Source:NetHack 3.6.0/src/track.c

Below is the full text to track.c from the source code of NetHack 3.6.0. To link to a particular line, write [[Source:NetHack 3.6.0/src/track.c#line123]], for example.

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/* NetHack 3.6	track.c	$NHDT-Date: 1432512769 2015/05/25 00:12:49 $  $NHDT-Branch: master $:$NHDT-Revision: 1.9 $ */
/* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
/* NetHack may be freely redistributed.  See license for details. */
/* track.c - version 1.0.2 */

#include "hack.h"

#define UTSZ 50

STATIC_VAR NEARDATA int utcnt, utpnt;
STATIC_VAR NEARDATA coord utrack[UTSZ];

void
initrack()
{
utcnt = utpnt = 0;
}

/* add to track */
void
settrack()
{
if (utcnt < UTSZ)
utcnt++;
if (utpnt == UTSZ)
utpnt = 0;
utrack[utpnt].x = u.ux;
utrack[utpnt].y = u.uy;
utpnt++;
}

coord *
gettrack(x, y)
register int x, y;
{
register int cnt, ndist;
register coord *tc;
cnt = utcnt;
for (tc = &utrack[utpnt]; cnt--;) {
if (tc == utrack)
tc = &utrack[UTSZ - 1];
else
tc--;
ndist = distmin(x, y, tc->x, tc->y);

/* if far away, skip track entries til we're closer */
if (ndist > 2) {
ndist -= 2; /* be careful due to extra decrement at top of loop */
cnt -= ndist;
if (cnt <= 0)
return (coord *) 0; /* too far away, no matches possible */
if (tc < &utrack[ndist])
tc += (UTSZ - ndist);
else
tc -= ndist;
} else if (ndist <= 1)
return (ndist ? tc : 0);
}
return (coord *) 0;
}

/*track.c*/