1: /* Compatibility functions for floating point formatting, reentrant versions.
    2:    Copyright (C) 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2004, 2006
    3:    Free Software Foundation, Inc.
    4:    This file is part of the GNU C Library.
    5: 
    6:    The GNU C Library is free software; you can redistribute it and/or
    7:    modify it under the terms of the GNU Lesser General Public
    8:    License as published by the Free Software Foundation; either
    9:    version 2.1 of the License, or (at your option) any later version.
   10: 
   11:    The GNU C Library is distributed in the hope that it will be useful,
   12:    but WITHOUT ANY WARRANTY; without even the implied warranty of
   13:    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   14:    Lesser General Public License for more details.
   15: 
   16:    You should have received a copy of the GNU Lesser General Public
   17:    License along with the GNU C Library; if not, write to the Free
   18:    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   19:    02111-1307 USA.  */
   20: 
   21: #include <errno.h>
   22: #include <float.h>
   23: #include <stdio.h>
   24: #include <string.h>
   25: #include <ctype.h>
   26: #include <math.h>
   27: #include <stdlib.h>
   28: #include <sys/param.h>
   29: #include <math_ldbl_opt.h>
   30: 
   31: #ifndef FLOAT_TYPE
   32: # define FLOAT_TYPE double
   33: # define FUNC_PREFIX
   34: # define FLOAT_FMT_FLAG
   35: # define FLOAT_NAME_EXT
   36: # define FLOAT_MIN_10_EXP DBL_MIN_10_EXP
   37: # if DBL_MANT_DIG == 53
   38: #  define NDIGIT_MAX 17
   39: # elif DBL_MANT_DIG == 24
   40: #  define NDIGIT_MAX 9
   41: # elif DBL_MANT_DIG == 56
   42: #  define NDIGIT_MAX 18
   43: # else
   44: /* See IEEE 854 5.6, table 2 for this formula.  Unfortunately we need a
   45:    compile time constant here, so we cannot use it.  */
   46: #  error "NDIGIT_MAX must be precomputed"
   47: #  define NDIGIT_MAX (lrint (ceil (M_LN2 / M_LN10 * DBL_MANT_DIG + 1.0)))
   48: # endif
   49: # if DBL_MIN_10_EXP == -37
   50: #  define FLOAT_MIN_10_NORM     1.0e-37
   51: # elif DBL_MIN_10_EXP == -307
   52: #  define FLOAT_MIN_10_NORM     1.0e-307
   53: # elif DBL_MIN_10_EXP == -4931
   54: #  define FLOAT_MIN_10_NORM     1.0e-4931
   55: # else
   56: /* libc can't depend on libm.  */
   57: #  error "FLOAT_MIN_10_NORM must be precomputed"
   58: #  define FLOAT_MIN_10_NORM     exp10 (DBL_MIN_10_EXP)
   59: # endif
   60: #else
   61: # define LONG_DOUBLE_CVT
   62: #endif
   63: 
   64: #define APPEND(a, b) APPEND2 (a, b)
   65: #define APPEND2(a, b) a##b
   66: #define __APPEND(a, b) __APPEND2 (a, b)
   67: #define __APPEND2(a, b) __##a##b
   68: 
   69: #define FLOOR APPEND(floor, FLOAT_NAME_EXT)
   70: #define FABS APPEND(fabs, FLOAT_NAME_EXT)
   71: #define LOG10 APPEND(log10, FLOAT_NAME_EXT)
   72: #define EXP APPEND(exp, FLOAT_NAME_EXT)
   73: 
   74: 
   75: int
   76: __APPEND (FUNC_PREFIX, fcvt_r) (value, ndigit, decpt, sign, buf, len)
   77:      FLOAT_TYPE value;
   78:      int ndigit, *decpt, *sign;
   79:      char *buf;
   80:      size_t len;
   81: {
   82:   ssize_t n;
   83:   ssize_t i;
   84:   int left;
   85: 
   86:   if (buf == NULL)
   87:     {
   88:       __set_errno (EINVAL);
   89:       return -1;
   90:     }
   91: 
   92:   left = 0;
   93:   if (isfinite (value))
   94:     {
   95:       *sign = signbit (value) != 0;
   96:       if (*sign)
   97:         value = -value;
   98: 
   99:       if (ndigit < 0)
  100:         {
  101:           /* Rounding to the left of the decimal point.  */
  102:           while (ndigit < 0)
  103:             {
  104:               FLOAT_TYPE new_value = value * 0.1;
  105: 
  106:               if (new_value < 1.0)
  107:                 {
  108:                   ndigit = 0;
  109:                   break;
  110:                 }
  111: 
  112:               value = new_value;
  113:               ++left;
  114:               ++ndigit;
  115:             }
  116:         }
  117:     }
  118:   else
  119:     /* Value is Inf or NaN.  */
  120:     *sign = 0;
  121: 
  122:   n = __snprintf (buf, len, "%.*" FLOAT_FMT_FLAG "f", MIN (ndigit, NDIGIT_MAX),
  123:                   value);
  124:   /* Check for a too small buffer.  */
  125:   if (n >= (ssize_t) len)
  126:     return -1;
  127: 
  128:   i = 0;
  129:   while (i < n && isdigit (buf[i]))
  130:     ++i;
  131:   *decpt = i;
  132: 
  133:   if (i == 0)
  134:     /* Value is Inf or NaN.  */
  135:     return 0;
  136: 
  137:   if (i < n)
  138:     {
  139:       do
  140:         ++i;
  141:       while (i < n && !isdigit (buf[i]));
  142: 
  143:       if (*decpt == 1 && buf[0] == '0' && value != 0.0)
  144:         {
  145:           /* We must not have leading zeroes.  Strip them all out and
  146:              adjust *DECPT if necessary.  */
  147:           --*decpt;
  148:           while (i < n && buf[i] == '0')
  149:             {
  150:               --*decpt;
  151:               ++i;
  152:             }
  153:         }
  154: 
  155:       memmove (&buf[MAX (*decpt, 0)], &buf[i], n - i);
  156:       buf[n - (i - MAX (*decpt, 0))] = '\0';
  157:     }
  158: 
  159:   if (left)
  160:     {
  161:       *decpt += left;
  162:       if ((ssize_t) --len > n)
  163:         {
  164:           while (left-- > 0 && n < (ssize_t) len)
  165:             buf[n++] = '0';
  166:           buf[n] = '\0';
  167:         }
  168:     }
  169: 
  170:   return 0;
  171: }
  172: 
  173: int
  174: __APPEND (FUNC_PREFIX, ecvt_r) (value, ndigit, decpt, sign, buf, len)
  175:      FLOAT_TYPE value;
  176:      int ndigit, *decpt, *sign;
  177:      char *buf;
  178:      size_t len;
  179: {
  180:   int exponent = 0;
  181: 
  182:   if (isfinite (value) && value != 0.0)
  183:     {
  184:       /* Slow code that doesn't require -lm functions.  */
  185:       FLOAT_TYPE d;
  186:       FLOAT_TYPE f = 1.0;
  187:       if (value < 0.0)
  188:         d = -value;
  189:       else
  190:         d = value;
  191:       /* For denormalized numbers the d < 1.0 case below won't work,
  192:          as f can overflow to +Inf.  */
  193:       if (d < FLOAT_MIN_10_NORM)
  194:         {
  195:           value /= FLOAT_MIN_10_NORM;
  196:           if (value < 0.0)
  197:             d = -value;
  198:           else
  199:             d = value;
  200:           exponent += FLOAT_MIN_10_EXP;
  201:         }
  202:       if (d < 1.0)
  203:         {
  204:           do
  205:             {
  206:               f *= 10.0;
  207:               --exponent;
  208:             }
  209:           while (d * f < 1.0);
  210: 
  211:           value *= f;
  212:         }
  213:       else if (d >= 10.0)
  214:         {
  215:           do
  216:             {
  217:               f *= 10;
  218:               ++exponent;
  219:             }
  220:           while (d >= f * 10.0);
  221: 
  222:           value /= f;
  223:         }
  224:     }
  225:   else if (value == 0.0)
  226:     /* SUSv2 leaves it unspecified whether *DECPT is 0 or 1 for 0.0.
  227:        This could be changed to -1 if we want to return 0.  */
  228:     exponent = 0;
  229: 
  230:   if (ndigit <= 0 && len > 0)
  231:     {
  232:       buf[0] = '\0';
  233:       *decpt = 1;
  234:       *sign = isfinite (value) ? signbit (value) != 0 : 0;
  235:     }
  236:   else
  237:     if (__APPEND (FUNC_PREFIX, fcvt_r) (value, MIN (ndigit, NDIGIT_MAX) - 1,
  238:                                         decpt, sign, buf, len))
  239:       return -1;
  240: 
  241:   *decpt += exponent;
  242:   return 0;
  243: }
  244: 
  245: #if LONG_DOUBLE_COMPAT (libc, GLIBC_2_0)
  246: # ifdef LONG_DOUBLE_CVT
  247: #  define cvt_symbol(symbol) \
  248:   cvt_symbol_1 (libc, __APPEND (FUNC_PREFIX, symbol), \
  249:               APPEND (FUNC_PREFIX, symbol), GLIBC_2_4)
  250: #  define cvt_symbol_1(lib, local, symbol, version) \
  251:     versioned_symbol (lib, local, symbol, version)
  252: # else
  253: #  define cvt_symbol(symbol) \
  254:   cvt_symbol_1 (libc, __APPEND (FUNC_PREFIX, symbol), \
  255:               APPEND (q, symbol), GLIBC_2_0); \
  256:   strong_alias (__APPEND (FUNC_PREFIX, symbol), APPEND (FUNC_PREFIX, symbol))
  257: #  define cvt_symbol_1(lib, local, symbol, version) \
  258:   compat_symbol (lib, local, symbol, version)
  259: # endif
  260: #else
  261: # define cvt_symbol(symbol) \
  262:   strong_alias (__APPEND (FUNC_PREFIX, symbol), APPEND (FUNC_PREFIX, symbol))
  263: #endif
  264: cvt_symbol(fcvt_r);
  265: cvt_symbol(ecvt_r);