misc/efgcvt_r.c

   1 /* Compatibility functions for floating point formatting, reentrant versions.
   2    Copyright (C) 1995, 1996, 1997 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Library General Public License as
   7    published by the Free Software Foundation; either version 2 of the
   8    License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Library General Public License for more details.
  14
  15    You should have received a copy of the GNU Library General Public
  16    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  17    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18    Boston, MA 02111-1307, USA.  */
  19
  20 #include <errno.h>
  21 #include <stdio.h>
  22 #include <string.h>
  23 #include <ctype.h>
  24 #include <math.h>
  25 #include <stdlib.h>
  26
  27 #ifndef FLOAT_TYPE
  28 #define FLOAT_TYPE double
  29 #define FUNC_PREFIX
  30 #define FLOAT_FMT_FLAG
  31 #define FLOAT_NAME_EXT
  32 #endif
  33
  34 #define APPEND(a, b) APPEND2 (a, b)
  35 #define APPEND2(a, b) a##b
  36
  37 #define FLOOR APPEND(floor, FLOAT_NAME_EXT)
  38 #define FABS APPEND(fabs, FLOAT_NAME_EXT)
  39 #define LOG10 APPEND(log10, FLOAT_NAME_EXT)
  40
  41
  42 int
  43 APPEND (FUNC_PREFIX, fcvt_r) (value, ndigit, decpt, sign, buf, len)
  44      FLOAT_TYPE value;
  45      int ndigit, *decpt, *sign;
  46      char *buf;
  47      size_t len;
  48 {
  49   int n, i;
  50
  51   if (buf == NULL)
  52     {
  53       __set_errno (EINVAL);
  54       return -1;
  55     }
  56
  57   *sign = value < 0.0;
  58   if (*sign)
  59     value = - value;
  60
  61   n = snprintf (buf, len, "%.*" FLOAT_FMT_FLAG "f", ndigit, value);
  62   if (n < 0)
  63     return -1;
  64
  65   i = 0;
  66   while (i < n && isdigit (buf[i]))
  67     ++i;
  68   *decpt = i;
  69   do
  70     ++i;
  71   while (! isdigit (buf[i]));
  72   memmove (&buf[i - *decpt], buf, n - (i - *decpt));
  73
  74   return 0;
  75 }
  76
  77 #define weak_extern2(name) weak_extern (name)
  78 weak_extern2 (FLOOR) weak_extern2 (LOG10) weak_extern2 (FABS)
  79
  80 int
  81 APPEND (FUNC_PREFIX, ecvt_r) (value, ndigit, decpt, sign, buf, len)
  82      FLOAT_TYPE value;
  83      int ndigit, *decpt, *sign;
  84      char *buf;
  85      size_t len;
  86 {
  87   FLOAT_TYPE (*log10_function) (FLOAT_TYPE) = &LOG10;
  88
  89   if (log10_function)
  90     {
  91       /* Use the reasonable code if -lm is included.  */
  92       ndigit -= (int) FLOOR (LOG10 (FABS (value)));
  93       if (ndigit < 0)
  94         ndigit = 0;
  95     }
  96   else
  97     {
  98       /* Slow code that doesn't require -lm functions.  */
  99       FLOAT_TYPE d;
 100       for (d = value < 0.0 ? - value : value;
 101            ndigit > 0 && d >= 10.0;
 102            d *= 0.1)
 103         --ndigit;
 104     }
 105
 106   return APPEND (FUNC_PREFIX, fcvt_r) (value, ndigit, decpt, sign, buf, len);
 107 }