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

   1 /* -*-c-*-
   2  *
   3  * Reading and writing large integers on strings
   4  *
   5  * (c) 1999 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 <string.h>
  31
  32 #include "mptext.h"
  33
  34 /*----- Main code ---------------------------------------------------------*/
  35
  36 /* --- Operations table --- */
  37
  38 static int get(void *p)
  39 {
  40   mptext_stringctx *c = p;
  41   if (c->buf >= c->lim)
  42     return (EOF);
  43   return ((unsigned char)*c->buf++);
  44 }
  45
  46 static void unget(int ch, void *p)
  47 {
  48   mptext_stringctx *c = p;
  49   if (ch != EOF)
  50     c->buf--;
  51 }
  52
  53 static int put(const char *s, size_t sz, void *p)
  54 {
  55   mptext_stringctx *c = p;
  56   int rc = 0;
  57   if (sz > c->lim - c->buf) {
  58     sz = c->lim - c->buf;
  59     rc = EOF;
  60   }
  61   if (sz) {
  62     memcpy(c->buf, s, sz);
  63     c->buf += sz;
  64   }
  65   return (rc);
  66 }
  67
  68 const mptext_ops mptext_stringops = { get, unget, put };
  69
  70 /* --- Convenience functions --- */
  71
  72 mp *mp_readstring(mp *m, const char *p, char **end, int radix)
  73 {
  74   mptext_stringctx c;
  75   c.buf = (/*unconst */ char *)p;
  76   c.lim = c.buf + strlen(p);
  77   m = mp_read(m, radix, &mptext_stringops, &c);
  78   if (end)
  79     *end = c.buf;
  80   return (m);
  81 }
  82
  83 int mp_writestring(mp *m, char *p, size_t sz, int radix)
  84 {
  85   mptext_stringctx c;
  86   int rc;
  87   if (!sz)
  88     return (0);
  89   c.buf = p;
  90   c.lim = p + sz - 1;
  91   rc = mp_write(m, radix, &mptext_stringops, &c);
  92   *c.buf = 0;
  93   return (rc);
  94 }
  95
  96 /*----- That's all, folks -------------------------------------------------*/