  87         void *thing,
  88         PRBool encoding
  89         #ifdef  __APPLE__
  90         ,
  91         const char *buf,                        // for decode only
  92         size_t len
  93         #endif
  94         )
  95 {
  96     const SecAsn1Template *subt = NULL;
  97
  98     PORT_Assert (theTemplate->sub != NULL);
  99     if (theTemplate->sub != NULL) {
 100         if (theTemplate->kind & SEC_ASN1_DYNAMIC) {
 101             SecAsn1TemplateChooserPtr chooserp;
 102
 103             chooserp = *(SecAsn1TemplateChooserPtr *) theTemplate->sub;
 104             if (chooserp) {
 105                         void *dest = thing;
 106                         if (thing != NULL) {
 107                                 thing = (char *)thing - theTemplate->offset;
 108                         }
 109                         subt = (* chooserp)(thing, encoding, buf, len, dest);
 110             }
 111         } else {
 112             subt = (SecAsn1Template*)theTemplate->sub;
 113         }
 114     }
 115     return subt;
 116 }