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

   1 /* -*-c-*-
   2  *
   3  * Parse field descriptions
   4  *
   5  * (c) 2004 Straylight/Edgeware
   6  */
   7
   8 /*----- Licensing notice --------------------------------------------------*
   9  *
  10  * This file is part of Catacomb.
  11  *
  12  * Catacomb is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU Library General Public License as
  14  * published by the Free Software Foundation; either version 2 of the
  15  * License, or (at your option) any later version.
  16  *
  17  * Catacomb is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU Library General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU Library General Public
  23  * License along with Catacomb; if not, write to the Free
  24  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  25  * MA 02111-1307, USA.
  26  */
  27
  28 /*----- Header files ------------------------------------------------------*/
  29
  30 #include "field.h"
  31
  32 /*----- Main code ---------------------------------------------------------*/
  33
  34 /* --- @field_parse@ --- *
  35  *
  36  * Arguments:   @qd_parse *qd@ = parser context
  37  *
  38  * Returns:     Field pointer if OK, or null.
  39  *
  40  * Use:         Parses a field description, which has the form
  41  *
  42  *                * `prime', `niceprime' or `binpoly'
  43  *                * an optional `:'
  44  *                * the field modulus
  45  */
  46
  47 field *field_parse(qd_parse *qd)
  48 {
  49   field *f = 0;
  50   mp *m = MP_NEW, *b = MP_NEW;
  51
  52   switch (qd_enum(qd, "prime,niceprime,binpoly,binnorm")) {
  53     case 0:
  54       qd_delim(qd, ':');
  55       if ((m = qd_getmp(qd)) == 0) goto done;
  56       f = field_prime(m);
  57       break;
  58     case 1:
  59       qd_delim(qd, ':');
  60       if ((m = qd_getmp(qd)) == 0) goto done;
  61       f = field_niceprime(m);
  62       break;
  63     case 2:
  64       qd_delim(qd, ':');
  65       if ((m = qd_getmp(qd)) == 0) goto done;
  66       f = field_binpoly(m);
  67       break;
  68     case 3:
  69       qd_delim(qd, ':');
  70       if ((m = qd_getmp(qd)) == 0) goto done;
  71       qd_delim(qd, ',');
  72       if ((b = qd_getmp(qd)) == 0) goto done;
  73       f = field_binnorm(m, b);
  74       break;
  75     default:
  76       goto done;
  77   }
  78   if (!f) qd->e = "bad field parameters";
  79 done:
  80   mp_drop(m);
  81   mp_drop(b);
  82   return (f);
  83 }
  84
  85 /*----- That's all, folks -------------------------------------------------*/