reactos/lib/sdk/crt/misc/i10output.c

   1 #include <precomp.h>
   2
   3 #define I10_OUTPUT_MAX_PREC 21
   4 /* Internal structure used by $I10_OUTPUT */
   5 struct _I10_OUTPUT_DATA {
   6     short pos;
   7     char sign;
   8     BYTE len;
   9     char str[I10_OUTPUT_MAX_PREC+1]; /* add space for '\0' */
  10 };
  11
  12 /*********************************************************************
  13  *              $I10_OUTPUT (MSVCRT.@)
  14  * ld - long double to be printed to data
  15  * prec - precision of part, we're interested in
  16  * flag - 0 for first prec digits, 1 for fractional part
  17  * data - data to be populated
  18  *
  19  * return value
  20  *      0 if given double is NaN or INF
  21  *      1 otherwise
  22  *
  23  * FIXME
  24  *      Native sets last byte of data->str to '0' or '9', I don't know what
  25  *      it means. Current implementation sets it always to '0'.
  26  */
  27 int CDECL MSVCRT_I10_OUTPUT(long double ld, int prec, int flag, struct _I10_OUTPUT_DATA *data)
  28 {
  29     static const char inf_str[] = "1#INF";
  30     static const char nan_str[] = "1#QNAN";
  31
  32     double d = ld;
  33     char format[8];
  34     char buf[I10_OUTPUT_MAX_PREC+9]; /* 9 = strlen("0.e+0000") + '\0' */
  35     char *p;
  36
  37     TRACE("(%lf %d %x %p)\n", d, prec, flag, data);
  38
  39     if(d<0) {
  40         data->sign = '-';
  41         d = -d;
  42     } else
  43         data->sign = ' ';
  44
  45     if(!_finite(d)) {
  46         data->pos = 1;
  47         data->len = 5;
  48         memcpy(data->str, inf_str, sizeof(inf_str));
  49
  50         return 0;
  51     }
  52
  53     if(_isnan(d)) {
  54         data->pos = 1;
  55         data->len = 6;
  56         memcpy(data->str, nan_str, sizeof(nan_str));
  57
  58         return 0;
  59     }
  60
  61     if(flag&1) {
  62         int exp = (int)(1+floor(log10(d)));
  63
  64         prec += exp;
  65         if(exp < 0)
  66             prec--;
  67     }
  68     prec--;
  69
  70     if(prec+1 > I10_OUTPUT_MAX_PREC)
  71         prec = I10_OUTPUT_MAX_PREC-1;
  72     else if(prec < 0) {
  73         d = 0.0;
  74         prec = 0;
  75     }
  76
  77     sprintf(format, "%%.%dle", prec);
  78     sprintf(buf, format, d);
  79
  80     buf[1] = buf[0];
  81     data->pos = atoi(buf+prec+3);
  82     if(buf[1] != '0')
  83         data->pos++;
  84
  85     for(p = buf+prec+1; p>buf+1 && *p=='0'; p--);
  86     data->len = (BYTE)(p - buf);
  87
  88     memcpy(data->str, buf+1, data->len);
  89     data->str[data->len] = '\0';
  90
  91     if(buf[1]!='0' && prec-data->len+1>0)
  92         memcpy(data->str+data->len+1, buf+data->len+1, prec-data->len+1);
  93
  94     return 1;
  95 }
  96 #undef I10_OUTPUT_MAX_PREC
  97
  98
  99