gcc/m2/gm2-libs-ch/ldtoa.cc

   1 /* ldtoa.c provide long double floating point string conversion routines.
   2
   3 Copyright (C) 2009-2023 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 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 #include "config.h"
  28 #include "system.h"
  29 #include "ansidecl.h"
  30
  31 #include "gm2-libs-host.h"
  32 #include "m2rts.h"
  33
  34 #   ifdef __cplusplus
  35 extern "C" {
  36 #   endif
  37
  38 #define MAX_FP_DIGITS 500
  39
  40 typedef enum Mode { maxsignicant, decimaldigits } Mode;
  41
  42 extern int dtoa_calcmaxsig (char *p, int ndigits);
  43 extern int dtoa_calcdecimal (char *p, int str_size, int ndigits);
  44 extern int dtoa_calcsign (char *p, int str_size);
  45
  46 /* maxsignicant: return a string containing max(1,ndigits)
  47    significant digits.  The return string contains the string
  48    produced by snprintf.  decimaldigits: return a string produced by
  49    fcvt.  The string will contain ndigits past the decimal point
  50    (ndigits may be negative).  */
  51
  52 long double
  53 ldtoa_strtold (const char *s, int *error)
  54 {
  55   char *endp;
  56   long double d;
  57
  58   errno = 0;
  59 #if defined(HAVE_STRTOLD)
  60   d = strtold (s, &endp);
  61 #else
  62   /* fall back to using strtod.  */
  63   d = (long double)strtod (s, &endp);
  64 #endif
  65   if (endp != NULL && (*endp == '\0'))
  66     *error = (errno != 0);
  67   else
  68     *error = TRUE;
  69   return d;
  70 }
  71
  72 char *
  73 ldtoa_ldtoa (long double d, int mode, int ndigits, int *decpt, int *sign)
  74 {
  75   char format[50];
  76   char *p;
  77   int r;
  78   switch (mode)
  79     {
  80
  81     case maxsignicant:
  82       ndigits += 20; /* enough for exponent.  */
  83       p = (char *) malloc (ndigits);
  84       snprintf (format, 50, "%s%d%s", "%.", ndigits - 20, "LE");
  85       snprintf (p, ndigits, format, d);
  86       *sign = dtoa_calcsign (p, ndigits);
  87       *decpt = dtoa_calcmaxsig (p, ndigits);
  88       return p;
  89     case decimaldigits:
  90       p = (char *) malloc (MAX_FP_DIGITS + 20);
  91       snprintf (format, 50, "%s%d%s", "%.", MAX_FP_DIGITS, "LE");
  92       snprintf (p, MAX_FP_DIGITS + 20, format, d);
  93       *sign = dtoa_calcsign (p, MAX_FP_DIGITS + 20);
  94       *decpt = dtoa_calcdecimal (p, MAX_FP_DIGITS + 20, ndigits);
  95       return p;
  96     default:
  97       abort ();
  98     }
  99 }
 100
 101 /* GNU Modula-2 hooks */
 102
 103 void
 104 _M2_ldtoa_init (int, char **, char **)
 105 {
 106 }
 107
 108 void
 109 _M2_ldtoa_finish (int, char **, char **)
 110 {
 111 }
 112
 113 void
 114 _M2_ldtoa_dep (void)
 115 {
 116 }
 117
 118 #   ifdef __cplusplus
 119 }
 120
 121 extern "C" void __attribute__((__constructor__))
 122 _M2_ldtoa_ctor (void)
 123 {
 124   M2RTS_RegisterModule ("ldtoa", _M2_ldtoa_init, _M2_ldtoa_finish,
 125                         _M2_ldtoa_dep);
 126 }
 127
 128 #else
 129 void
 130 _M2_ldtoa_ctor (void)
 131 {
 132 }
 133
 134 #   endif