Function worm_move

src/worm.c:195–278

* worm_move() * * Check for mon->wormno before calling this function! * * Move the worm. Maybe grow. */

 *  Move the worm.  Maybe grow.
 */
void
worm_move(struct monst *worm)
{
    struct wseg *seg, *new_seg; /* new segment */
    int wnum = worm->wormno;    /* worm number */

    /*
     *  Place a segment at the old worm head.  The head has already moved.
     */
    seg = wheads[wnum];
    place_worm_seg(worm, seg->wx, seg->wy);
    newsym(seg->wx, seg->wy); /* display the new segment */

    /*
     *  Create a new dummy segment head and place it at the end of the list.
     */
    new_seg = newseg();
    new_seg->wx = worm->mx;
    new_seg->wy = worm->my;
    new_seg->nseg = (struct wseg *) 0;
    seg->nseg = new_seg;    /* attach it to the end of the list */
    wheads[wnum] = new_seg; /* move the end pointer */

    if (wgrowtime[wnum] <= svm.moves) {
        int whplimit, whpcap, prev_mhp, wsegs = count_wsegs(worm);

        /* first set up for the next time to grow */
        if (!wgrowtime[wnum]) {
            /* new worm; usually grow a tail segment on its next turn */
            wgrowtime[wnum] = svm.moves + rnd(5);
        } else {
            int mmove = mcalcmove(worm, FALSE),
                /* prior to 5.0.0,, next-grow increment was 3..17 but since
                   it got checked every 4th turn when the speed 3 worm got
                   to move, it was effectively 0..5; also, its usage was
                   'wgrowtime += incr', so often 'wgrowtime' would be
                   exceeded by 'moves' on consecutive turns for the worm,
                   resulting in an excessively rapid growth cycle */
                incr = rn1(10, 2); /* 2..12; after adjusting for long worn
                                    * speed of 3, effective value is 8..48 */

            incr = (incr * NORMAL_SPEED) / max(mmove, 1);
            wgrowtime[wnum] = svm.moves + incr;
        }

        /* increase HP based on number of segments; if it has shrunk, it
           won't gain new HP until regaining previous peak segment count;
           when wounded (whether from damage or from shrinking), the HP
           which might have been 'new' will heal */
        whplimit = !worm->m_lev ? 4 : (8 * (int) worm->m_lev);
        /* note: wsegs includes the hidden segment co-located with the head */
        if (wsegs > 33)
            whplimit += 2 * (wsegs - 33), wsegs = 33;
        if (wsegs > 22)
            whplimit += 4 * (wsegs - 22), wsegs = 22;
        if (wsegs > 11)
            whplimit += 6 * (wsegs - 11), wsegs = 11;
        whplimit += 8 * wsegs;