source/libs/mpfr/mpfr-3.1.3/src/inp_str.c

   1 /* mpfr_inp_str -- input a number in base BASE from stdio stream STREAM
   2                    and store the result in ROP
   3
   4 Copyright 1999, 2001-2002, 2004, 2006-2015 Free Software Foundation, Inc.
   5 Contributed by the AriC and Caramel projects, INRIA.
   6
   7 This file is part of the GNU MPFR Library.
   8
   9 The GNU MPFR Library is free software; you can redistribute it and/or modify
  10 it under the terms of the GNU Lesser General Public License as published by
  11 the Free Software Foundation; either version 3 of the License, or (at your
  12 option) any later version.
  13
  14 The GNU MPFR Library is distributed in the hope that it will be useful, but
  15 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  16 or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
  17 License for more details.
  18
  19 You should have received a copy of the GNU Lesser General Public License
  20 along with the GNU MPFR Library; see the file COPYING.LESSER.  If not, see
  21 http://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc.,
  22 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */
  23
  24 #include <ctype.h>
  25
  26 #include "mpfr-impl.h"
  27
  28 /* The original version of this function came from GMP's mpf/inp_str.c;
  29    it has been adapted for MPFR. */
  30
  31 size_t
  32 mpfr_inp_str (mpfr_ptr rop, FILE *stream, int base, mpfr_rnd_t rnd_mode)
  33 {
  34   unsigned char *str;
  35   size_t alloc_size, str_size;
  36   int c;
  37   int retval;
  38   size_t nread;
  39
  40   if (stream == NULL)
  41     stream = stdin;
  42
  43   alloc_size = 100;
  44   str = (unsigned char *) (*__gmp_allocate_func) (alloc_size);
  45   str_size = 0;
  46   nread = 0;
  47
  48   /* Skip whitespace.  */
  49   do
  50     {
  51       c = getc (stream);
  52       nread++;
  53     }
  54   while (isspace (c));
  55
  56   /* number of characters read is nread */
  57
  58   for (;;)
  59     {
  60       if (str_size >= alloc_size)
  61         {
  62           size_t old_alloc_size = alloc_size;
  63           alloc_size = alloc_size * 3 / 2;
  64           str = (unsigned char *)
  65             (*__gmp_reallocate_func) (str, old_alloc_size, alloc_size);
  66         }
  67       if (c == EOF || isspace (c))
  68         break;
  69       str[str_size++] = (unsigned char) c;
  70       c = getc (stream);
  71     }
  72   ungetc (c, stream);
  73
  74   /* number of characters read is nread + str_size - 1 */
  75
  76   /* we can exit the for loop only by the break instruction,
  77      then necessarily str_size >= alloc_size was checked, so
  78      now str_size < alloc_size */
  79
  80   str[str_size] = '\0';
  81
  82   retval = mpfr_set_str (rop, (char *) str, base, rnd_mode);
  83   (*__gmp_free_func) (str, alloc_size);
  84
  85   if (retval == -1)
  86     return 0;                   /* error */
  87
  88  return str_size + nread - 1;
  89 }