gcc/m2/mc-boot-ch/Gldtoa.cc

   1 /* Gldtoa.cc provides access to long double string conversion.
   2
   3 Copyright (C) 2016-2024 Free Software Foundation, Inc.
   4 Contributed by Gaius Mulley <gaius@glam.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 You should have received a copy of the GNU General Public License
  19 along with GNU Modula-2; see the file COPYING3.  If not see
  20 <http://www.gnu.org/licenses/>.  */
  21
  22 #include "config.h"
  23 #include "system.h"
  24
  25 #include "gm2-libs-host.h"
  26
  27 #ifdef __cplusplus
  28 extern "C" {
  29 #endif
  30
  31 #define MAX_FP_DIGITS 500
  32
  33 typedef enum Mode { maxsignicant, decimaldigits } Mode;
  34
  35 extern int dtoa_calcmaxsig (char *p, int ndigits);
  36 extern int dtoa_calcdecimal (char *p, int str_size, int ndigits);
  37 extern int dtoa_calcsign (char *p, int str_size);
  38
  39 /* maxsignicant: return a string containing max(1,ndigits)
  40    significant digits.  The return string contains the string
  41    produced by snprintf.  decimaldigits: return a string produced by
  42    fcvt.  The string will contain ndigits past the decimal point
  43    (ndigits may be negative).  */
  44
  45 long double
  46 ldtoa_strtold (const char *s, int *error)
  47 {
  48   char *endp;
  49   long double d;
  50
  51   errno = 0;
  52 #if defined(HAVE_STRTOLD)
  53   d = strtold (s, &endp);
  54 #else
  55   /* fall back to using strtod.  */
  56   d = (long double)strtod (s, &endp);
  57 #endif
  58   if (endp != NULL && (*endp == '\0'))
  59     *error = (errno != 0);
  60   else
  61     *error = TRUE;
  62   return d;
  63 }
  64
  65 char *
  66 ldtoa_ldtoa (long double d, int mode, int ndigits, int *decpt, int *sign)
  67 {
  68   char format[50];
  69   char *p;
  70   int r;
  71   switch (mode)
  72     {
  73
  74     case maxsignicant:
  75       ndigits += 20; /* enough for exponent.  */
  76       p = (char *)malloc (ndigits);
  77       snprintf (format, 50, "%s%d%s", "%.", ndigits - 20, "LE");
  78       snprintf (p, ndigits, format, d);
  79       *sign = dtoa_calcsign (p, ndigits);
  80       *decpt = dtoa_calcmaxsig (p, ndigits);
  81       return p;
  82     case decimaldigits:
  83       p = (char *)malloc (MAX_FP_DIGITS + 20);
  84       snprintf (format, 50, "%s%d%s", "%.", MAX_FP_DIGITS, "LE");
  85       snprintf (p, MAX_FP_DIGITS + 20, format, d);
  86       *sign = dtoa_calcsign (p, MAX_FP_DIGITS + 20);
  87       *decpt = dtoa_calcdecimal (p, MAX_FP_DIGITS + 20, ndigits);
  88       return p;
  89     default:
  90       abort ();
  91     }
  92 }
  93
  94 /* GNU Modula-2 hooks */
  95
  96 void
  97 _M2_ldtoa_init (void)
  98 {
  99 }
 100
 101 void
 102 _M2_ldtoa_fini (void)
 103 {
 104 }
 105 #   ifdef __cplusplus
 106 }
 107 #   endif