contrib/gdtoa/g__fmt.c

   1 /****************************************************************
   2
   3 The author of this software is David M. Gay.
   4
   5 Copyright (C) 1998 by Lucent Technologies
   6 All Rights Reserved
   7
   8 Permission to use, copy, modify, and distribute this software and
   9 its documentation for any purpose and without fee is hereby
  10 granted, provided that the above copyright notice appear in all
  11 copies and that both that the copyright notice and this
  12 permission notice and warranty disclaimer appear in supporting
  13 documentation, and that the name of Lucent or any of its entities
  14 not be used in advertising or publicity pertaining to
  15 distribution of the software without specific, written prior
  16 permission.
  17
  18 LUCENT DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
  19 INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS.
  20 IN NO EVENT SHALL LUCENT OR ANY OF ITS ENTITIES BE LIABLE FOR ANY
  21 SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  22 WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER
  23 IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
  24 ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
  25 THIS SOFTWARE.
  26
  27 ****************************************************************/
  28
  29 /* Please send bug reports to David M. Gay (dmg at acm dot org,
  30  * with " at " changed at "@" and " dot " changed to ".").      */
  31
  32 #include "gdtoaimp.h"
  33
  34 #ifdef USE_LOCALE
  35 #include "locale.h"
  36 #endif
  37
  38  char *
  39 #ifdef KR_headers
  40 g__fmt(b, s, se, decpt, sign, blen) char *b; char *s; char *se; int decpt; ULong sign; size_t blen;
  41 #else
  42 g__fmt(char *b, char *s, char *se, int decpt, ULong sign, size_t blen)
  43 #endif
  44 {
  45         int i, j, k;
  46         char *be, *s0;
  47         size_t len;
  48 #ifdef USE_LOCALE
  49 #ifdef NO_LOCALE_CACHE
  50         char *decimalpoint = localeconv()->decimal_point;
  51         size_t dlen = strlen(decimalpoint);
  52 #else
  53         char *decimalpoint;
  54         static char *decimalpoint_cache;
  55         static size_t dlen;
  56         if (!(s0 = decimalpoint_cache)) {
  57                 s0 = localeconv()->decimal_point;
  58                 dlen = strlen(s0);
  59                 if ((decimalpoint_cache = (char*)malloc(strlen(s0) + 1))) {
  60                         strcpy(decimalpoint_cache, s0);
  61                         s0 = decimalpoint_cache;
  62                         }
  63                 }
  64         decimalpoint = s0;
  65 #endif
  66 #else
  67 #define dlen 0
  68 #endif
  69         s0 = s;
  70         len = (se-s) + dlen + 6; /* 6 = sign + e+dd + trailing null */
  71         if (blen < len)
  72                 goto ret0;
  73         be = b + blen - 1;
  74         if (sign)
  75                 *b++ = '-';
  76         if (decpt <= -4 || decpt > se - s + 5) {
  77                 *b++ = *s++;
  78                 if (*s) {
  79 #ifdef USE_LOCALE
  80                         while((*b = *decimalpoint++))
  81                                 ++b;
  82 #else
  83                         *b++ = '.';
  84 #endif
  85                         while((*b = *s++) !=0)
  86                                 b++;
  87                         }
  88                 *b++ = 'e';
  89                 /* sprintf(b, "%+.2d", decpt - 1); */
  90                 if (--decpt < 0) {
  91                         *b++ = '-';
  92                         decpt = -decpt;
  93                         }
  94                 else
  95                         *b++ = '+';
  96                 for(j = 2, k = 10; 10*k <= decpt; j++, k *= 10){}
  97                 for(;;) {
  98                         i = decpt / k;
  99                         if (b >= be)
 100                                 goto ret0;
 101                         *b++ = i + '0';
 102                         if (--j <= 0)
 103                                 break;
 104                         decpt -= i*k;
 105                         decpt *= 10;
 106                         }
 107                 *b = 0;
 108                 }
 109         else if (decpt <= 0) {
 110 #ifdef USE_LOCALE
 111                 while((*b = *decimalpoint++))
 112                         ++b;
 113 #else
 114                 *b++ = '.';
 115 #endif
 116                 if (be < b - decpt + (se - s))
 117                         goto ret0;
 118                 for(; decpt < 0; decpt++)
 119                         *b++ = '0';
 120                 while((*b = *s++) != 0)
 121                         b++;
 122                 }
 123         else {
 124                 while((*b = *s++) != 0) {
 125                         b++;
 126                         if (--decpt == 0 && *s) {
 127 #ifdef USE_LOCALE
 128                                 while(*b = *decimalpoint++)
 129                                         ++b;
 130 #else
 131                                 *b++ = '.';
 132 #endif
 133                                 }
 134                         }
 135                 if (b + decpt > be) {
 136  ret0:
 137                         b = 0;
 138                         goto ret;
 139                         }
 140                 for(; decpt > 0; decpt--)
 141                         *b++ = '0';
 142                 *b = 0;
 143                 }
 144  ret:
 145         freedtoa(s0);
 146         return b;
 147         }