glibc/misc/efgcvt.c

/* Compatibility functions for floating point formatting.
   Copyright (C) 1995-2019 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C 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 2.1 of the License, or (at your option) any later version.

   The GNU C 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 C Library; if not, see
   <https://www.gnu.org/licenses/>.  */

#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/param.h>
#include <float.h>
#include <libc-lock.h>
#include <math_ldbl_opt.h>

#ifndef FLOAT_TYPE
# define FLOAT_TYPE double
# define FUNC_PREFIX
# define FLOAT_FMT_FLAG
/* Actually we have to write (DBL_DIG + log10 (DBL_MAX_10_EXP)) but we
   don't have log10 available in the preprocessor.  */
# define MAXDIG (NDIGIT_MAX + 3)
# define FCVT_MAXDIG (DBL_MAX_10_EXP + MAXDIG)
# if DBL_MANT_DIG == 53
#  define NDIGIT_MAX 17
# elif DBL_MANT_DIG == 24
#  define NDIGIT_MAX 9
# elif DBL_MANT_DIG == 56
#  define NDIGIT_MAX 18
# else
/* See IEEE 854 5.6, table 2 for this formula.  Unfortunately we need a
   compile time constant here, so we cannot use it.  */
#  error "NDIGIT_MAX must be precomputed"
#  define NDIGIT_MAX (lrint (ceil (M_LN2 / M_LN10 * DBL_MANT_DIG + 1.0)))
# endif
#else
# define LONG_DOUBLE_CVT
#endif

#define APPEND(a, b) APPEND2 (a, b)
#define APPEND2(a, b) a##b
#define __APPEND(a, b) __APPEND2 (a, b)
#define __APPEND2(a, b) __##a##b


#define FCVT_BUFFER APPEND (FUNC_PREFIX, fcvt_buffer)
#define FCVT_BUFPTR APPEND (FUNC_PREFIX, fcvt_bufptr)
#define ECVT_BUFFER APPEND (FUNC_PREFIX, ecvt_buffer)


static char FCVT_BUFFER[MAXDIG];
static char ECVT_BUFFER[MAXDIG];
libc_freeres_ptr (static char *FCVT_BUFPTR);

char *
__APPEND (FUNC_PREFIX, fcvt) (FLOAT_TYPE value, int ndigit, int *decpt,
			      int *sign)
{
  if (FCVT_BUFPTR == NULL)
    {
      if (__APPEND (FUNC_PREFIX, fcvt_r) (value, ndigit, decpt, sign,
					  FCVT_BUFFER, MAXDIG) != -1)
	return FCVT_BUFFER;

      FCVT_BUFPTR = (char *) malloc (FCVT_MAXDIG);
      if (FCVT_BUFPTR == NULL)
	return FCVT_BUFFER;
    }

  (void) __APPEND (FUNC_PREFIX, fcvt_r) (value, ndigit, decpt, sign,
					 FCVT_BUFPTR, FCVT_MAXDIG);

  return FCVT_BUFPTR;
}


char *
__APPEND (FUNC_PREFIX, ecvt) (FLOAT_TYPE value, int ndigit, int *decpt,
			      int *sign)
{
  (void) __APPEND (FUNC_PREFIX, ecvt_r) (value, ndigit, decpt, sign,
					 ECVT_BUFFER, MAXDIG);

  return ECVT_BUFFER;
}

char *
__APPEND (FUNC_PREFIX, gcvt) (FLOAT_TYPE value, int ndigit, char *buf)
{
  sprintf (buf, "%.*" FLOAT_FMT_FLAG "g", MIN (ndigit, NDIGIT_MAX), value);
  return buf;
}

#if LONG_DOUBLE_COMPAT (libc, GLIBC_2_0)
# ifdef LONG_DOUBLE_CVT
#  define cvt_symbol(symbol) \
  cvt_symbol_1 (libc, __APPEND (FUNC_PREFIX, symbol), \
	      APPEND (FUNC_PREFIX, symbol), GLIBC_2_4)
#  define cvt_symbol_1(lib, local, symbol, version) \
    versioned_symbol (lib, local, symbol, version)
# else
#  define cvt_symbol(symbol) \
  cvt_symbol_1 (libc, __APPEND (FUNC_PREFIX, symbol), \
	      APPEND (q, symbol), GLIBC_2_0); \
  strong_alias (__APPEND (FUNC_PREFIX, symbol), APPEND (FUNC_PREFIX, symbol))
#  define cvt_symbol_1(lib, local, symbol, version) \
  compat_symbol (lib, local, symbol, version)
# endif
#else
# define cvt_symbol(symbol) \
  strong_alias (__APPEND (FUNC_PREFIX, symbol), APPEND (FUNC_PREFIX, symbol))
#endif
cvt_symbol(fcvt);
cvt_symbol(ecvt);
cvt_symbol(gcvt);