out_str.c

/* mpf_out_str (stream, base, n_digits, op) -- Print N_DIGITS digits from
   the float OP to STREAM in base BASE.  Return the number of characters
   written, or 0 if an error occurred.

Copyright 1996, 1997, 2001, 2002, 2005 Free Software Foundation, Inc.

This file is part of the GNU MP Library.

The GNU MP Library is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 3 of the License, or (at your
option) any later version.

The GNU MP Library is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
License for more details.

You should have received a copy of the GNU Lesser General Public License
along with the GNU MP Library.  If not, see http://www.gnu.org/licenses/.  */

#define _GNU_SOURCE    /* for DECIMAL_POINT in langinfo.h */

#include "config.h"

#include <stdio.h>
#include <string.h>

#if HAVE_LANGINFO_H
#include <langinfo.h>  /* for nl_langinfo */
#endif

#if HAVE_LOCALE_H
#include <locale.h>    /* for localeconv */
#endif

#include "gmp.h"
#include "gmp-impl.h"


size_t
mpf_out_str (FILE *stream, int base, size_t n_digits, mpf_srcptr op)
{
  char *str;
  mp_exp_t exp;
  size_t written;
  TMP_DECL;

  TMP_MARK;

  if (base == 0)
    base = 10;
  if (n_digits == 0)
    MPF_SIGNIFICANT_DIGITS (n_digits, base, op->_mp_prec);

  if (stream == 0)
    stream = stdout;

  /* Consider these changes:
     * Don't allocate memory here for huge n_digits; pass NULL to mpf_get_str.
     * Make mpf_get_str allocate extra space when passed NULL, to avoid
       allocating two huge string buffers.
     * Implement more/other allocation reductions tricks.  */

  str = (char *) TMP_ALLOC (n_digits + 2); /* extra for minus sign and \0 */

  mpf_get_str (str, &exp, base, n_digits, op);
  n_digits = strlen (str);

  written = 0;

  /* Write sign */
  if (str[0] == '-')
    {
      str++;
      fputc ('-', stream);
      written = 1;
      n_digits--;
    }

  {
    const char  *point = GMP_DECIMAL_POINT;
    size_t      pointlen = strlen (point);
    putc ('0', stream);
    fwrite (point, 1, pointlen, stream);
    written += pointlen + 1;
  }

  /* Write mantissa */
  {
    size_t fwret;
    fwret = fwrite (str, 1, n_digits, stream);
    written += fwret;
  }

  /* Write exponent */
  {
    int fpret;
    fpret = fprintf (stream, (base <= 10 ? "e%ld" : "@%ld"), exp);
    written += fpret;
  }

  TMP_FREE;
  return ferror (stream) ? 0 : written;
}