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

   1 /* -*-c-*-
   2  *
   3  * $Id: field-parse.c,v 1.3 2004/04/03 03:32:05 mdw Exp $
   4  *
   5  * Parse field descriptions
   6  *
   7  * (c) 2004 Straylight/Edgeware
   8  */
   9
  10 /*----- Licensing notice --------------------------------------------------*
  11  *
  12  * This file is part of Catacomb.
  13  *
  14  * Catacomb is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU Library General Public License as
  16  * published by the Free Software Foundation; either version 2 of the
  17  * License, or (at your option) any later version.
  18  *
  19  * Catacomb 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 Library General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU Library General Public
  25  * License along with Catacomb; if not, write to the Free
  26  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  27  * MA 02111-1307, USA.
  28  */
  29
  30 /*----- Revision history --------------------------------------------------*
  31  *
  32  * $Log: field-parse.c,v $
  33  * Revision 1.3  2004/04/03 03:32:05  mdw
  34  * General robustification.
  35  *
  36  * Revision 1.2  2004/04/01 21:28:41  mdw
  37  * Normal basis support (translates to poly basis internally).  Rewrite
  38  * EC and prime group table generators in awk, so that they can reuse data
  39  * for repeated constants.
  40  *
  41  * Revision 1.1  2004/03/27 17:54:11  mdw
  42  * Standard curves and curve checking.
  43  *
  44  */
  45
  46 /*----- Header files ------------------------------------------------------*/
  47
  48 #include "field.h"
  49
  50 /*----- Main code ---------------------------------------------------------*/
  51
  52 /* --- @field_parse@ --- *
  53  *
  54  * Arguments:   @qd_parse *qd@ = parser context
  55  *
  56  * Returns:     Field pointer if OK, or null.
  57  *
  58  * Use:         Parses a field description, which has the form
  59  *
  60  *                * `prime', `niceprime' or `binpoly'
  61  *                * an optional `:'
  62  *                * the field modulus
  63  */
  64
  65 field *field_parse(qd_parse *qd)
  66 {
  67   field *f = 0;
  68   mp *m = MP_NEW, *b = MP_NEW;
  69
  70   switch (qd_enum(qd, "prime,niceprime,binpoly,binnorm")) {
  71     case 0:
  72       qd_delim(qd, ':');
  73       if ((m = qd_getmp(qd)) == 0) goto done;
  74       f = field_prime(m);
  75       break;
  76     case 1:
  77       qd_delim(qd, ':');
  78       if ((m = qd_getmp(qd)) == 0) goto done;
  79       f = field_niceprime(m);
  80       break;
  81     case 2:
  82       qd_delim(qd, ':');
  83       if ((m = qd_getmp(qd)) == 0) goto done;
  84       f = field_binpoly(m);
  85       break;
  86     case 3:
  87       qd_delim(qd, ':');
  88       if ((m = qd_getmp(qd)) == 0) goto done;
  89       qd_delim(qd, ',');
  90       if ((b = qd_getmp(qd)) == 0) goto done;
  91       f = field_binnorm(m, b);
  92       break;
  93     default:
  94       goto done;
  95   }
  96   if (!f) qd->e = "bad field parameters";
  97 done:
  98   mp_drop(m);
  99   mp_drop(b);
 100   return (f);
 101 }
 102
 103 /*----- That's all, folks -------------------------------------------------*/