libgm2/libm2pim/ldtoa.cc

   1 /* ldtoa.c convert long double to ascii and visa versa.
   2
   3 Copyright (C) 2009-2022 Free Software Foundation, Inc.
   4 Contributed by Gaius Mulley <gaius.mulley@southwales.ac.uk>.
   5
   6 This file is part of GNU Modula-2.
   7
   8 GNU Modula-2 is free software; you can redistribute it and/or modify
   9 it under the terms of the GNU General Public License as published by
  10 the Free Software Foundation; either version 3, or (at your option)
  11 any later version.
  12
  13 GNU Modula-2 is distributed in the hope that it will be useful, but
  14 WITHOUT ANY WARRANTY; without even the implied warranty of
  15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16 General Public License for more details.
  17
  18 Under Section 7 of GPL version 3, you are granted additional
  19 permissions described in the GCC Runtime Library Exception, version
  20 3.1, as published by the Free Software Foundation.
  21
  22 You should have received a copy of the GNU General Public License and
  23 a copy of the GCC Runtime Library Exception along with this program;
  24 see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  25 <http://www.gnu.org/licenses/>.  */
  26
  27 #define GM2
  28
  29 #include <config.h>
  30 #include <m2rts.h>
  31
  32 #define EXPORT(FUNC) m2pim ## _ldtoa_ ## FUNC
  33 #define IMPORT(MODULE,FUNC) m2pim ## _ ## MODULE ## _ ## FUNC
  34 #define M2EXPORT(FUNC) m2pim ## _M2_ldtoa_ ## FUNC
  35 #define M2LIBNAME "m2pim"
  36
  37 #if defined(HAVE_STRINGS)
  38 #include <strings.h>
  39 #endif
  40
  41 #if defined(HAVE_STRING)
  42 #include <string.h>
  43 #endif
  44
  45 #if defined(HAVE_STDDEF_H)
  46 /* Obtain a definition for NULL.  */
  47 #include <stddef.h>
  48 #endif
  49
  50 #if defined(HAVE_STDIO_H)
  51 /* Obtain a definition for NULL.  */
  52 #include <stdio.h>
  53 #endif
  54
  55 #if defined(HAVE_TIME_H)
  56 /* Obtain a definition for NULL.  */
  57 #include <time.h>
  58 #endif
  59
  60 #if defined(HAVE_STRING_H)
  61 /* Obtain a definition for NULL.  */
  62 #include <string.h>
  63 #endif
  64
  65 #if defined(HAVE_WCHAR_H)
  66 /* Obtain a definition for NULL.  */
  67 #include <wchar.h>
  68 #endif
  69
  70 #if defined(HAVE_STDLIB_H)
  71 #if !defined(_ISOC99_SOURCE)
  72 #define _ISOC99_SOURCE
  73 #endif
  74 #include <stdlib.h>
  75 #endif
  76
  77 #if defined(HAVE_ERRNO_H)
  78 #include <errno.h>
  79 #endif
  80
  81 #if defined(HAVE_SYS_ERRNO_H)
  82 #include <sys/errno.h>
  83 #endif
  84
  85 #if defined(HAVE_STDLIB_H)
  86 /* Obtain a prototype for free and malloc.  */
  87 #include <stdlib.h>
  88 #endif
  89
  90 #if !defined(NULL)
  91 #define NULL (void *)0
  92 #endif
  93
  94 #define MAX_FP_DIGITS 500
  95
  96 typedef enum Mode { maxsignicant, decimaldigits } Mode;
  97
  98 extern "C" int IMPORT(dtoa,calcmaxsig) (char *p, int ndigits);
  99 extern "C" int IMPORT(dtoa,calcdecimal) (char *p, int str_size, int ndigits);
 100 extern "C" int IMPORT(dtoa,calcsign) (char *p, int str_size);
 101
 102 /* maxsignicant return a string containing max(1,ndigits) significant
 103    digits.  The return string contains the string produced by snprintf.
 104
 105    decimaldigits: return a string produced by fcvt.  The string will
 106    contain ndigits past the decimal point (ndigits may be negative).  */
 107
 108 extern "C" long double
 109 EXPORT(strtold) (const char *s, bool *error)
 110 {
 111   char *endp;
 112   long double d;
 113
 114 #if defined(HAVE_ERRNO_H)
 115   errno = 0;
 116 #endif
 117 #if defined(HAVE_STRTOLD)
 118   d = strtold (s, &endp);
 119 #else
 120   /* Fall back to using strtod.  */
 121   d = (long double)strtod (s, &endp);
 122 #endif
 123   if (endp != NULL && (*endp == '\0'))
 124 #if defined(HAVE_ERRNO_H)
 125     *error = (errno != 0);
 126 #else
 127     *error = false;
 128 #endif
 129   else
 130     *error = true;
 131   return d;
 132 }
 133
 134 extern "C" char *
 135 EXPORT(ldtoa) (long double d, int mode, int ndigits, int *decpt, bool *sign)
 136 {
 137   char format[50];
 138   char *p;
 139   int r;
 140   switch (mode)
 141     {
 142
 143     case maxsignicant:
 144       ndigits += 20; /* Enough for exponent.  */
 145       p = (char *) malloc (ndigits);
 146       snprintf (format, 50, "%s%d%s", "%.", ndigits - 20, "LE");
 147       snprintf (p, ndigits, format, d);
 148       *sign = IMPORT(dtoa,calcsign) (p, ndigits);
 149       *decpt = IMPORT(dtoa,calcmaxsig) (p, ndigits);
 150       return p;
 151     case decimaldigits:
 152       p = (char *) malloc (MAX_FP_DIGITS + 20);
 153       snprintf (format, 50, "%s%d%s", "%.", MAX_FP_DIGITS, "LE");
 154       snprintf (p, MAX_FP_DIGITS + 20, format, d);
 155       *sign = IMPORT(dtoa,calcsign) (p, MAX_FP_DIGITS + 20);
 156       *decpt = IMPORT(dtoa,calcdecimal) (p, MAX_FP_DIGITS + 20, ndigits);
 157       return p;
 158     default:
 159       abort ();
 160     }
 161 }
 162
 163 #if defined(GM2)
 164 /* GNU Modula-2 linking hooks.  */
 165
 166 extern "C" void
 167 M2EXPORT(init) (int, char **, char **)
 168 {
 169 }
 170
 171 extern "C" void
 172 M2EXPORT(fini) (int, char **, char **)
 173 {
 174 }
 175
 176 extern "C" void
 177 M2EXPORT(dep) (void)
 178 {
 179 }
 180
 181 extern "C" void __attribute__((__constructor__))
 182 M2EXPORT(ctor) (void)
 183 {
 184   m2pim_M2RTS_RegisterModule ("ldtoa", M2LIBNAME,
 185                               M2EXPORT(init), M2EXPORT(fini),
 186                               M2EXPORT(dep));
 187 }
 188 #endif