SecuritySNACCRuntime/c-lib/src/asn-tag.c

   1 /*
   2  * Copyright (c) 2000-2001 Apple Computer, Inc. All Rights Reserved.
   3  *
   4  * The contents of this file constitute Original Code as defined in and are
   5  * subject to the Apple Public Source License Version 1.2 (the 'License').
   6  * You may not use this file except in compliance with the License. Please obtain
   7  * a copy of the License at http://www.apple.com/publicsource and read it before
   8  * using this file.
   9  *
  10  * This Original Code and all software distributed under the License are
  11  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS
  12  * OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, INCLUDING WITHOUT
  13  * LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
  14  * PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. Please see the License for the
  15  * specific language governing rights and limitations under the License.
  16  */
  17
  18
  19 /*
  20  * asn_tag.c - BER encode, decode and untility routines for ASN.1 Tags.
  21  *
  22  * MS 92
  23  * Copyright (C) 1992 Michael Sample and the University of British Columbia
  24  *
  25  * This library is free software; you can redistribute it and/or
  26  * modify it provided that this copyright/license information is retained
  27  * in original form.
  28  *
  29  * If you modify this file, you must clearly indicate your changes.
  30  *
  31  * This source code is distributed in the hope that it will be
  32  * useful, but WITHOUT ANY WARRANTY; without even the implied warranty
  33  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  34  *
  35  * $Header: /cvs/Darwin/src/live/Security/SecuritySNACCRuntime/c-lib/src/asn-tag.c,v 1.1.1.1 2001/05/18 23:14:08 mb Exp $
  36  * $Log: asn-tag.c,v $
  37  * Revision 1.1.1.1  2001/05/18 23:14:08  mb
  38  * Move from private repository to open source repository
  39  *
  40  * Revision 1.2  2001/05/05 00:59:25  rmurphy
  41  * Adding darwin license headers
  42  *
  43  * Revision 1.1.1.1  1999/03/16 18:06:32  aram
  44  * Originals from SMIME Free Library.
  45  *
  46  * Revision 1.5  1997/09/03 12:11:41  wan
  47  * Patch to tag decoding for tags > 2^14 (thanks to Enrico Badella)
  48  * Patch to TblEncTag to emit final 0x00 if previous octet signals continuation
  49  *
  50  * Revision 1.4  1997/03/13 09:15:18  wan
  51  * Improved dependency generation for stupid makedepends.
  52  * Corrected PeekTag to peek into buffer only as far as necessary.
  53  * Added installable error handler.
  54  * Fixed small glitch in idl-code generator (Markku Savela <msa@msa.tte.vtt.fi>).
  55  *
  56  * Revision 1.3  1997/02/28 13:39:50  wan
  57  * Modifications collected for new version 1.3: Bug fixes, tk4.2.
  58  *
  59  * Revision 1.2  1995/07/27 09:01:25  rj
  60  * merged PeekTag(), a function used only by the type table code.
  61  *
  62  * changed `_' to `-' in file names.
  63  *
  64  * Revision 1.1  1994/08/28  09:46:01  rj
  65  * first check-in. for a list of changes to the snacc-1.1 distribution please refer to the ChangeLog.
  66  *
  67  */
  68
  69 #include "asn-config.h"
  70 #include "asn-len.h"
  71 #include "asn-tag.h"
  72
  73
  74 /*
  75  * Returns an AsnTag.  An AsnTag is simply an encoded tag
  76  * shifted to fill up an unsigned long int (first tag byte
  77  * in most sig byte of long int)
  78  * This rep permits easy case stmt comparison of tags.
  79  * NOTE: The unsigned long rep for tag BREAKS if the
  80  *       the tag's code is over 2^21 (very unlikely)
  81  *
  82  * RETURNS 0 if decoded a 0 byte (ie first byte of an EOC)
  83  */
  84 AsnTag
  85 BDecTag PARAMS ((b, bytesDecoded, env),
  86     BUF_TYPE  b _AND_
  87     AsnLen *bytesDecoded _AND_
  88     jmp_buf env)
  89 {
  90     AsnTag tagId;
  91     AsnTag tmpTagId;
  92     int i;
  93
  94     tagId = ((AsnTag)BufGetByte (b)) << ((sizeof (AsnTag)-1)*8);
  95     (*bytesDecoded)++;
  96
  97     /* check if long tag format (ie code > 31) */
  98     if ((tagId & (((AsnTag) 0x1f) << ((sizeof (AsnTag)-1)*8))) == (((AsnTag)0x1f) << ((sizeof (AsnTag)-1)*8)))
  99     {
 100         i = 2;
 101         do
 102         {
 103             tmpTagId = (AsnTag) BufGetByte (b);
 104             tagId |= (tmpTagId << ((sizeof (AsnTag)-i)*8));
 105             (*bytesDecoded)++;
 106             i++;
 107         }
 108         while ((tmpTagId & (AsnTag)0x80) && (i <= sizeof (AsnTag)));
 109
 110         /*
 111          * check for tag that is too long
 112          */
 113         if (i > (sizeof (AsnTag)+1))
 114         {
 115             Asn1Error ("BDecTag: ERROR - tag value overflow\n");
 116             longjmp (env, -25);
 117         }
 118     }
 119
 120     if (BufReadError (b))
 121     {
 122         Asn1Error ("BDecTag: ERROR - decoded past the end of data\n");
 123         longjmp (env, -26);
 124     }
 125
 126     return tagId;
 127
 128 }  /* BDecTag */
 129
 130
 131 #if TTBL
 132 AsnTag PeekTag PARAMS ((b, env),
 133     BUF_TYPE b _AND_
 134     ENV_TYPE env)
 135 {
 136     AsnTag tagId, tmpTagId;
 137     int i;
 138     unsigned char buf[sizeof(AsnTag)];
 139     unsigned char* p = buf;
 140
 141     /*
 142      * peek/copy the next (max size of tag) bytes
 143      * to get the tag info.  The Peek buffer routines
 144      * were added to the standard set for this function.
 145      */
 146
 147     BufPeekCopy ((char*)buf, b, 1);
 148     tagId = ((AsnTag)*p++) << ((sizeof (AsnTag)-1)*8);
 149
 150     /* check if long tag format (ie code > 31) */
 151     if ((tagId & (((AsnTag) 0x1f) << ((sizeof (AsnTag)-1)*8))) == (((AsnTag)0x1f) << ((sizeof (AsnTag)-1)*8)))
 152     {
 153         i = 2;
 154         do
 155         {
 156             BufPeekCopy ((char*)buf, b, i);
 157             tmpTagId = (AsnTag) *p++;
 158             tagId |= (tmpTagId << ((sizeof (AsnTag)-i)*8));
 159             i++;
 160         }
 161         while ((tmpTagId & (AsnTag)0x80) && (i <= sizeof (AsnTag)));
 162
 163         /*
 164          * check for tag that is too long
 165          */
 166         if (i > (sizeof (AsnTag)+1))
 167         {
 168             Asn1Error ("BDecTag: ERROR - tag value overflow\n");
 169             longjmp (env, -1004);
 170         }
 171     }
 172
 173     return tagId;
 174
 175 } /* PeekTag */
 176 #endif /* TTBL */