On Tuesday, June 4, 2002, at 01:22 am, Andy Ross wrote:
>
> Heh, that actually sounded kinda fun, so I tried it. Here's the
> smallest parser for your syntax that I could come up with, in good old
> obfuscatorial C style. It sits pleasingly close to the line between
> elegance and perversity.
Thanks very much, some comment below...
>
> 37�54.204' N
How do you generate a degree symbol under Linux? I was trying to and
failed miserably ...
> #include <stdio.h>
> #include <stdlib.h>
> #include <string.h>
>
> double parseLatLon(char* s)
> {
> char buf[64];
> int i, len, top=0;
> double stk[32], sign=1;
32 seems a trifle excessive, I might go with 4 ... not a big deal though.
> strncpy(buf, s, 64);
> len = strlen(buf);
>
> for(i=0; i<len; i++) {
> char c = buf[i];
> if((c>='0' && c<='9') || c=='-' || c=='.' || c=='+')
> continue; /* Digit characters are cool as is */
> if((c|32) == 'w' || (c|32) == 's')
> sign = -1; /* These mean "negate" (note case
> insensitivity) */
> buf[i] = 0; /* Replace everything else with nuls */
> }
>
> /* Build a stack of doubles */
> stk[0] = stk[1] = stk[2] = 0;
> for(i=0; i<len; i++) {
> while(i<len && buf[i] == 0) i++;
> if(i != len) {
> stk[top++] = atof(buf+i);
Would prefer to use strtod here, atof is deprecated. not sure about
platform compatibility though.
> i += strlen(buf+i);
> }
> }
>
> return sign * (stk[0] + (stk[1] + stk[2] / 60) / 60);
> }
>
> int main(int argc, char** argv)
> {
> printf("%f\n", parseLatLon(argv[1]));
> return 1;
> }
>
Other than this, it looks great, I'll add it to my code (currently
piling up in src/Navaids). If people decide it it's general enough to
move to SimGear in the future, all the better.
BTW, the route stuff is coming along nicely, working on the XML / input
side. I am currently coding up support for flight-plans / routes with
navaids, fixes and 'direct' positions (hence the need for the above
code). Each point can have altitude and/or speed restrictions. In
addition to the basic types, flight plans can contain airway and
procedure segments. The flight plan will automatically pick transitions
on the airways / SIDs / STARs / APs based on the next / preceding points
on the flight plan.
Once this is all coded up and tested (by next weekend, I hope), I need
to start wiring it up to the current auto-pilot logic, and then I might
actually be able to fly a plan, which would be pretty cool.
H&H
James
--
What I like about deadlines is the lovely whooshing sound they make as
they rush past. -- Douglas Adams
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