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

   1 /* -*-c-*-
   2  *
   3  * $Id: mptext-string.c,v 1.2 1999/12/22 15:56:21 mdw Exp $
   4  *
   5  * Reading and writing large integers on strings
   6  *
   7  * (c) 1999 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: mptext-string.c,v $
  33  * Revision 1.2  1999/12/22 15:56:21  mdw
  34  * Make the buffer passed to `put' op constant.
  35  *
  36  * Revision 1.1  1999/11/17 18:02:16  mdw
  37  * New multiprecision integer arithmetic suite.
  38  *
  39  */
  40
  41 /*----- Header files ------------------------------------------------------*/
  42
  43 #include <string.h>
  44
  45 #include "mptext.h"
  46
  47 /*----- Main code ---------------------------------------------------------*/
  48
  49 /* --- Operations table --- */
  50
  51 static int get(void *p)
  52 {
  53   mptext_stringctx *c = p;
  54   if (c->buf >= c->lim)
  55     return (EOF);
  56   return (*c->buf++);
  57 }
  58
  59 static void unget(int ch, void *p)
  60 {
  61   mptext_stringctx *c = p;
  62   if (ch != EOF)
  63     c->buf--;
  64 }
  65
  66 static int put(const char *s, size_t sz, void *p)
  67 {
  68   mptext_stringctx *c = p;
  69   int rc = 0;
  70   if (sz > c->lim - c->buf) {
  71     sz = c->lim - c->buf;
  72     rc = EOF;
  73   }
  74   if (sz) {
  75     memcpy(c->buf, s, sz);
  76     c->buf += sz;
  77   }
  78   return (rc);
  79 }
  80
  81 const mptext_ops mptext_stringops = { get, unget, put };
  82
  83 /* --- Convenience functions --- */
  84
  85 mp *mp_readstring(mp *m, const char *p, char **end, int radix)
  86 {
  87   mptext_stringctx c;
  88   c.buf = (char *)p;
  89   c.lim = c.buf + strlen(p);
  90   m = mp_read(m, radix, &mptext_stringops, &c);
  91   if (end)
  92     *end = c.buf;
  93   return (m);
  94 }
  95
  96 int mp_writestring(mp *m, char *p, size_t sz, int radix)
  97 {
  98   mptext_stringctx c;
  99   int rc;
 100   if (!sz)
 101     return (0);
 102   c.buf = p;
 103   c.lim = p + sz - 1;
 104   rc = mp_write(m, radix, &mptext_stringops, &c);
 105   *c.buf = 0;
 106   return (rc);
 107 }
 108
 109 /*----- That's all, folks -------------------------------------------------*/