proj/src/rtodms.c

   1 /* Convert radian argument to DMS ascii format */
   2 #include <projects.h>
   3 #include <stdio.h>
   4 #include <string.h>
   5 /*
   6 ** RES is fractional second figures
   7 ** RES60 = 60 * RES
   8 ** CONV = 180 * 3600 * RES / PI (radians to RES seconds)
   9 */
  10         static double
  11 RES = 1000.,
  12 RES60 = 60000.,
  13 CONV = 206264806.24709635515796003417;
  14         static char
  15 format[50] = "%dd%d'%.3f\"%c";
  16         static int
  17 dolong = 0;
  18         void
  19 set_rtodms(int fract, int con_w) {
  20         int i;
  21
  22         if (fract >= 0 && fract < 9 ) {
  23                 RES = 1.;
  24                 /* following not very elegant, but used infrequently */
  25                 for (i = 0; i < fract; ++i)
  26                         RES *= 10.;
  27                 RES60 = RES * 60.;
  28                 CONV = 180. * 3600. * RES / PI;
  29                 if (! con_w)
  30                         (void)sprintf(format,"%%dd%%d'%%.%df\"%%c", fract);
  31                 else
  32                         (void)sprintf(format,"%%dd%%02d'%%0%d.%df\"%%c",
  33                                 fract+2+(fract?1:0), fract);
  34                 dolong = con_w;
  35         }
  36 }
  37         char *
  38 rtodms(char *s, double r, int pos, int neg) {
  39         int deg, min, sign;
  40         char *ss = s;
  41         double sec;
  42
  43         if (r < 0) {
  44                 r = -r;
  45                 if  (!pos) { *ss++ = '-'; sign = 0; }
  46                 else sign = neg;
  47         } else
  48                 sign = pos;
  49         r = floor(r * CONV + .5);
  50         sec = fmod(r / RES, 60.);
  51         r = floor(r / RES60);
  52         min = fmod(r, 60.);
  53         r = floor(r / 60.);
  54         deg = r;
  55
  56         if (dolong)
  57                 (void)sprintf(ss,format,deg,min,sec,sign);
  58         else if (sec) {
  59                 char *p, *q;
  60
  61                 (void)sprintf(ss,format,deg,min,sec,sign);
  62                 for (q = p = ss + strlen(ss) - (sign ? 3 : 2); *p == '0'; --p) ;
  63                 if (*p != '.')
  64                         ++p;
  65                 if (++q != p)
  66                         (void)strcpy(p, q);
  67         } else if (min)
  68                 (void)sprintf(ss,"%dd%d'%c",deg,min,sign);
  69         else
  70                 (void)sprintf(ss,"%dd%c",deg, sign);
  71         return s;
  72 }