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

   1 /* -*-c-*-
   2  *
   3  * String I/O for group elements
   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 "group.h"
  31
  32 /*----- Main code ---------------------------------------------------------*/
  33
  34 /* --- @group_readstring@ --- *
  35  *
  36  * Arguments:   @group *g@ = an abstract group
  37  *              @ge *d@ = destination group element
  38  *              @const char *p@ = where the string is
  39  *              @char **end@ = where to put the end pointer
  40  *
  41  * Returns:     Zero on success, nonzero on failure.
  42  *
  43  * Use:         Parses a group element from a string.
  44  */
  45
  46 int group_readstring(group *g, ge *d, const char *p, char **end)
  47 {
  48   mptext_stringctx ms;
  49
  50   ms.buf = (/*unconst*/ char *)p;
  51   ms.lim = (/*unconst*/ char *)p + strlen(p);
  52   if (G_READ(g, d, &mptext_stringops, &ms))
  53     return (-1);
  54   if (end) *end = ms.buf;
  55   return (0);
  56 }
  57
  58 /* --- @group_writestring@ --- *
  59  *
  60  * Arguments:   @group *g@ = an abstract group
  61  *              @ge *x@ = a group element
  62  *              @char *p@ = where the string should go
  63  *              @size_t sz@ = how long the buffer is
  64  *
  65  * Returns:     Zero on success, nonzero on failure.
  66  *
  67  * Use:         Writes a group element to a string buffer.
  68  */
  69
  70 int group_writestring(group *g, ge *x, char *p, size_t sz)
  71 {
  72   mptext_stringctx ms;
  73
  74   ms.buf = p;
  75   ms.lim = p + sz - 1;
  76   if (G_WRITE(g, x, &mptext_stringops, &ms))
  77     return (-1);
  78   *ms.buf = 0;
  79   return (0);
  80 }
  81
  82 /*----- That's all, folks -------------------------------------------------*/