misc/efgcvt.c

   1 /* Compatibility functions for floating point formatting.
   2    Copyright (C) 1995-2015 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 Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the 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    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <math.h>
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <sys/param.h>
  23 #include <float.h>
  24 #include <bits/libc-lock.h>
  25 #include <math_ldbl_opt.h>
  26
  27 #ifndef FLOAT_TYPE
  28 # define FLOAT_TYPE double
  29 # define FUNC_PREFIX
  30 # define FLOAT_FMT_FLAG
  31 /* Actually we have to write (DBL_DIG + log10 (DBL_MAX_10_EXP)) but we
  32    don't have log10 available in the preprocessor.  */
  33 # define MAXDIG (NDIGIT_MAX + 3)
  34 # define FCVT_MAXDIG (DBL_MAX_10_EXP + MAXDIG)
  35 # if DBL_MANT_DIG == 53
  36 #  define NDIGIT_MAX 17
  37 # elif DBL_MANT_DIG == 24
  38 #  define NDIGIT_MAX 9
  39 # elif DBL_MANT_DIG == 56
  40 #  define NDIGIT_MAX 18
  41 # else
  42 /* See IEEE 854 5.6, table 2 for this formula.  Unfortunately we need a
  43    compile time constant here, so we cannot use it.  */
  44 #  error "NDIGIT_MAX must be precomputed"
  45 #  define NDIGIT_MAX (lrint (ceil (M_LN2 / M_LN10 * DBL_MANT_DIG + 1.0)))
  46 # endif
  47 #else
  48 # define LONG_DOUBLE_CVT
  49 #endif
  50
  51 #define APPEND(a, b) APPEND2 (a, b)
  52 #define APPEND2(a, b) a##b
  53 #define __APPEND(a, b) __APPEND2 (a, b)
  54 #define __APPEND2(a, b) __##a##b
  55
  56
  57 #define FCVT_BUFFER APPEND (FUNC_PREFIX, fcvt_buffer)
  58 #define FCVT_BUFPTR APPEND (FUNC_PREFIX, fcvt_bufptr)
  59 #define ECVT_BUFFER APPEND (FUNC_PREFIX, ecvt_buffer)
  60
  61
  62 static char FCVT_BUFFER[MAXDIG];
  63 static char ECVT_BUFFER[MAXDIG];
  64 libc_freeres_ptr (static char *FCVT_BUFPTR);
  65
  66 char *
  67 __APPEND (FUNC_PREFIX, fcvt) (value, ndigit, decpt, sign)
  68      FLOAT_TYPE value;
  69      int ndigit, *decpt, *sign;
  70 {
  71   if (FCVT_BUFPTR == NULL)
  72     {
  73       if (__APPEND (FUNC_PREFIX, fcvt_r) (value, ndigit, decpt, sign,
  74                                           FCVT_BUFFER, MAXDIG) != -1)
  75         return FCVT_BUFFER;
  76
  77       FCVT_BUFPTR = (char *) malloc (FCVT_MAXDIG);
  78       if (FCVT_BUFPTR == NULL)
  79         return FCVT_BUFFER;
  80     }
  81
  82   (void) __APPEND (FUNC_PREFIX, fcvt_r) (value, ndigit, decpt, sign,
  83                                          FCVT_BUFPTR, FCVT_MAXDIG);
  84
  85   return FCVT_BUFPTR;
  86 }
  87
  88
  89 char *
  90 __APPEND (FUNC_PREFIX, ecvt) (value, ndigit, decpt, sign)
  91      FLOAT_TYPE value;
  92      int ndigit, *decpt, *sign;
  93 {
  94   (void) __APPEND (FUNC_PREFIX, ecvt_r) (value, ndigit, decpt, sign,
  95                                          ECVT_BUFFER, MAXDIG);
  96
  97   return ECVT_BUFFER;
  98 }
  99
 100 char *
 101 __APPEND (FUNC_PREFIX, gcvt) (value, ndigit, buf)
 102      FLOAT_TYPE value;
 103      int ndigit;
 104      char *buf;
 105 {
 106   sprintf (buf, "%.*" FLOAT_FMT_FLAG "g", MIN (ndigit, NDIGIT_MAX), value);
 107   return buf;
 108 }
 109
 110 #if LONG_DOUBLE_COMPAT (libc, GLIBC_2_0)
 111 # ifdef LONG_DOUBLE_CVT
 112 #  define cvt_symbol(symbol) \
 113   cvt_symbol_1 (libc, __APPEND (FUNC_PREFIX, symbol), \
 114               APPEND (FUNC_PREFIX, symbol), GLIBC_2_4)
 115 #  define cvt_symbol_1(lib, local, symbol, version) \
 116     versioned_symbol (lib, local, symbol, version)
 117 # else
 118 #  define cvt_symbol(symbol) \
 119   cvt_symbol_1 (libc, __APPEND (FUNC_PREFIX, symbol), \
 120               APPEND (q, symbol), GLIBC_2_0); \
 121   strong_alias (__APPEND (FUNC_PREFIX, symbol), APPEND (FUNC_PREFIX, symbol))
 122 #  define cvt_symbol_1(lib, local, symbol, version) \
 123   compat_symbol (lib, local, symbol, version)
 124 # endif
 125 #else
 126 # define cvt_symbol(symbol) \
 127   strong_alias (__APPEND (FUNC_PREFIX, symbol), APPEND (FUNC_PREFIX, symbol))
 128 #endif
 129 cvt_symbol(fcvt);
 130 cvt_symbol(ecvt);
 131 cvt_symbol(gcvt);