git.distorted.org.uk Git - u/mdw/catacomb/blob - group-parse.c

   1 /* -*-c-*-
   2  *
   3  * $Id: group-parse.c,v 1.3 2004/04/08 01:36:15 mdw Exp $
   4  *
   5  * Parse group description strings
   6  *
   7  * (c) 2004 Straylight/Edgeware
   8  */
   9
  10 /*----- Licensing notice --------------------------------------------------*
  11  *
  12  * This file is part of Trivial IP Encryption (TrIPE).
  13  *
  14  * TrIPE is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU General Public License as published by
  16  * the Free Software Foundation; either version 2 of the License, or
  17  * (at your option) any later version.
  18  *
  19  * TrIPE is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU General Public License
  25  * along with TrIPE; if not, write to the Free Software Foundation,
  26  * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  27  */
  28
  29 /*----- Header files ------------------------------------------------------*/
  30
  31 #include "group.h"
  32 #include "dh.h"
  33
  34 /*----- Main code ---------------------------------------------------------*/
  35
  36 /* --- @group_parse@ --- *
  37  *
  38  * Arguments:   @qd_parse *qd@ = quick-and-dirty parser
  39  *
  40  * Returns:     Group pointer, or null for failure.
  41  *
  42  * Use:         Parses a group description and returns the group.  This has
  43  *              the form `TYPE { SPEC }' where TYPE is `prime' or `ec', and
  44  *              SPEC is the appropriate kind of group specification of the
  45  *              given type.
  46  */
  47
  48 group *group_parse(qd_parse *qd)
  49 {
  50   group *g = 0;
  51
  52   switch (qd_enum(qd, "prime,ec")) {
  53     case 0: {
  54       dh_param dp;
  55       qd_delim(qd, '{');
  56       if (dh_parse(qd, &dp)) goto ouch;
  57       qd_delim(qd, '}');
  58       g = group_prime(&dp);
  59       dh_paramfree(&dp);
  60     } break;
  61     case 1: {
  62       ec_info ei;
  63       qd_delim(qd, '{');
  64       if (ec_infoparse(qd, &ei)) goto ouch;
  65       qd_delim(qd, '}');
  66       g = group_ec(&ei);
  67     } break;
  68   }
  69   if (!g) qd->e = "bad group parameters";
  70 ouch:
  71   return (g);
  72 }
  73
  74 /* --- @group_fromstring@ --- *
  75  *
  76  * Arguments:   @const char *p@ = pointer to string to read
  77  *              @group **gg@ = where to put the group pointer
  78  *
  79  * Returns:     Null if OK, or an error string.
  80  *
  81  * Use:         Parses a group spec from a string, and returns the group.
  82  */
  83
  84 const char *group_fromstring(const char *p, group **gg)
  85 {
  86   group *g;
  87   qd_parse qd;
  88
  89   qd.p = p;
  90   qd.e = 0;
  91   if ((g = group_parse(&qd)) == 0) return (qd.e);
  92   if (!qd_eofp(&qd)) { G_DESTROYGROUP(g); return ("junk at end of string"); }
  93   *gg = g;
  94   return (0);
  95 }
  96
  97 /*----- That's all, folks -------------------------------------------------*/